Breeding and Release Programs

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Captive breeding encompasses the controlled mating and breeding of animals in wildlife research centers, zoos, and aquariums, also referred to as captive propagation. These programs’ primary focus is critically endangered animals and plants, but animal programs present greater challenges. Animal breeding programs include considerations of the reproductive cycles of a mating pair, compatibility between male and female, requirements
for birthing and nurturing newborn, and means of safeguarding the mother and youngster from undue stress.

Some captive breeding centers take animals from the wild to add to their program for these two reasons: to rescue an animal from a severely endangered population or a severely damaged habitat, and to increase the genetic diversity in the group that is already part of the breeding program. Examples of animal populations that have benefited from these programs are the California condor (see chapter 2), red wolf, golden lion tamarin, Arabian oryx, Mongolian wild horse, peregrine falcon, Guam kingfisher, and Hawaiian goose. Aquariums conduct their own captive breeding programs to replenish endangered marine populations. In recent years the Monterey Bay Aquarium has embarked on a plan to be the first to breed a white shark in captivity; in the meanwhile it has housed and released transmitter-tagged white sharks back into the ocean, which the aquarium scientists then monitor via satellite signals.

Release programs work with animals originally captured from the wild and animals born in captivity. Release programs give biologists tense moments; an animal released to the wild is the culmination of thousands of hours of work. Jane Ellen Stevens of the Monterey Aquarium project said in 2008 shortly after a juvenile shark’s release, “We’re keeping our
fingers crossed that he’ll make it past fishing nets and hooks to survive to adulthood.” The breeding centers increase their chance for a successful release—one in which the animal survives in the wild and joins a social group—with vigorous training before the release. Volunteers and biologists teach animals to avoid humans, dangers such as traffic and power
lines, and predators. If possible animals also receive training on proper behavior in social groups. This training responsibility often falls to a mentor animal that lives permanently at the breeding center.

Veterinarians check to assure all animals are healthy; sick or injured animals do not return to the wild until they have recovered. Biologists then take them to the release site. The gray wolves of Yellowstone National Park stayed in pens for two months to acclimate to their new surroundings before biologists released them. Acclimation periods help animals learn about the scents and sounds of the new habitat, daylight patterns, and weather. Each biologist’s wish is to watch a healthy animal trot, swim, or fly into the wild without a glance back.