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1 Introduction Crocodiles, alligators, caimans, and gavials* have existed for some 200 million years âmuch longer than mammalsâbut they are now disap- pearing at alarming rates. Of the 21 or so species of crocodilians distrib- uted in the warm waters of the world, at least 18 are threatened with ex- tinction in most of the countries where they are found. Although some species, such as the American alligator, appear to be out of danger because of strict conservation measures, many of the others survive mostly in national parks, protected preserves, or a few breeding stations. This is true for the slender-snouted crocodiles of Africa and Asia, the saltwater crocodile of Australia and Southeast Asia, the black caiman and Orinoco crocodile of South America, the Chinese alligator, the Siamese crocodile, and other species. Habitat destruction is a major contributor to crocodilian decline; each year more breeding areas are disturbed as swamps and marshlands are drained, rivers dammed, estuaries reclaimed, and riverine forests de- nuded. However, illegal poaching by tribal people with their simple but effective traps, snares, and set hooks, as well as professional hunters operating with power boats, spotlights, and modern firearms are also decimating the animals over most of their ranges. To a large extent these animals are being destroyed because of their market value. Crocodile is regarded as the costliest and most fashionable leather in western markets. Since World War II, demand for crocodile leather shoes, handbags, luggage, wallets, watchbands, and other expen- sive luxury articles has far exceeded supply. Even small items such as purses and handbags sell for many hundreds of dollars each. For in- stance, a ladies' purse or handbag made from crocodile skin can com- *Present-day crocodilians are grouped into three families: crocodiles, alligators and caimans, and gavials (gharials). The animals differ from one another only in minor charac- ters such as shape of snout, arrangement of scutes, and dental features. This report focuses mainly on crocodile species, but its conclusions are generally applicable to alligators, caimans, and gavials. 1
2 CROCODILES AS A RESOURCE FOR THE TROPICS mand prices as high as $4,000. A pair of men's shoes may cost from $500 to $900, and a wallet from $150 to $250. The crocodile trade peaked in the mid-1960s, when world markets ab- sorbed more than 2 million crocodile skins each year. Today it is still large. In 1979, for instance, 1,000,000 caiman hides and 300,000 true- crocodile hides entered international commerce. In 1981 the United States itself imported 100,000 hides. International markets for reptile hides and leathers are centered in France, Italy, the Federal Republic of Germany, and Japan. France, the single largest buyer of raw crocodilian hides, uses an estimated 300,000 to 400,000 skins a year. The major buyers of finished crocodile leather products are Hong Kong, Japan, Thailand, Singapore, and the United States. Unrestricted hunting and poaching for hides are wiping out the large breeding animals. Excessive hunting has a devastating effect on crocodile populations because their age distribution is like a pyramid: a small num- ber of breeding animals dominates a large number of juveniles and hatchlings, most of which never survive to maturity. Such societies, in which the size of future populations depends on only a few animals, are highly vulnerable to extinction; once some of the mature members are killed the population can crash. And it takes a long time for a crocodilian population to rebuild because for most large species the females do not begin breeding until they are at least 8 years old. Rearing Crocodiles Although there may seem to be no future for many crocodile popula- tions, the situation is not hopeless. With intelligent intervention and under good conditions they can recover rapidly. Mature crocodiles have no enemies other than man, and, given some care and protection, a small number of breeders can produce a huge number of progeny each year. Mature females of the various crocodilian species usually lay between 30 and 70 eggs each year, and under normal conditions most of these eggs hatch successfully. The key to conserving the population is to protect the few mature animals and their habitats. Then, because of their fecundity, crocodilians can rapidly build up large numbers of young. This has been exemplified by the American alligator (Alligator missis- sippiensis). Ten years ago its future seemed doubtful, but the legal pro- tection of the populations has brought a remarkable recovery. Numbers are now so high that two states have lifted the ban on harvesting alliga- tors, and between 10,000 and 20,000 American alligator hides now enter commerce each year. The past few decades have seen several other examples of successful
