close this bookMicrolivestock - Little-Known Small Animals with a Promising Economic Future
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View the documentAcknowledgments
View the documentPreface
View the documentIntroduction
close this folderPart I : Microbreeds
View the document1 Microcattle
View the document2 Microgoats
View the document3 Microsheep
View the document4 Micropigs
close this folderPart II : Poultry
View the document5 Chicken
View the document6 Ducks
View the document7 Geese
View the document8 Guinea Fowl
View the document9 Muscovy
View the document10 Pigeon
View the document11 Quail
View the document12 Turkey
View the document13 Potential New Poultry
close this folderPart III : Rabbits
View the document14 Domestic Rabbit
close this folderPart IV : Rodents
View the document15 Agouti
View the document16 Capybara
View the document17 Coypu
View the document18 Giant Rat
View the document19 Grasscutter
View the document20 Guinea Pig
View the document21 Hutia
View the document22 Mara
View the document23 Paca
View the document24 Vizcacha
View the document25 Other Rodents
close this folderPart V : Deer and Antelope
View the document26 Mouse Deer
View the document27 Muntjac
View the document28 Musk Deer
View the document29 South America's Microdeer
View the document30 Water Deer
View the document31 Duikers
View the document32 Other Small Antelope
close this folderPart VI : Lizards
View the document33 Green Iguana
View the document34 Black Iguana
close this folderPart VII Others
View the document35 Bees
close this folderAppendixes
View the documentA Selected Readings
View the documentB Research Contacts
View the documentC BIOGRAPHICAL SKETCHES OF PANEL MEMBERS
View the documentBoard on Science and Technology for International Development (BOSTID)

26 Mouse Deer


Lesser Malayan Deer

Mouse deer1 (Tragulus spp. and Hyemoschus aquaticus) are among the smallest ruminants known. The lesser mouse deer of Southeast Asia is probably the smallest; an adult stands only 20 cm high and weighs a merc 1-2.5 kg.

Although they look vaguely like tiny deer, mouse deer differ in several particulars. The stomach is simpler and (like the camel's) has three instead of four effective compartments. Rumination occurs, but mouse deer are the most primitive of all ruminants. Indeed, they share a number of characteristics with nonruminants, including lack of horns or antlers; continually growing, tusklike upper canines in males; sharp-crowned premolars; and four fully developed toes.

Virtually unchanged in 25 million years of evolution, these are solitary, nocturnal, retiring animals that have seldom received detailed research. Whether they might make suitable microlivestock is unknown. However, they seem to be tractable, and people in Southeast Asia (Sarawak, for instance) have traditionally kept at least one of the species as backyard pets. Moreover, mouse deer are indigenous to tropical lowland regions and withstand the heat and humidity that are stressful to most conventional livestock species. They probably also are resistant to many diseases of those torrid regions.

In the United States, mouse deer are being raised as laboratory animals for basic research on ungulates. This is because the animals are easier to handle than large deer or goats.2

APPEARANCE AND SIZE

 

 

Mouse deer are graceful, lithe, and look somewhat like large rodents. The Asian species are the shape and size of an agouti (see page 198); the African species is more like the pace (see page 262). All have short legs, a small head, and a pointed snout. Adults weigh from 1 to 5 kg, depending on species. The head and body are only 04-1 m long, and the shoulder height is merely 20-36 cm. Males are generally smaller than females.

In most species the body is a rich brown with white spots and stripes. The belly is usually white. The animals stand on the middle toes, so that the lateral ones do not touch the ground. Neither sex bears antlers. In males the upper canines form long tusks that may extend outside the lips and even to below the line of the jaw.

DISTRIBUTION

 

Twenty-five million years ago, early forms of mouse deer existed throughout Asia, Africa, and Europe. Today's species are restricted to tropical forests and mangrove thickets of Southeast Asia and Central Africa.

Of the three Asian species, the Indian mouse deer occurs in southern India and Sri Lanka; the larger Malayan mouse deer occurs on the mainland of Southeast Asia and the lesser Malayan mouse deer occurs on Java as well. The water chevrotain, a related African animal, is found from eastern Zaire to the Atlantic coast.


figure


Range of water chevrotain .

STATUS

 

In recent years, human encroachment into the forest has caused the destruction of the mouse deer habitats and has put various mouse deer species under a pressure that is causing their populations to decline.

HABITAT AND ENVIRONMENT

 

These animals inhabit equatorial forests and mixed secondary tropical forest. They generally live among undergrowth on the edges of dense lowland rainforests. They especially haunt rivers and swampy bush areas, seeking escape by water when in danger.

