|Auburn University Digital Library|
|Managing Tropical Animal Resources - Crocodiles as a Resource for the Tropics|
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Experiences with crocodile farming in Papua New Guinea, the main subject of this report, are described in chapter 2. Here we summarize the status of similar efforts in other countries.
Four crocodile farms have been established in Australia, one in the Northern Territory and three in Queensland. To date, only the Edward River farm, operated by the government as an aboriginal development project, has developed a successful breeding program. There, seven-yearold saltwater crocodiles (Crocodylus porosus) hatched on the farm from wild eggs are now breeding and laying fertile eggs.
People's Republic of China
A farm for Chinese alligators (Alligator sinensis) has been established at Xuancheng, Anhui Province. Its purpose is to breed alligators for conservation, although the hide of this species is not in great demand because it has many osteoderms in the belly scales. Recently the government has expressed interest in establishing a farm for saltwater crocodiles in southern China.
Taiwan has one crocodile farm or rearing station, but it is too far north to breed its own stock, except in heated indoor enclosures.
There are several buyers in the Philippines who maintain pens of crocodiles for short periods. None of these is a farm. A new experimental farm for the Philippine freshwater crocodile (Crocodylus novaeguineae mindorensis) was established by Silliman University in an attempt to preserve that endangered species and to promote an economic interest in crocodile conservation.
A farm for saltwater crocodiles has been established on Palau, where a small population of these crocodiles occurs in a brackish interior swamp. In the past, the government hired a hunter to reduce the population whenever the local people felt it had become sufficiently large to present a danger, about once a decade. Presumably the nuisance crocodiles will now end up in the farm. The farm, which has been in existence only for a year or two, earns money from tourist admissions as well as hide production.
A few crocodile-rearing stations have operated for several decades in Java, Sumatra, and Kalimantan. These have been stocked with eggs and young animals collected from the wild in Sumatra and Kalimantan. In the early 1970s, three such operations in Samarinda, East Kalimantan, closed down for lack of wild stock. At least one operation in Jakarta, Java, continues to survive, but with virtually no output of stock.
A survey of Irian Jaya (Indonesian New Guinea) in 1980 indicated a number of ranches in that region as well, but revealed that some were having difficulty obtaining stock because of overharvest.
Singapore has a famous crocodile farm that figures prominently in tourism. It breeds some of its stock, but also obtains wild stock from all over Southeast Asia. Singapore has a thriving crocodile hide trade. Many buyers and several tanneries are located there.
Singapore is not a member of CITES and openly trades in any and all species of crocodilians.
There are several crocodile farms in West Malaysia (at Penang, for example) and at least one in East Malaysia (near Sandakan, Sabah). These started out as rearing stations relying on wild young, but have moved slowly toward breeding their own stock. The Penang farm depends on tourism to pay many of its expenses. The Sandakan farm is operated in conjunction with a duck and pig farm that supplies it with offal. Its stock consists of saltwater crocodiles. Until at least 1980, it had very little production from captive animals, but the owner is hoping to broaden his stock from them.
Sarawak (East Malaysia) also used to have several rearing farms. The present status of these operations is unknown.
The Samutprakan Crocodile Farm was started in 1950 with 20 wild crocodiles and an investment of US$500. Today it is reported to be the world's largest crocodile farm, with about 30,000 individuals. About 3,700 of these animals, placed in eight separate breeding ponds, are used for breeding stock, and there are plans for a population of 100,000 by 1987. The Samutprakan farm opened to the public 12 years ago and now receives about one million visitors annually.
Most of the farm's crocodiles are from the two species native to Thailand, the saltwater crocodile and the Siamese freshwater crocodile (Crocodylus siamensis). It also has hybrids of the two, as well as the indigenous false gavial (Tomistoma schlegelii) and five exotic species: South American caiman (Caiman crocodilus), New Guinea freshwater crocodile (Crocodylus novaeguineae), Chinese alligator (Alligator sinensis), broad-spouted caiman (Caiman latirostris), and dwarf caiman (Paleosuchus palpebrosus). The farm has succeeded in breeding South American caiman (Caiman crocodilus); the other species are approaching maturity and it is hoped they will breed in the near future.
The farm sells crocodile meat locally, mostly to restaurants as a delicacy (for US$5 per kg).
The commercial and biological success of the farm is largely due to favorable conditions at Samutprakan. The temperature and humidity are high year-round, and low costs of labor and building materials permit the physical plant to be profitably established and maintained. The main cost is for food; approximately 4,000-5,000 kg of by-catch fish are needed daily at a cost of US 20 cents per kg. If the supply of fish is inadequate, the diet is supplemented with chicken wings, legs, and necks from a slaughterhouse.
In Rangoon there are some crocodile-holding pens operated by hide buyers. It is not clear whether breeding or farming of crocodiles occurs in them or whether the operation simply acts as a clearing center for wild hides. The government has expressed interest in establishing farms in the mangrove areas near the mouth of the Irrawaddy River.
In 1974 an FAO report on India's crocodiles noted that the Indian gavial (Gavialis gangeticus) was on the verge of extinction, the saltwater crocodile was extremely rare, and the Indian mugger (Crocodylus palustris was a depleted, although not threatened, species).
The government, with United Nations assistance, then initiated a project for the conservation and management of all three species. This program aimed to protect and restock habitats. Animals for restocking were obtained by collecting eggs laid in the wild, incubating them under controlled conditions, raising the resulting hatchlings, and returning juveniles to specially selected sanctuaries when they reached about 1.2 m in length,at which time they are free from predation other than by man.
The project has resulted in the comeback of the gavial. By March 1979, 200 gavials had been restored to the wild. The wild population now exceeds 1,000 animals of more than 2 m length, and the number is expected to increase rapidly through natural reproduction.
The project has also carried out extensive research on crocodiles, and since its founding in 1978 the Central Crocodile Breeding and Management Training Institute, located in Hyderabad, has trained many wildlife officers in crocodile protection. Crocodile-rearing facilities are also located near Madras, Lucknow, and Cuttack. All have had success in raising the animals and restocking their habitats.
The Indian crocodile project has been a notable success and it coincided with (and perhaps helped create) a wave of local interest in India's wildlife and its conservation.
A farm stocked with American alligators (Alligator mississippiensis) was established at a popular hotwater spring resort area, using animals supplied by a Florida farm. The Israeli program will earn money from tourist admissions and from future production of hides. The first successful hatching of captive-bred alligators was reported in 1982.