INTRODUCTION 3 crocodile-rearing projects. Later chapters of this book highlight the na- tional program in Papua New Guinea. In addition, three successful government-operated farms exist in India (where all the progeny is returned to the wild because current Indian law prohibits commercial crocodile farms). A remarkable farm with more than 3,000 breeding ani- mals operates on the outskirts of Bangkok, Thailand. Australia has four crocodile farms, and a few African countries now have crocodile farms that are already beginning to supply hides internationally. For example, in 1982 Zambia had two such farms, Zimbabwe, five, South Africa, four (with five more planned or under construction), and Kenya, one. Appen- dix A lists these and other countries that are initiating farms for various crocodilian species. The early technical success of these projects offers the expectation that with an appropriate framework of safeguards and research, crocodiles might become a thriving resource for tropical nations. If such experi- ences can be replicated, crocodilians and their habitats may come to be considered as resources to be managed and treasured. This will require considerable investment, strict legislation and law enforcement, and international cooperation and research, as well as careful monitoring of the traffic in farmed hides. But national crocodile industries are a possi- bility, and they could result in thriving natural populations that are free from the danger of extinction. Such prospects may also provide economic incentives for preserving the often-fragile ecosystem in which wild crocodilians live. Crocodile farming could play a part by slowing the uncontrolled draining of swamps and other wetlands that cover large areas of the lowland humid tropics of Asia, Africa, and Latin America. Crocodiles as a managed resource could economically benefit remote areas of the lowland tropics. Villagers there often have few alternative sources of income and possibilities for economic development are limited. Because the human population is relatively sparse, few opportu- nities exist for local trading; even where fish are abundant the problems of marketing are formidable. Indeed, in some areas crocodiles may con- stitute the only readily saleable resource. Crocodiles as Farm Animals Well-fed crocodiles grow quickly. Under ideal conditions they may reach lengths of 1 m or more in a year and 1.5 m in 2 years. They are nor- mally harvested in the third year when they reach about 2 m in length. In this time their value may have risen from about $5 to as much as $200. Crocodiles have acquired a reputation as voracious feeders; investiga- tions reveal this to be false. The animals actually have modest food re-
4 CROCODILES AS A RESOURCE FOR THE TROPICS quirements. Many hatchling animals have a food conversion rate of about 50 percent; that is, the crocodile adds 1 kg of weight for every 2 kg of food it consumes. Cattle, sheep, and pigs would have to eat 3-5 times as much food to achieve the same weight increase. After 2 years the croc- odile's growth rate begins to slow down. During the third year the con- version falls to about 25 or 30 percent, which is still a high figure, and makes crocodiles probably the most nutritionally efficient land animal for commercial husbandry. Only the growth of some fish is comparable. The high food conversion efficiency is due to the fact that crocodiles have low metabolic rates and are normally extremely lethargic. They are active only in short bursts, spend hours immobile, and move only about one-third as much as mammals. Moreover, being reptiles, they spend almost no food energy maintaining body temperature. They bask in the sun to keep warm and seek shade or water to cool off. For these reasons crocodilians can thrive in marginal habitats unsuitable for mammals or birds.* Crocodile farming is also space efficient. As long as they are sorted by size, hundreds of juveniles or dozens of larger animals can be penned together in a small area. Indeed crocodiles often choose to pile up on top of one another in stacks. Little is known about disease in reptiles. However, as farm animals, crocodiles have a major advantage: they produce antibodies readily and have few problems with external infections. In the wild it is common to find crocodiles missing limbs or tips of tails, with eyes gouged out, or enormous scars on the body. But the wounds heal readily, with little sign of infection.! This minimizes the need for veterinary services, a distinct benefit in remote village farms. Nevertheless, internal bacterial diseases, such as salmonella, can get out of hand and destroy a program by reduc- ing growth rates, lowering hide quality, or killing the animals outright. Crocodile Hides It is the belly skin that is the valuable part of a crocodile, and the worth of a hide is determined by the size of the belly skin, the smallness of its scales, and the hide's general condition. (Holes, cuts, scars, and rot drastically reduce its value.) Although international markets utilize any crocodile skin from 0.3 m to 6 m long, the most sought-after hides are not the biggest but the *Investigations on the Nile crocodile showed that a pelican takes 3 days to consume food equal to its own weight, whereas a crocodile takes 125-160 days (Cott, 1961). tThe American alligator is being used at the University of Florida College of Veterinary Medicine as a model for studies on antibody formation.