BIOLOGY

 

Little about these animals is recorded. Essentially vegetarians, they feed chiefly on fruits, supplemented by leaves. They also eat insects (for instance, ants), if available. They do not seem to eat grass.3

The premolars of the mouse deer are designed for piercing and chopping food rather than for chewing. As noted, the stomach consists of three functional compartments: the rumen, the reticulum, and the abomasum. (The omasum of ruminants is represented only by a rudimentary area.) The stomach occupies almost the whole of the abdominal cavity, extending from the diaphragm to the pelvic inlet, which provides this small animal with large food-storage capacity.

The blood has a very high erythrocyte (red blood corpuscle) count as well as the smallest erythrocyte size of any mammal. The flesh is "white" and the muscles contain little myoglobin.

Mature females reproduce almost continuously, and usually regardless of season. In the female larger Malayan mouse deer, mating occurs within 2 days of giving birth. In the African species, many births are synchronized with the rainy seasons, when fruits are plentiful. The gestation period is about 5-6 months, depending on the species. There is only one young per birth. Weaning normally occurs at 2-3 months, but can occur as early as 3 weeks, with sexual maturity achieved at 4-5 months (Asian species) and 10 months (African species). The young stay alone, hidden in vegetation during the first month or two.

BEHAVIOR

 

Mouse deer are shy, keeping to dense jungle and depending on concealment for protection. Although often present in large numbers, they are seldom seen. Preferring to be near lakes, rivers, or streams, they can nevertheless wander I km or more from water. They feed mostly at dusk or at night, sheltering in undisturbed areas or under shady bushes during the day. They utter weak, bleating sounds, and when frightened, jump a meter or more in the air.

Communication is by scent and calls. The African species possess anal and preputial glands, with which, along with urine and feces, they mark their home ranges. Males of both Asian and African species possess a chin gland to mark either the vegetation or their mates.

Mouse deer are among the most excitable, nervous, and jumpy animals. One must tread softly in their presence for fear of causing absolute pandemonium and mishap.

USES

 

Mouse deer are widely sought by native people for food, and their meat is highly regarded. Dressed carcasses have a high proportion of muscle (84 percent in Asian species), low proportion of bone (15 percent), and an insignificant amount of fat. The ratio of muscle to bone is large - 5.6:1. The mean dressing percentage of 62.1 percent is greater than that reported for cattle, water buffalo, or goat.5

HUSBANDRY

 

Adults are wild, generally intractable, and "flighty," but young animals (at least of the Asian species) tame readily and make good pets. Nevertheless, these are delicate creatures and must always be handled gently. Individuals caught in the wild tend to bash against the sides of cages.

Despite an unpromising temperament, Asian mouse deer are regularly bred in zoos, including those in Amsterdam, New York, and Zurich. They also have been reared successfully in small enclosures at several research institutes, such as the I.R.E.T. Institute, Makokou, Gabon; the Institute of Medical Research in Kuala Lumpur, Malaysia; and at Fort Detrick in the United States.

Perhaps the best way to breed this animal is by using the battery system of small units comprising one male and two females per cage. The costs are mostly for obtaining suitable enclosures and for feeding and watering troughs.6 The cages must be covered with mesh because the mouse deer can jump. However, the covering must be sufficiently high to allow the male to stand with its body vertical during copulation.7 They can be fed a variety of foods and grow well on stems of bean plants.

ADVANTAGES

 

As noted, these are small, seemingly tractable creatures that are at home in the heat, humidity, and diseases of tropical lowlands. They might play a particularly important role as livestock for tropical rainforests; the forests could be left standing while the animal still produces meat. Today, in a widely condemned process, tropical rainforests are being felled in order to raise cattle for meat.

LIMITATIONS

 

Small size makes mouse deer easy prey for various predators. In the wild, snakes, crocodiles, eagles, and forest cats feed on them.

Mouse deer are among the most excitable, nervous, and jumpy animals. One must tread softly in their presence for fear of causing absolute pandemonium and mishap.

The different species are solitary, and it is difficult to keep many individuals (especially males) in a restricted space. They must be kept in a quiet enclosure, with cover or good shelters.

RESEARCH AND CONSERVATION NEEDS

 

The survival of these four "living fossils" depends on conserving their rainforest habitat and restricting hunting, especially night hunting. But studies of their propagation and management are also imperative.

In particular, research is warranted on various aspects of their husbandry, such as enclosure design, space requirements, and health. A special research need is to understand the animal's nutritional requirements and to develop diets for use in captivity.

 

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