|Auburn University Digital Library|
|Microlivestock - Little-Known Small Animals with a Promising Economic Future|
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|Part VI : Lizards|
The work on green iguana husbandry may apply also to the black iguanas' (Ctenosaura similis, C. acanthura, C. hemilopha, and C. pectinata). These are similar lizards that live in dry habitats throughout Central America
Exploitation of wild black iguanas for food began in ancient times and has continued in most places over hundreds of years without much harm to the natural populations. Until the 1970s, Latin Americans could obtain the meat and eggs with little effort, and the animals sold cheaply in city markets. In recent years, however, the lizards have become scarce and prices have risen sharply. For instance, in 1976 the central market of San Salvador was selling large specimens for the equivalent of 80 cents, but by 1979 prices were generally from three to six times as much. Today, black iguana meat costs more than fish, poultry, pork, or beef.
Eating small game animals is deeply rooted in the traditions of Central America and cannot readily be changed by legislation or education. Despite official edicts, campesinos on a subsistence diet will not willingly forego the little meat they get by capturing and eating lizards. Moreover, legislation is seldom effective because there are too few enforcement officials.
As with the green iguana, it seems likely that when the factors causing hatchling mortality are reduced, a large harvestable annual surplus can be produced. Black iguanas efficiently convert vegetation into high-grade protein suitable for human consumption. Young ones, however, are insectivorous and carnivorous rather than purely herbivorous, and during their first weeks of life may require a more expensive diet (perhaps meat scraps) than green iguanas require. Moreover, most insectivorous lizards require moving prey. They may or may not accept meat scraps as food.
APPEARANCE AND SIZE
Black iguanas are smaller and more stocky than green iguanas, but weigh up to 3 kg. Their tails are spiny and short. The scales on the tail are enlarged, grow in spirals, and are sharp-pointed. Other than that (apart from being generally greyish black in color), the two animals are similar in appearance.
The different black iguana species range from northern Mexico along both coasts of Central America to Panama and Colombia's Caribbean islands. Most tolerate moderate human presence well, often thriving around town garbage dumps and cemeteries.
As recently as 1981, black iguanas were shipped to markets by the truckload. Today, they are generally limited or even absent over much of their original range. Nevertheless, they are still the major game animals across extensive areas of Central America. Many of those taken are gravid females, which is disastrous for the populations. Excessive insecticide spraying is also thought to be reducing their populations in some areas.
HABITAT AND ENVIRONMENT
Black iguanas thrive in dry, open woodland. They particularly like rocky hillsides, for they depend for shelter on crevices, rock piles, or soft soil in which they dig burrows.
These omnivores feed on foliage, flowers, and fruits, but also on insects and small vertebrates. Adults spend some of their time climbing trees, but they are much less arboreal than green iguanas. Hatchlings are initially terrestrial but have a mostly arboreal stage in their early weeks of life.
Females lay one clutch of 20-90 eggs each year. The eggs are much smaller than those of the green iguana and therefore are not as popular a food.
These lizards live in burrows or in holes in trees. A typical burrow has several entrances and is 1-2 m long. Several females may combine efforts to form a complex communal burrow with several individual nest chambers. They are such diligent diggers that many are caught while absorbed in the task of adding a new room.
In some places, even where they are not common, black iguanas are still intensively hunted. Because their meat is valuable, the reward justifies the considerable effort involved in finding and killing them. Hence, where populations are so depleted that organized hunting is unprofitable, the animals are still subjected to relentless destruction by individuals.
Farming black iguanas is a novel idea. However, it is not a foolish one. In 1981 the Centro de Recursos Naturales (CENREN) in El
Salvador started a black iguana farming project. Since then, its researchers have collected data on growth rates, feeding patterns, and the maintenance and reproduction of captive adults. The program offers some promise of maintaining breeding stock in large outdoor enclosures, of producing large numbers of hatchlings, and of restocking depleted areas.
Other iguanas that deserve consideration for husbandry include the rock (rhinoceros) iguana (Cyclura cornuta), a herbivorous lizard of the Antillean region. This has been raised in considerable numbers at the National Zoo of Santo Domingo, Dominican Republic. Captive-bred specimens have reproduced at the age of 32 months, average clutch size has been about 15, and the average incubation time has been 82 days (at 31ÝC). The innate tameness of these island iguanas renders them better adapted for captive rearing than either the green or the black iguana, and their greater size is an advantage as well. On the other hand, the length of time required to reach maturity, and the relatively small egg clutch (about half that of the green iguana and one-third that of the black iguana) are definite disadvantages.
A related species, Iguana delicatissima, also deserves research and conservation attention. It occurs in the Leeward Islands and Martinique, and (as its specific name implies) is even better eating than the green iguana.
Latins believe that various ailments are cured or benefited by the flesh of these lizards, so they willingly pay much more for their meat than they would for equivalent amounts of other meats. In most places where the two occur together, the black iguana is preferred over the green iguana.
Compared with green iguana, the black iguana reproduces readily in captivity and has an even higher reproductive potential (averaging 43 eggs per clutch). It has the additional advantage that it thrives in deforested and altered habitats. It can survive near human settlements despite the attacks of dogs and cats, and it attains dense populations in suburban lots or open spaces. (It survives even downtown in cities such as Managua, but not in dense populations because dogs, cats, and humans take so many.) Hence, even in towns and cities, there are habitats capable of supporting it.
Black iguanas will feed on weedy vegetation or garbage, and adults seem easier to maintain in captivity than their green iguana counterparts.
The long delay (probably at least two years) before the animals reach marketable size might make it difficult for the grower to compete with common meats such as poultry or fish. Certain parasitic worms can make the flesh inedible.
Although smaller than green iguanas, black iguanas are much more aggressive and will defend what they perceive to be their territory. They can inflict a painful bite. They also tend to escape from captivity more readily.
As noted, these omnivores depend on animal matter during part of their life cycle.
RESEARCH AND CONSERVATION NEEDS
The biology of the black iguana deserves much more study.
Management techniques developed for the green iguana should be tested for their applicability for black iguana species. Harvesting and recruitment schemes must be developed to create sustainable populations in the wild. The specific needs for feeding the young also need to be addressed.
I am convinced that in the Third World, it is only when poor people are assured of their livelihood that they will help us to safeguard their natural environments. So long as people remain hungry, it is very difficult to talk to them about conservation. As a result, I believe that development and conservation are inseparable. Only when conservation takes on a dimension of helping the poor, the downtrodden, the destitute, will it have an enduring impact.
M.S. Swaminathan International Union for Conservation of Nature and Natural Resources
I suspect that wildness is an inherited characteristic as was found for the turkey by Starker Leopold. So in attempting domestication one should expect to have difficulty until there are enough animals that you can select breeding stock for quietness and tractability.
Ian McTaggart Cowan Emeritus Professor of Zoology
University of British Columbia
Cattle will never be extinct for the simple reason that man eats cattle. The best way to preserve wild species is by demonstrating that they, too, can be a valuable resource.
New York Times Magazine
Wildlife utilization should be considered a legitimate form of land use, just as much as livestock husbandry. In fact, what has happened in the past is that Man has domesticated a limited number of animals, mainly in the temperate zones, while overlooking a considerable potential of other animals, which could be domesticated or used with equal validity.
Antoon De Vos