Near Mombasa a farm for the Nile crocodile (Crocodylus niloticus) has been set up to produce hides from captive-bred stock. The farm is a demonstration project of a large cement factory that is attempting to return its limestone-mined areas to productive agriculture. Some sophisticated experiments are under way on crocodile nutrition, with food for the animals produced in an intensive aquaculture project using tilapia.
Zambia is planning a series of farms patterned after those in Zimbabwe (described below).
Zimbabwe has made great strides in captive breeding. In 1979, 87 captive females at two farms produced 1,906 eggs, and a third farm has set aside 30 captive females for breeding.
Four of the country's five crocodile farms are on the shores of Lake Kariba and the other is at Victoria Falls. The government allows each farm an annual allotment of wild eggs (averaging 2,000 to 2,500 eggs) for stocking its rearing programs. Each farm is also striving to become self sufficient in egg production by developing successful breeding programs. The government is considering reducing each farm's allotment by the number of eggs produced annually in the farm so that each will eventually become independent of the wild populations.
Zimbabwe farmers operate on a system that obliges them to return a small percentage of live animals to the wild if the government requires it. At present, this requirement is being waived because the wild population is increasing on its own.
Zimbabwe has built its crocodile conservation program on a broad base. Crocodiles are protected throughout the country, as game animals in the country at large and as totally protected species in parks and sanctuaries. Populations have increased dramatically, from endangered status in the l950s to over 50,000 individuals today. In the 1950s a survey of the Zambesi River and Lake Kariba revealed no crocodiles; today thousands are seen.
Zimbabwe's Department of National Parks and Wildlife is striving to ensure that its legitimate international trade in farm-raised hides does not provide illegal operators in other countries with the opportunity to sell poached hides (for example, forging papers that claim their hides originated on legitimate Zimbabwe farms). To make poaching difficult, Zimbabwe, taking a clue from the state of Louisiana, plans to use serially numbered nonremovable plastic tags to mark legitimate hides. Numbers of the tags will be noted on export permits. In addition, every export permit will be validated by the government with an engraved security stamp that is difficult to forge and that shows ink damage if any erasures or modifications are attempted. The use of such stamps is recommended by CITES, and Zimbabwe is the first nation to put them into use.
South Africa has four crocodile farms, and another five are planned or under construction. Apart from the Natal Parks Board Crocodile Research Station at St. Lucia Estuary, which breeds Nile crocodiles for restocking and conservation purposes, all farms are for tourism and hide production. So far only one farm, outside Pretoria, is reported to produce many offspring. Only the provinces of Transvaal and Natal have wild crocodiles, and neither allows eggs, young, or adults to be collected for stocking farms. Both provinces, however, permit the killing of nuisance crocodiles on private land. Transvaal will allow one or two nuisance crocodiles to be taken captive by farmers, but it refuses permission for removing larger numbers of nuisance animals,presumably for fear that this would generate a flood of spurious nuisance complaints. Natal will not permit the removal of any wild crocodiles to farms, nor will it supply offspring from the St. Lucia station to farmers. This makes the Pretoria farm the only source of crocodiles in South Africa.
Following the example of Zimbabwe, the South African farmers (present and potential) formed a crocodile farming association in 1982.
Several farms patterned after those in Zimbabwe are planned for the Okavango area. Petitions for approval are currently before the Botswana government.
In the late 1960s French businessmen established a farm for Nile crocodiles near Lake Chad. It collapsed after only a few years.
The government of Ivory Coast has obtained assistance from Zimbabwe to establish a conservation program for its three native crocodiles: the Nile crocodile, African slender-spouted crocodile (Crocodylus cataphractus), and Congo dwarf crocodile (Osteolaemus tetraspis). Recommendations were made for conserving the wild populations as well as for establishing farms. Field studies are under way.
A commercial farm for the South American caiman (Caiman crocodilus) was established in southern Italy in the late 1970s. Stock was obtained from Colombia. The animals, numbering in the thousands, arrived in Rome in winter and were transported south to the farm in an open truck. Most died from cold. Later shipments fared no better, and the few animals that survived died from poor husbandry.
There are between 15 and 20 successful alligator farms in the United States. Most are located in Florida and Louisiana, and there is at least one in California. All earn a portion of their money from tourist admissions.
In the 1960s the Cuban government established at least two farms for crocodiles. One is located in the Zapata Peninsula National Park; the other is near Cienfuegos. The purpose of these farms is to breed crocodiles whose wetland habitat has been converted to sugar cane fields. Eventually, the farms will also produce a cash crop of hides.
Unfortunately, what started out as an admirable effort created several conservation problems because the farm managers did not realize there were two crocodiles in Cuba ,the American crocodile (Crocodylus acutus) in brackish waters, and the Cuban crocodile (Crocodylus rhombifer) in freshwater areas. The two were mixed in the farms and hybridization resulted.
The Mexican government has established several farms for Morelet's crocodile (Crocodylus moreletii) in Chiapas and Veracruz. The purpose is to breed the species in captivity to relieve hunting pressure on the wild population and prevent its extinction. Original funding was provided by the World Wildlife Fund. At least one of these farms still exists. Breeding has been achieved, but there have been problems of survival in hatchlings. The cause of the deaths has not been discovered.
In recent years several businessmen in Mexico have expressed interest in starting one or more crocodile farms, but none has yet materialized.
In the late 1960s, the Louisiana Game and Fisheries Commission supplied specimens of the American alligator to a cattle rancher in El Salvador for the purpose of establishing an experimental farm.
Louisiana was interested in studying growth rates of American alligators in a tropical nation where the animals did not have to undergo winter hibernation. The husbandry on the farm followed methods worked out in Louisiana. The animals grew fast and presumably have started breeding.
A captive breeding program for the Orinoco crocodile (Crocodylus intermedius) was established in Venezuela in the late 1970s on the ranch of Tomas Blohm. The operation is not commercial; its purpose is to prevent extinction of the species. The offspring may be used for restocking wild habitats in the future.
Under Venezuelan law there can be no commercial export of any crocodilians. In addition, the Orinoco crocodile and the various caimans are protected. However, the reptiles are everywhere killed as vermin.
Peru has proposed harvesting certain wild populations of caimans (Caiman crocodilus) to supply animals to a ranching operation.
The government of Brazil is interested in establishing farms for several species of caiman, including the yacare (Caiman crocodilusyacare).
