A Critical Look at Captive Breeding Programs

mother and baby rhino

In most cases, captive breeding programs are a last resort to prevent endangered species from going extinct. (Photo credit: Phil Noble/Reuters/Corbis)

In 1973, the American peregrine falcon received the unfortunate distinction of being listed as an “endangered species” under the new Endangered Species Act. The falcon was one of the many species to fall victim to the pesticide DDT. While DDT was an effective combatant against insects that could potentially destroy crops, it also was poisonous to other wildlife and could work its way up the food chain to top predators such as the falcon through the process of biomagnification. When DDT was finally banned in 1972, it may have seemed as if it was too late to help the dwindling falcon population. The falcon, however, was able to survive thanks to the quick action of conservationists. In 1974, they began hatching falcon eggs in the lab and raising the chicks there for three weeks. The lab provided the falcon chicks with a realistic, yet safe, environment, as they were cared for by unseen benefactors. The chicks’ flight and hunting instincts were allowed to develop and, when the time was right, they were released into their natural habitat. By 1999, as many as 6,000 captive-bred falcons had been released.  The campaign was an apparent success, as in that year the peregrine falcon was officially removed from the endangered species list.

The breeding of wild animals in captivity is a practice with seemingly ancient roots. Rulers would interbreed their menageries, most likely to maintain desirable characteristics or perhaps to send the offspring as gifts to others. Captive bred animals also supply zoos, and, of course, perhaps the most common market for captive bred animals would be as pets. What is new to the modern age is the idea of captive breeding endangered species with the hopes of reintroducing the animals back into the wild in an attempt to help stave off extinction. While this might seem like a noble goal, and while it seems to have worked quite well with the falcon and some other species, the idea is not without its detractors. It isn’t that anyone disagrees with the sentiment, but only that the conditions under which captive breeding and subsequent reintroduction can be most successful are very complex. The falcons were lucky: the DDT that had poisoned them was banned from use when the birds born in captivity were set free in the wild. If it hadn’t been, or if there had been a new, unrecognized threat, they probably would have endured a similar fate.

For reasons such as this, the World Wildlife Fund (WWF) holds that captive breeding only should be used as a “last resort.”  They recognize that no amount of “new blood” introduced into an ecosystem to save a threatened species can fix the problems that are destroying the ecosystem in the first place or remove the threats facing the species. In one of the most expensive reintroduction programs ever, when captive-bred California condors were introduced to the wild, conservationists knew they had to be taught to avoid not only predators but power lines. What the conservationists didn’t realize was that the digestive juices in the condors’ stomach could digest lead shot. Even if the condor was protected from hunters, nothing could stop the birds themselves from eating the shot pellets found in carcasses and being stricken with lead poisoning. Steps needed to be taken to restrict all hunting in areas with condors.

Not only this, but the captive-bred animals might prove to be a threat to the ecosystem itself. The new animals could bring bad genes into the mix that might weaken the population. Their gene pool also could be too limited and thus lead to inevitable inbreeding. If the introduced members are too young, their inexperience could result in the population as a whole being less able to defend itself. If the introduced members are too old, they may not be able to breed as prolifically and so won’t be able to contribute as well to the propagation of the species. Whatever the case, there are a lot of variables at play when interfering with the dynamics of an ecosystem and until a program for introduction has taken all of this into account, any steps should be taken with caution.

One recent study has attempted to take all such “what if’s” into consideration and, as a result, decided not to recommend the introduction of captive-bred species. Key Largo woodrats are important to the ecosystem for how they spread seeds, erect stick nests that create shelter for other species, and are a food resource for other species, such as snakes and hawks. Development on the island pushed the woodrat from its natural habitat and eventually led to its classification as endangered in 1984. In 2002, a captive breeding program was established to help replenish the depleted population. Recently, researchers from the University of Florida’s Institute of Food and Agricultural Science used computer models to try to simulate what woodrats do in the wild and how this behavior is affected by being in captivity. They found that woodrats just don’t breed as well in captivity. The researchers were unable to breed the number of animals they needed to in the lab and, once introduced to their native habitat, the animals might not reproduce as quickly as those born in the wild. As co-author of the study Robert McCreedy stated, “When we kept looking at the data, what we found was that you really couldn’t breed enough woodrats to make it a viable strategy for population recovery,”

This all appears reasonable. Ecosystems and the relationships within those ecosystems must be carefully considered in order to minimize the risks when introducing new members of a species. The WWF, however, recognizes another, more “political,” drawback to captive breeding independent of whether or not it’s being done to ward off extinction. When rare, exotic in-demand animals are bred in captivity, the demand for them becomes even greater. Greater demand increases the likelihood that animals remaining in the wild will fall prey to poachers, thus decreasing already-small population numbers. Captive breeding, therefore, can have the opposite effect of intensifying the threats to some species, rather than eliminating them.

This isn’t to say that the WWF holds that captive breeding has no legitimate uses. Sometimes, it could be the only viable solution for highly fragmented and disturbed habitats where no other measure seems possible. Also, captive breeding, if done for research under strictly controlled conditions, can offer invaluable scientific insights into animal behavior as a whole. The important thing to remember is that breeding animals in captivity should only be practiced with an eye toward not hurting the species as a whole. As we have seen, the consequences of captive breeding can be environmental or economic, can be readily apparent or quite surprising, and could threaten both the captive-bred species and those individuals remaining in the wild. For whatever reason it’s done, captive breeding should be seen as only a part of a more complex interrelationship between humans and animals and the planet as a whole.

More to Explore
Captive Breeding – WWF Policy Statement
Smithsonian Conservation Biology Institute – Captive Breeding
Captive Breeding No Help to Endangered Woodrat

 

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