1 Introduction

Crocodiles, alligators, caimans, and gavials ( Present-day crocodilians are grouped into three families: crocodiles, alligators and caimans, and gavials (gharials). The animals differ from one another only in minor characters 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.) have existed for some 200 million years - much longer than mammals - but they are now disappearing at alarming rates. Of the 21 or so species of crocodilians distributed in the warm waters of the world, at least 18 are threatened with extinction 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-spouted 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 denuded. 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 expensive luxury articles has far exceeded supply. Even small items such as purses and handbags sell for many hundreds of dollars each. For instance, a ladies' purse or handbag made from crocodile skin can command 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 absorbed 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 number 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 populations, 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 mississippiensis). Ten years ago its future seemed doubtful, but the legal protection of the populations has brought a remarkable recovery. Numbers are now so high that two states have lifted the ban on harvesting alligators, and between lo,ooo and 20,000 American alligator hides now enter commerce each year.

The past few decades have seen several other examples of successful crocodile-rearing projects. Later chapters of this book highlight the national 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 animals 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. Appendix 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 experiences 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 possibility, 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 opportunities exist for local trading; even where fish are abundant the problems of marketing are formidable. Indeed, in some areas crocodiles may constitute the only readily salvable 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 normally 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; investigations reveal this to be false. The animals actually have modest food requirements. 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 crocodile's growth rate begins to slow down. During the third year the conversion 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 (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.)

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 (The American alligator is being used at the University of Florida College of Veterinary Medicine as a model for studies on antibody formation.). 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 reducing 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 moderate-sized ones from animals about 1.5-2 m long. These hides are approximately 25-50 cm in belly width.( A crocodile's total length is approximately 4-4.5 times the width of its belly). 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 suitable both for items such as shoes, handbags, and wallets and for larger items.

Internationally, the most desirable hides come from the saltwater crocodile (Crocodylus porosus). It has proportionally the smallest belly scales of any crocodile, it lacks osteoderms,(Osteoderms are deposits of calcium carbonate under the skin. They are undesirable because they dissolve away during the tanning process, leaving a pitted surface),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 program, 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 industry.

In Papua New Guinea crocodile farming (In 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) 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 provides a tool for conserving the species in their own wild habitats so that survival will not depend on a few captive specimens living under artificial conditions. It requires none of the bush clearing, fencing, forage planting or pesticide spraying that domestic animals often demand ,important advantages in an economic development project in a fragile tropical swamp or rain forest ecosystem.

The Papua New Guinea approach, then, provides an economic incentive for wildlife protection. Everyone ,from the villager to the minister of trade ,has 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 recognition 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 crocodile farming operations may be the only ones supplying significant numbers of skins to the international market.

Although the principles developed in Papua New Guinea deserve international 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 conservation goals can become the impetus for a successful blend of village improvement and wildlife protection.