Other Latin American Nations
During the past two years, other Central and South American nations that have indicated their intention to set up farms for crocodiles or caimans are Bolivia, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Nicaragua, Panama, Paraguay, Suriname, and Uruguay.
This appendix is adapted from a paper by A. Pooley that detailed the lessons learned from farming crocodiles to restock depleted habitats in Natal, South Africa. The information is presented here not as a blueprint for setting up a farm, but to show prospective farmers some of the points that they must first consider before attempting to rear crocodiles.
Reliable supplies of good water and suitable food are the most important considerations for establishment of a crocodile farm; the area selected must have both. Village farms also need to be close enough to wild crocodile populations for the animals to be obtained easily. Larger farms can be located farther from the source.
For small farms, a natural supply of food should also be readily available in the wild. Areas that have a fishing industry are ideal locations. For large farms, sites near slaughterhouses or fish-processing facilities are ideal.
Other considerations also include the volume of water available throughout the year, the distance over which water must be piped to the ponds, and pumping costs. The quality of the water should be established, with samples tested for salinity and acidity and, where the supply comes from mineral springs, analyzed for harmful chemicals. Chlorinated water must be tested regularly to ensure that the chlorine content is not too high, and the nature of any factory effluents present should be determined. It is important to establish whether fish, frogs, crabs, mollusks, or aquatic insects survive in the water intended for use.
Bacterial analysis is advisable where the water is drawn from a river that drains an area densely populated by humans and livestock. If the water is found to be contaminated, the stagnant pond rearing pen system should not be used, particularly when Salmonella spp. are present in high concentrations.
A filter system has advantages if water is pumped straight from a river carrying a heavy silt load. Apart from enabling farmers to see the animals in the pools, filtered water makes the pools and pipes easier to clean. Filtration can be achieved by drawing water from a deep pit close to the river so that the water collected seeps through sand or mud.
A reservoir or a series of supply tanks is useful as an additional method of filtering water. In the event that pumping equipment fails, such a reserve supply may prove vital to the health and survival of the crocodiles.
The ponds should receive as much sun as possible, particularly during the winter months. A series of winter air temperature recordings would be useful in choosing the site of rearing pens, since valley temperatures are often several degrees lower than the temperatures some 50 to 100 m uphill. Preference should be given to the warmer locations, taking into account the direction of local winds and heavy rains.
Soil types are the next consideration. If soils are sandy and porous, earth ponds are impractical and a concrete lining is required to retain water.
Drainage of the ponds must be carefully considered. Drainage is far easier if the ponds are built on a slight rise. Water from the ponds must not be allowed to stagnate nearby; the drainage system must be efficient. It is recommended that pens be spaced at least 8 m apart and that their drainpipes lead underground at least 10 m before emptying.
Pens with rounded corners are the most successful. Crocodiles frequently choose to lie together in a pile. Square corners allow them to pile up against the angle, smothering those on the bottom and sometimes allowing animals to climb over the fence. With rounded corners, the pile cannot grow very high before the crocodiles slide sideways and the heap collapses.
Experiments in South Africa indicate that natural pools containing rooted vegetation are less prone to become sources of disease than are concrete pools. The surface of the concrete seems to become impregnated with liquid and debris from food and to become a breeding ground for bacteria. For hatchlings and very small juvenile crocodiles, concrete has an added disadvantage; its rough surface can abrade the belly skin when the animals slide in and out of the water, which can foster infection. In 5 or 10 years, even smooth concrete will erode sufficiently to become a problem.
Researchers elsewhere, however, report better results with concrete lined ponds, which they find easier to clean. Concrete pools are useful for summer because they can be scrubbed clean and because the volume of water used is small. Normally they need only be emptied, cleaned, and refilled every third day, and there is no wastage through seepage.
The pools are best built as channels. This provides more bank for basking and enables the pools to accommodate more crocodiles. Because the larger males become belligerent only when they can see each other, floating logs, patches of grass, or channel corners are visual barriers that reduce interactions. The channel system also gives more water edge, and this appears to satisfy the territorial instinct.
Crocodiles are famous for basking in the sun, but they die surprisingly easily of heat prostration. At least one-third of the land area of a farm pen should be shaded with vegetation. The amount of space around each pool is calculated to allow ample basking room for each animal, and an area of shade must likewise be provided.
On land, crocodiles often seek contact with each other (thigmotaxis) and frequently lie piled on top of each other, but this should be a matter of choice rather than of overcrowding. There should be few enough animals in the enclosure to allow every crocodile to get out of the water if it chooses.
Ideally, only half the available number of pools should be occupied at a time, so that they can be used in rotation. In this system, the animals can be moved to fresh pools every two months (or as necessary), leaving the "used" pools to be drained and dried out to bake in the sun. After two months, the pools will then be clean and ready for use again.
An important requirement is that the pools be at least 60 cm in depth; otherwise, the water becomes too hot in summer. The pool floor should be sloped towards the drain outlet to facilitate cleaning and flushing away uneaten food. Also, the outlet pipe should be 10 cm in diameter, with a stopcock outside the enclosure, so that the pool can be cleaned and emptied efficiently. It is essential to place a screen in the drainpipe to prevent small crocodiles from escaping or being sucked out of the pool during cleaning. After some time, stagnant ponds may become difficult to clean because of the heavy growth of algae on their sides. Hard-bristle scrubbing brushes are needed to dislodge this growth. Small amounts of copper sulfate in the water will help control algae if used regularly.
The entire pond and surrounding apron must be smoothly plastered to facilitate cleaning. It helps to have a water source close to each pool from which a hose pipe can be led to pressure spray and clean the pool and its apron.
An important part of the design is a partly submerged, gently sloping ledge, some 45 cm in width, around the perimeter of the pool. This provides a shallow resting zone for the crocodiles and gives them easy access to the water. The crocodiles rest there when feeding, and the ledge prevents them from scraping their bellies and damaging their claws when they enter or leave the pool.
For small crocodiles it is advisable to roof over the entire pen with wire netting or cries-crossed strands of wire. This protects against predators. Further, young crocodiles can climb vertical wire netting with ease and will escape unless the enclosure is either roofed or has side walls that slope inwards. A skirting board (planking, sheet iron, tin, or plastic sheeting) placed against the wire netting can also prevent this. If wire netting is used for the sides of the pens it should have mesh no larger than 1 cm so that hatchlings will not injure themselves by trying to climb through. While these pools are being cleaned, care must be exercised to prevent crocodiles from falling into the empty pool.