INTRODUCTION 5 moderate-sized ones from animals about 1.5-2 m long. These hides are approximately 25-50 cm in belly width.* Large hides, for example those more than 3 or 4 m in length, are suitable only for luggage and briefcases because their scales are large. Smaller hides, on the other hand, are suit- able both for items such as shoes, handbags, and wallets and for larger items. Internationally, the most desirable hides come from the saltwater croc- odile (Crocodylus porosus). It has proportionally the smallest belly scales of any crocodile, it lacks osteoderms.t and on the side of its body the scales are uniformly small. The next most valuable hides probably come from Morelet's crocodile (Crocodylus moreletii), the American alligator, the Siamese crocodile (Crocodylus siamensis), and the Nile crocodile (Crocodylus niloticus). Papua New Guinea The rest of this report highlights the program in Papua New Guinea, where during the last 10 years the government has made crocodile rearing an organized industry, much as poultry farming is elsewhere. This pro- gram, which is beginning to establish crocodiles as a significant natural asset, is designed both to protect the wild populations and to integrate traditional uses of these reptiles into a scientifically managed hide in- dustry. In Papua New Guinea crocodile farming}: has become the cornerstone for the economic improvement of some of the world's poorest people. It offers a means for bringing the rural poor into the process of economic development, and it can be blended into a traditional village structure where land and resources may be communally owned. The projects are small and many have had operational difficulties, but they suggest that conservation and economic development can be not only compatible, but also mutually reinforcing. The innovative idea is not that crocodiles can bring in money, but that sound conservation can be blended with marketing crocodile skins, meat, and by-products. An important aspect of this approach to crocodile conservation is that it is based on protecting the existing landscape and resources. It pro- vides a tool for conserving the species in their own wild habitats so that * A crocodile's total length is approximately 4-4.5 times the width of its belly. tOsteoderms are deposits of calcium carbonate under the skin. They are undesirable because they dissolve away during the tanning process, leaving a pitted surface, tin the official terminology of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the Papua New Guinea program is "ranching" rather than "farming" because the young livestock are mostly culled from wild populations and are not bred on the farm.
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8 CROCODILES AS A RESOURCE FOR THE TROPICS survival will not depend on a few captive specimens living under artificial conditions. It requires none of the bush clearing, fencing, forage plant- ing or pesticide spraying that domestic animals often demandâimpor- tant advantages in an economic development project in a fragile tropical swamp or rain forest ecosystem. The Papua New Guinea approach, then, provides an economic incen- tive for wildlife protection. Everyoneâfrom the villager to the minister of tradeâhas a stake in keeping the wild populations healthy. Out of self-interest, in addition to natural respect, large numbers of people become the guardians of the resource and the habitat needed to keep it surviving and productive. The world's major conservation organizations have given Papua New Guinea's crocodile program their stamp of approval. In 1976 a team of scientists representing the International Union for the Conservation of Nature and Natural Resources, one of the most prestigious conservation organizations in the world, inspected the program. As a result, Papua New Guinea was given special dispensation, and its crocodile skins can be legally traded internationally. For example, because of its endangered status the saltwater crocodile is banned from trade by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). An exemption, however, is granted to Papua New Guinea in rec- ognition of the fact that its crocodiles now are sufficiently well managed to sustain a skin industry without seriously damaging the wild stock. This program serves as a model for nations of the Americas, Asia, and Africa where crocodilian resources are still unmanaged or managed poorly. Crocodiles are being destroyed so fast that within about five years Papua New Guinea and other countries that have organized croco- dile farming operations may be the only ones supplying significant num- bers of skins to the international market. Although the principles developed in Papua New Guinea deserve inter- national attention, the recipe will not be a cure-all for problems of rural development or crocodile conservation. Instead, the Papua New Guinea experience suggests that local social, political, economic, and conserva- tion goals can become the impetus for a successful blend of village im- provement and wildlife protection. Previous pages. Feeding time at the Lake Murray demonstration crocodile farm. (Steve Raymer, 1981 c National Geographic Society)