Water can be passed continuously through the pools. The advantage of this is that during hot summer weather, when crocodiles are feeding at their maximum rate, small uneaten food particles, feces, and urine are carried away. Constant dilution of the pond's water also ensures a low bacteria level. However, the pool must be drained and scrubbed clean at least weekly.
Earthen pools are easy and cheap to build and are a "natural" habitat where vegetation can be planted and small live fish introduced; insects, frogs, and other creatures attracted to the dams will be an important addition to the diet and health of the crocodiles. Earthen pools are ideal in climates where low winter temperatures are likely to cause respiratory illness in the young animals. During cold weather the crocodiles burrow into the mudbanks and survive nights of heavy frost.
Because of the animal's burrowing capabilities, it is important to provide a strip of land 4 m wide between the pool's edge and the boundary fence. Otherwise, crocodiles may tunnel beyond the fence line. Fences must be buried at least 1 m deep to intercept the burrows and to prevent predators from burrowing in. Burrowing, however, can be hazardous, because the burrows can collapse and suffocate the animals.
In areas where the soil is porous or sandy, the floor of an earth dam can be sealed with concrete or plastic irrigation sheets. A layer of earth can be used to conceal this artificial floor. The disadvantages of earth pools are that, because of seepage, they require more water than concrete ones and that they require more maintenance because they cannot be efficiently cleaned. Even if the pools are provided with constantly circulating water, they eventually become fouled, particularly during hot weather.
Removing crocodiles from an earth pond can prove difficult, since most will take refuge in their burrows.
Crocodiles are located at night, usually from a boat, by shining a light along the edges of rivers and lagoons. Because of a reflective tapetum, the eyes of crocodiles glow reddish or orange and are visible for a hundred meters or more. If the population has not become exposed to hunting and become wary of people, the animals will not submerge when the light strikes them. Dazzled by the beam, they tolerate a stealthy approach, and small animals can simply be grabbed by hand or scooped up in a net. They can then be transported in sacks to the rearing pens. Larger animals may be noosed or baited into cylindrical screen traps at places they frequent along the water's edge.
Managing a Crocodile Farm
It is a problem to sort the young crocodiles. From one clutch of eggs, some individuals will be aggressive and others may be shy or extremely timid; growth may vary from rapid to very slow, with a few individuals classed as runts.
Larger animals can be so dominant that smaller individuals will not even attempt to feed. If sorting is not done, the smaller, less-aggressive individuals do not get a fair share of the food; they grow slowly and get bitten and harassed by the larger animals. At feeding time, some will flee to the opposite side of the pen and stop feeding altogether. Keeping the young animals sorted into classes of the same size avoids many of these problems.
Nutrition and Feeding
Despite the crocodilian's reputation as a man-eater, small wild crocodiles live mainly on invertebrates and larger ones live mainly on fish. Papua New Guinea's farmers feed a varied diet of locally caught fish, crab, shrimp, frogs, snails, grasshoppers, beetles, and slaughterhouse waste. Whole animals minced up should be used, if necessary, because crocodiles require a diet of bone, intestine, scales, and other tissues to provide calcium and minerals. Bones in chopped fish must be minced thoroughly for hatchlings or very young crocodiles, or they should be fed very small fish supplemented by tadpoles or insects. One village in Papua New Guinea has shown remarkable success in rearing hatchlings on a diet of chopped fish and live freshwater shrimp.
Fish is an excellent food for the bulk feeding of a large captive population. Whole fish chopped into pieces, including the livers and hearts, forms a balanced diet that may be supplemented by meat, if available, to make up bulk. Small whole fish are particularly suitable; the crocodiles derive calcium from the bones and scales, plus roughage to facilitate digestion, while the flesh, liver, and heart are rich in nutrients and protein The main difficulty usually lies in harvesting enough fish to meet the crocodiles' demands.
Any method of supplementing the diet with live creatures is recommended. For instance, a light can be left burning in each pen about 15 cm above the water for attracting insects. Various types of insect traps may also be used.
Crocodiles also can be fed on a variety of wastes such as offal or noncommercial fish. Ideally, a large-scale farm should be located near a poultry slaughterhouse. (Cattle offal is also satisfactory, but it is not nutritionally adequate as a sole ration for crocodiles.) Even crocodile offal itself can be fed back to crocodiles. However, the use of offal will necessitate dietary supplements to assure sufficient phosphorus and calcium. These minerals are generally provided by feeding bones to the crocodiles.
Crocodiles usually consume their food in the water, but they can also be fed on land. They will eat daily, but are able to remain active for weeks without food. If they are fed in the water of a farm pen, the water will become polluted unless there is considerable flow to carry away the debris. In extreme cases, the pools become septic. To ensure the health of the growing animals, constantly flowing water is far superior to standing water. (The Samutprakan Crocodile Farm in Thailand feeds some of its animals in water, but the small feeding pools are separate from the large regular breeding pools and at a lower level to prevent their overflowing into the breeding pools.)
It is important to feed pieces of food small enough to be swallowed without difficulty. Large fish should be cut into elongated rather than square pieces, since the bones can cause damage during swallowing. Similarly, whole live fish should not be so large that the dorsal fin may cause damage to the reptile's throat and gullet.
It is important to know the amount of food that each group of animals will consume at each meal. By feeding at the same time each day, it is easy to calculate how much is required. Moreover, the crocodiles become accustomed to a routine and the food is consumed while it is still fresh. In the hot summer months the animals will devour a full meal every 24 hours, but the feeding rate slackens with the onset of colder weather. It is then wise to start reducing frequency and quantities until food is required only every second or third day, depending on the climate. Generally, young crocodiles will refuse food when the air or water temperature falls below 60°F (15.6°C). Even in midsummer sudden cold spells may occur; at such times, it is usually futile to feed the animals or try to coax them to eat until the weather warms up again.
During hot weather conditions it is preferable to feed late in the afternoon or evenings, mainly to avoid placing the food on a hot cement surface. The food should be spread out around the edge of the pool under the shaded area so that the animals do not have to climb over one another to reach it.
In cemented pens the area where the food is laid out should be cleaned and scrubbed two hours after feeding time and any uneaten food removed from the water with a hand net. In earthen pools, the food should be placed at a different spot along the bank at each feeding. A useful aid to hygiene is keeping a few predacious fish, such as barbel (Clarias spp.), in each pool to clean up scraps of uneaten food.
Twenty-five crocodiles are considered the maximum manageable number per unit; staying within this limit reduces competition for food, bullying and fighting, and the number of injuries. A low stocking rate also results in a more even average growth rate. Most important is the fact that the overall health of the crocodiles is better than in a more crowded pen; disease problems are fewer and the symptoms easier to detect in a small group. If the units are spaced 8 m apart, there is also less danger of infectious disease spreading to other pens. The cleaning of pens is facilitated, and the disturbance caused by capturing crocodiles to be moved to other units is minimized. Housing 500 crocodiles in groups of 25 will require 20 separate pens, and an additional two pens should be provided to allow for intensive care of sick, injured, and weaker animals.
During the first year, when animals are graded frequently, they will often be moved from one pen to another. Recording the number of animals housed in each pen will make it possible to keep track of numbers and movements.
Reproduction is impossible when crocodiles are kept in large groups composed of different species and sizes and in more or less unnatural enclosures.
Healthy, sexually mature pairs of crocodiles are usually not enough to start a breeding program. Genetic diversity to maintain a long-term breeding group must be considered, and certain environmental factors are vital for success. The distinct size and age classes of a free-living population must also be taken into consideration. Optimal sex ratios for breeding in enclosed compounds must be determined and adhered to. If a breeding unit is not based on regard for the animals' basic needs for space, nesting sites, and retreats, the larger specimens will disturb, injure, and often kill smaller specimens.
Diseases and Parasites
Disease symptoms may be easily overlooked if the observer is not familiar with the behavior of crocodiles under a variety of conditions. It is essential to know how they normally walk, swim, sleep, feed, and bask in relation to the time of day, the air and water temperatures, and the amount of sunlight or rain, by day, by night, and at different seasons of the year. Caretakers should notice the appearance of feces from healthy animals to be able to detect evidence of diarrhea, and to identify misaligned teeth and weakened limbs to detect nutritional deficiencies. Eggs are critically dependent on specific temperature and moisture requirements if the embryos are to develop normally.
It is often difficult to determine the cause of illness or death, and even if the ailment has been correctly diagnosed, it is not easy to capture and administer drugs to large numbers of sick animals. Some animals may be injured during the handling process. Emphasis on preventing disease, rather than curing it, is the best way of ensuring a healthy crop.
Almost inevitably, the water in the pools will harbor concentrations of bacteria such as salmonella. If strict hygiene is observed, however, the bacterial level will not be harmful.
It is recommended that whenever possible animals found newly dead should be dissected and vital organs such as the brain, heart, lung, liver, spleen, kidney, and stomach removed for veterinary research. Blood slides should also be taken and feces samples collected. The various specimens must be carefully labeled, frozen as quickly as possible, and packed on ice in a vacuum flask for immediate dispatch to the nearest veterinary research institute or pathologist. Alternatively, dying animals may be sent live for research purposes.
It is helpful for the handler to become thoroughly acquainted with the animal's internal anatomy, in order to distinguish between healthy and diseased organs. This knowledge, coupled with the symptoms noted before the animal dies, and the veterinary report, will be useful in future diagnosis and treatment.
One problem for the crocodile farmer is a roundworm (nematode) parasite that burrows into the belly skin. When the burrow collapses it produces an undulating track across the belly and throat scales that ruins the hide. These parasites have been found in crocodiles from Latin America, Africa, Australia, Papua New Guinea, and Asia. They seem more prevalent in some areas and some farms than in others. The organism has been identified, but no treatment or control has been discovered. It is, however, believed that damp, muddy conditions foster the nematode, and that to reduce it pens should have areas of dry land where the animals can bask.
Killing, Skinning, and Tanning
Some farmers kill the crocodiles themselves, but many rear the animals and then sell them to a larger concern that is better equipped to deal with the skins. Killing is done most quickly and humanely by catching the crocodile with a noose and severing the spinal cord just behind the skull.
Many hides are ruined or severely damaged during skinning. Even a single hole resulting from a slip of the skinning knife may reduce a hide's value by 25 percent.
After skinning, the hides are normally coated with about 0.5 cm of coarse salt and rolled up. Within 48 hours they are unrolled and resalted. If the hide is not sufficiently salted, it may become infected with bacteria or fungi that cause the epidermis of the scales to decay or slip. Although this layer is removed during tannage, scale slip is a symptom of rot and usually causes damage to the finished hide product. If the decay is intense, the salted hides may become reddish or brown in color. This is called "red heat."
Although salt remains the universally used preservative for raw hides, the reptile leather industry has developed chemical fixatives that are used in addition to salt for preserving hides for tanning. Most of these pretannage fixatives are liquid and require soaking the hide in a vat, which may not be feasible in remote areas.
A pretanned hide is called a crust. It is green-gray (chrome tanned) or tan (vegetable tanned) and is stiff. The hide is dyed and glazed to its final finish. To increase the workability and to remove as many of the osteoderms as possible (if they are present), the underside of the hide is shaved to an even thickness. The shaving is done by craftsmen. If they shaved too much, the hide will be thin and weak, especially over the suture between the scales.
General information on the management and status of crocodiles can be found in the following:
IUCN/Crocodile Specialist Group Newsletter. Available from the editors, Peter Brazaitis and Myrna Watanabe, c/o New York Zoological Park, Bronx Zoo, The Bronx, New York 10460, USA.
A Field Guide of Captive Rearing and Management of Crocodiles in India is available from Mr. R. K. Rao, Director, Central Crocodile Breeding and Management Training Institute (Government of India), Hyderabad, Andhra Pradesh, India.
Blake, D. K. 1974. The rearing of crocodiles for commercial and conservation purposes in Rhodesia. The Rhodesia Science News 8(10):315-324.
Blake, D. K., and J. P. Loveridge. 1975. The role of commercial crocodile farming in crocodile conservation. Biological Conservation 8(4): 261-272.
Bolton, M. 1981. Crocodile Husbandry in Papua New Guinea. Field Document 4. FO: DP/ PNG/74/029. Food and Agriculture Organization of the United Nations, Rome, Italy. 103 pp.
Bolton, M., and M. Laufa. 1982. The crocodile project in Papua New Guinea. Biological Conservation 22:169-179.
Brazaitis, P. (In press) Problems in the Identification of Commercial Crocodilian Hides and the Effect on Law Enforcement. Proceedings of the IUCN Crocodile Specialist Group meeting in Zimbabwe September-October, 1982. International Union for the Conservation of Nature and Natural Resources, Gland, Switzerland.
Brazaitis, P. 1973. The identification of living crocodiles. Zoologica 58(3-4):59-101.
Cott, H. B. 1954. Ecology and economic status of the crocodile in Uganda. Record of the Symposium on African Hydrobiology and Inland Fisheries, Committee on Technical Cooperation for Africa South of the Sahara 6:119-122.
Cott, H. B. 1961. Scientific results of an inquiry into the ecology and economic status of the Nile crocodile (Crocodylus niloticus) in Uganda and Northern Rhodesia. Transactions of the Zoological Society of London 29(4):211-337.
Downes, M. C. 1978. An explanation of the National Policy for the Crocodile Programme. Wildlife Division, Department of Lands, Surveys and Environment, Konedobu, Papua New Guinea.
Fuchs, K., nd. Die Krokodilhaut Eduard Roether Verlag Darmstadt, Frankfurt, West Germany.
Graham, A., 1981. Mapping the pattern of crocodile nesting activity in Papua New Guinea. Field Document No. 3, FO: DP/PNG/74/029. Food and Agriculture Organization of the United Nations, Rome, Italy. 50 pp.
Joanen, T., and L. McNease. 1975. Notes on the Reproductive Biology and Captive Propagation of the American Alligator. Proceedings of the 29th Annual Conference of the Southeastern Association of Game and Fish Commissioners 29:407-415.
Joanen, T., and L. McNease. 1979. Culture of the American alligator. International Zoo Yearbook 19:61-66.
King, F. W., and P. Brazaitis. 1971. Species identification of commercial crocodile skins. Zoologica 56(2): 15-72.
Loveridge, J. P. ed. 1982. The Zimbabwe Science News 16(9):196-219. Causeway, Zimbabwe. (Contains five articles on crocodilian research and conservation; from Zimbabwe, Australia the United States, and lndia.)
Millichamp, N. J. ;980. Medical aspects of disease in reptile collections. In The Care and Breeding of Captive Reptiles, The British Herpetological Society, London, England.
Parker, F. 1981. New Crocodile Laws for Papua New Guinea. Division of Wildlife, Department of Lands and Environment, Konedobu, Papua New Guinea. 50 pp.
Pooley, A. C. 1969. Some observations on the rearing of crocodiles. Lammergeyer 10:45-59.
Pooley, A. C. 1971. Crocodile rearing and restocking. Pp. 104-130 in Crocodiles, IUCN Publications New Series Supplementary Paper 32. International Union for Conservation of Nature and Natural Resources, 1110 Gland, Switzerland.
Pooley, A. C. 1973. Conservation and Management of Crocodiles in Africa. Journal of the South African Wildlife Management Association 3(2):101-103.
Pooley, A. C. 1977. A report on Crocodile Farming. Papua New Guinea. Wildlife leaflet No. 77/27. pp. 1-14.
Pooley, A. C. 1981. Disappearing African Crocodiles. Oryx 16(1):38-40.
Pooley, A. C. (In press). The status of crocodiles in Africa. Paper Presented at 5th Meeting IUCN Survival Service Commission's Crocodile Specialist Group. Gainesville Florida, USA. September 1980.
Pooley, A. C., and C. Gans. 1976. The Nile crocodile. Scientific American 234(4): 114-124.
Wallis, B. E. 1980. Market prospects for reptile leathers. Report number ITC/DIP/12, International Trade Commission, Geneva, Switzerland. 50 pp.
Wermuth, Von H., and K. Fuchs. 1978. Bestimmen von Krokodilen und ihrer Haute. Gustav Fischer Verlag, Stuttgart, New York.
Whitaker, R. 1982. Export prospects from commercial crocodile farms in Bangladesh. ITC/UNCTAD, Geneva, Switzerland. 47 pp.
Whitaker, R., and M. Kemp. 1981. The crocodile industry in Papua New Guinea: Commercial Aspects. Field Document No. 2. FO:DP/PNC/74/029. Food and Agricultural Organization of the United Nations, Rome, Italy. 35 pp.
The following individuals are involved in crocodilian research. Most are biologists concerned with the conservation or natural history of the animals.
Applied Ecology Crocodile Farm, Edward River, Queensland 4870
Shelley Burgin, Total Environment Center, 18 Argyle Street, Sydney, New South Wales 2000
Melvin Bolton, Woodbury Farm, Woodbury Road, M.S. 142, Via Yeppoon, Queensland 4703
Max C. Downes, The Game Conservation Center, 24 Queens Parade, North Fitzroy, Victoria 3068
Alistair Graham, P.O. Box41266, Darwin, Northern Territory 5792
Gordon Grigg, Zoology A08, University of Sydney, Sydney, New South Wales 2006
John Lever, Koorana Crocodile Farm, M.S.F. 76, Rockhampton, Queensland 4702
Harry Messel, Head, School of Physics, University of Sydney, Sydney, New South Wales 2006
Fred Parker, 717 Ross River Road, Kirwan, Queensland 4814
Grahame Webb, School of Zoology, University of New South Wales, Kensington 2033
Mohd. Reza Khan, Assistant Professor, Department of Zoology, University of Dacca, Dacca 2
William Magnusson, Depto de Ecologia, Instituto Nacional de Pesquisas da Amazonia, Caixa Postal 478, 69000, Manaus, Amazonia
Ko Ko Gyi, Professor of Zoology, Rangoon Arts and Sciences University, Rangoon
Nyan Taw, Research Officer, People's Pearl and Fishery Corporation, Myakhwanyo Street, Thaketa, Rangoon
People's Republic of China
Huang Chu-Chien, Institute of Zoology, Chinese Academy of Science, Beijing
The Swatow Prefecture Crocodile Farm, Shantou, Guang Dong Province
Federico Medem, Instituto Roberto Franco, Apartado Aereo 2261, Villavicencio (Meta)
Gerado Budowski, Head, Natural Renewable Resources Programme, CATIE, Turrialba
Luis Varona, Norte 29, Nuevo Vedado, La Habana 6
Jose Alberto Ottenwalder, Museo Nacional de Historia Natural, Plaza de la Cultura, Santo Domingo
Federal Republic of Germany
Karlheinz Fuchs, Schillerstrasse 2, 6257 Hunfelder 2
Jaime Tres 1., Centro de Estudias Conservacionistas, Universidad de San Carlos de Guatemala, Avenida de la Reforma 0-63, Zona IO, Guatemala
B. C. Choudhury and Lala A. K. Singh, Central Crocodile Breeding and Management Training Institute, 19-4-319, Lake Dale, Rajendranagar Road, Hyderabad 500 264, Andhra Pradesh
Indian Board for Wildlife, c/o Department of Environment, Bikaner House, Shahjahan Road, New Delhi 110 011
John Sale, UNDP/FAO Crocodile Breeding and Management Project, 19-4-319, Lake Dale, Rajendranagar Road Hyderabad 500 264, Andhra Pradesh
S. Shanmugunathan, Chief Wildlife Warden, Vivekananda Road, Coimbatore, Tamil Nadu
Sudhakar Kar, Saltwater Crocodile Research and Conservation Unit, Danginal 754 220 Via Rejkanika, District Cuttack, Orissa
Romulus Whitaker, Madras Snake Park Trust, Guindy Deer Park, Madras, Tamil Nadu, 600 002
G. S. Child, Wildlife and Parks Management Of ficer FAO, Rome
Wataru Kimura, Proprietor, Atagawa Tropical and Alligator Garden, Atagawa Higashi Zlu Town, Shizuoka Prefecture
R.D. Haller , Bamburi Portland Cement Co. ,Ltd., P.O. Box 90202 ,Mombasa
Paul R. Wycherley, President, Malayan Nature Society, P.O. Box 150, Kuala Lumpur
Miguel Alvarez del Toro, Director, Instituto de Historia Natural, Departamento de Zoologia, Apartado Postal No. 6, Tuxtle Gutierrez, Chiapas, 29000
Marco Antonio Lascano B., INIREB, Apdo. No 281, Merida
Tirtha Maskey, National Parks and Wildlife Conservation Office, Thapathali, P.O. Box 107, Kathmandu
Antoon de Vos, Box 34, Whitford, Auckland
Milton G. Camacho B., Instituto Nicaraguense de Recursos Naturales y del Ambiente (IRENA), Depto. de Fauna Silvestre, Kim 12 1/2 Carreterra Norte, Managua.
Ashiq Ahmad, Wildlife Management Specialist, Pakistan Forest Institute, Peshawar
Abdul Latif Rao, Conservator of Wildlife, National Council for Conservation of Wildlife, Ministry of Food and Agriculture, U.G. St. 51, Sector F 6/4, Islamabad
Papua New Guinea
Miro Laufa, Division of Wildlife, Department of Lands and Environment, P.O. Box 2585, Konedobu
Karol Kisokau, Director, Office of Environment and Conservation, Central Government Offices, Waigani
Navu Kwapena, Division of Wildlife, Department of Lands and Environment, Konedobu
Graham Goudie, Crocodile Farm, Lae
Martin Hollands, Monitoring Ecologist, National Crocodile Project, P.O. Box 2585 Konedobu
Pedro Vasques Ruesta, Departamento de Manejo Forestal, Universidad Nacional Agraria, Apdo. 456, La Molina
Angel C. Alcala, Division Research, Extension and Development, Silliman University, Dumaguete City, 6501, Negros
School of Agriculture, Silliman University, Dumaguete City, 6501, Negros.
H. B. Anthony, The Natal Parks, Game and Fish Preservation Board, Box 662, Pietermaritzburg, Natal
Antony Pooley, P.O. Box 42, St. Lucia Estuary, 3936 Zululand
Rene E. Honegger, Curator, Zurich Zoo, Zurichbergstrasse 221, 8044 Zurich
U. Srisomboon, Ministry of Agriculture, Department of Livestock Development, Bangkok Utai Youngprapakorn and Charoon Youngprapakorn, The Samutprakan Crocodile Farm and Zoo Co., Ltd., Talban Road, Samutprakan
Angus d'A. Bellairs, Department of Anatomy, St. Mary's Hospital Medical School University of London, Paddington, London W2
H. Robert Bustard, Isle of Man
John Behler, New York Zoological Society, 185th Street & Southern Blvd., The Bronx, New York 10460
Peter Brazaitis, New York Zoological Society, 185th Street & Southern Blvd., The Bronx New York 10460
Gary Callis, Rt. I, Box 360, Clayton, New Mexico
Robert H. Chabreck, Louisiana State University, School of Forestry and Wildlife Management, Baton Rouge, Louisiana 70803
Michael Davenport, Department of Herpetology, National Zoological Park, Smithsonian Institution, Washington, D.C. 20008
Claire Hagen, Representative, Reptile Products Association, 120 Cabrini Blvd., New York, New York 10033
Fred Hauptfuhrer, Director of Planning and Development, World Wildlife Fund, Inc., 910 17th Street NW, Washington, D.C. 20006
Howard Hunt, Atlanta Zoological Park, 518 Atlanta Ave. S.E., Atlanta, Georgia 30315
Ted Joanen, Rockefeller Wildlife Refuge, Route 1, Box 20-B, Grand Chenier, Louisiana 70643
F. Wayne King, Director, Florida State Museum, Gainesville, Florida 32611
Jeffrey W. Lang, Biology Department, University of North Dakota, University Station, Grand Forks, North Dakota 58202
Charles J. Lankester, UNDP, I United Nations Plaza, New York, New York 10017
James H. Powell, 1110 Kokomo Street, Plainview, Texas 79072
Charles A. Ross, Division of Reptiles and Amphibians, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560
Myrna Watanabe, 141 Columbia Heights, Brooklyn, New York 11201
Federico Achaval, Departamento de Zoologia (Vertebrados), Universidad de la Republic Cerrito73, Montevideo
Tomas Blohm, Apartado 69, Caracas 1010-A
Andres Seijas Y., Servicio Nacional de Fauna Silvestre, MARNR, Apartado 184, Maracay
D. K. Blake, Department of National Parks and Wildlife Management, P.O. Box 8365, Causeway, Harare
John Loveridge, Zoology Department, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare
Kevin van Jaarsveldt, Crocodile Farmers Association of Zimbabwe, P.O. Box 2569, Harare
EDWARD S. AYENSU, Director of the Office of Biological Secretary General Smithsonian Institution, Washington, D.C., is currently the Secretary General of the International Union of Biological Sciences. He received his B.A. in 1961 from Miami University in Ohio, M.Sc. from The George Washington University in 1963, and his Ph.D. in 1966 from the University of London. His research interests are in comparative anatomy and phylogeny of flowering plants, commercial timbers, histology of monocotyledons, economic botany, and tropical biology. An internationally recognized expert on tropical plants, he has published extensively in these areas and on topics relating to science, technology, and development, especially in developing countries. Dr. Ayensu was co-chairman of the Panel on Underexploited Tropical Plants of the Advisory Committee on Technology Innovation and chairs and serves as a member of many international bodies.
ARCHIE F. CARR, JR., is Graduate Research Professor in the Department of Zoology, University of Florida, Gainesville. As Technical Director of the Caribbean Conservation Corporation, he has directed a seasonal research program at the breeding ground of the green turtle at Tortuguero, Costa Rica, since 1952, with continuous grants from the National Science Foundation from 1955 to 1980, and has carried out investigations of marine turtle ecology and navigation in various parts of the world. The author of numerous papers, articles, and books, he received the Daniel Giraud Elliot Medal of the National Academy of Sciences for Handbook of Turtles and the John Burroughs Medal for The Windward Road. He is Research Associate of the American Museum of Natural History; Affiliate Curator of Natural Sciences, Florida State Museum; Chairman of the Marine Turtle Specialist Group of the Survival Service Commission, International Union for the Conservation of Nature; Honorary Consultant of the World Wildlife Fund; Fellow of the Linnean Society of London; Fellow of the American Fisheries Society; and a member of Phi Beta Kappa and Sigma Xi.In 1973 he was awarded a gold medal from the World Wildlife Fund for the application of scientific findings to the conservation of marine turtles. In 1975 he received the Edward W. Browning Award for achievement in biological conservation. In 1978 Dr. Carr was awarded the Gold Medal of the New York Zoological Society for contributions to natural science and conservation; in 1978 he became Officer of the Order of the Golden Ark (The Netherlands).
F. WAYNE KING is the Director of the Florida State Museum, Gainesville. He received a B.S. in 1957 and an M.S. in 1961 from the University of Florida and a Ph.D. from 1966 from the University of Miami. His research interests are in wildlife conservation and habitat preservation, impact of international trade on wildlife populations, and ecology and behavior of reptile populations. He worked at the New York Zoological Society from 1967 to 1975. As an international wildlife consultant, Dr. King has received honors from the Dominican Republic, the American Association of Zoological Parks and Aquariums, and from H.R.H. Prince Bernhard of The Netherlands. He has served on committees advising the State Department and the International Union for Conservation of Nature and Natural Resources on policies regarding the trade of crocodile skins, turtle products, and other wildlife materials.
FRANCOIS MERGEN, Pinchot Professor of Forestry and Professor of Forest Genetics, Yale University, was Dean of the School of Forestry and Environmental Studies at Yale from 1965 to 1975. He received a B.A. from Luxembourg College and a B.Sc.F. from the University of New Brunswick in 1950, an M.F. in ecology in 1951, and a Ph.D. in forest genetics from Yale in 1954. He is especially knowledgeable about francophone Africa and was chairman of the Sahel program of the Board on Science and Technology for International Development and a member of the Advisory Committee on Technology Innovation. From 1960 to 1965 he was research collaborator at the Brookhaven National Laboratory. In 1966 he was the recipient of the Award for Outstanding Achievement in Biological Research from the Society of American Foresters and in 1975 was Distinguished Professor (Fulbright-Hays Program) in Yugoslavia. Before joining the Yale faculty, he served as project leader in forest genetics for the U.S. Forest Service in Florida. He has served as a consultant to FAO, various foreign governments, and private forestry companies, and he has traveled extensively in the tropical countries of Asia, Africa, and Latin America.
MICHAEL G. MORRIS is head of the Furzebrook Research Station of the Institute of Terrestrial Ecology (National Environment Research Council, U.K.). He received a B.A. in natural sciences (zoology) at the University of Cambridge of 1958, M.A. in 1962, and received his Ph.D. from London University in research on the integrated control of orchard pests. Dr. Morris worked at Monks Wood Experimental Station on the effects of grassland management on populations of invertebrates and developed a strong interest in community and applied ecology, particularly the conservation of insect populations. Recently he has become involved with problems of butterfly conservation and resource utilization. He is Secretary of the Joint Committee for the Conservation of British Insects, a Vice-Chairman of the Lepidoptera Specialist Group of lUCN'S Survival Commission, and Chairman of the Habitat and Species Protection Committee of SEL (Societal Europaea Lepidoptero-Logica).
HUGH L. POPENOE is Professor of Soils, Agronomy, Botany, and Geography and Director of the Center for Tropical Agriculture and International Programs (Agriculture) at the University of Florida. He received his B.S. from the University of California at Davis in 1951 and his Ph.D. in soils from the University of Florida in 1960. His principal research interest has been in the area of tropical agriculture and land use. His early work on shifting cultivation is one of the major contributions to this system. He has traveled and worked in most of the countries in the tropical areas of Latin America, Asia, and Africa. He is past Chairman of the Board of Trustees of the Escuela Agricola Panamericana in Honduras, Visiting Lecturer on Tropical Public Health at the Harvard School of Public Health, and a Fellow of the American Association for the Advancement of Science, the American Society of Agronomy, the America Geographical Society, and the International Soils Science Society. He is Chairman of the Advisory Committee for Technology Innovation and a member of the Board on Science and Technology for International Development.
ROBERT MICHAEL PYLE, a writer and consulting lepidopterist based in Gray's River, Washington, has served since 1979 as Co-Compiler of the lUCN Invertebrate Red Data Book. In this capacity he is consultant to the Conservation Monitoring Center in Cambridge, England. After receiving his B.S. and M.S. at the University of Washington, he took his Ph.D. through the School of Forestry and Environmental Studies at Yale University in 1976. He worked for the Government of Papua New Guinea on the conservation and utilization of insect resources and then with the Nature Conservancy as Northwest Land Steward. A former Fulbright Scholar to the United Kingdom, Dr. Pyle subsequently founded the Xerces Society for conservation of beneficial insects and their habitats. He has been chairman of IUCN'S Lepidoptera Specialist Group (Species Survival Commission) since 1976. His publications include the Audubon Society Field Guide to North American Butterflies. A comprehensive book on insect conservation in his next project.
SHELDON R. SEVERINGHAUS received his Ph.D. from Cornell University in 1977 in natural resources management. He has worked on various wildlife research projects in Asia since 1964 and is representative for the Asia Foundation in Taiwan. He has published articles on butterfly conservation and wildlife industries in Taiwan, where he has been studying the butterfly and wildlife farming projects.
NOEL D. VIETMEYER, staff officer for this study, is Professional Associate of the Board on Science and Technology for International Development. A New Zealander with a Ph.D. in organic chemistry from the University of California, Berkeley, he now works on innovations in science that are important for developing countries.