Captive Breeding

Last week, the 2nd to last to last wild born Spix's Macaw died. The 40 year old parrot, named Presley, was thought to have inspired the film Rio- about a pet parrot who is discovered and taken to join a captive breeding programme. Spix's Macaws are thought to be extinct in the wild, and less than 100 remain in zoos around the world. Most of these birds are closely related, so Presley was important because he was genetically very different. Unfortunately, although it was attempted, he never bred successfully, so his death is a huge blow for the future of Spix's Macaws. Here is your Quickfire Science on captive breeding programmes with Ginny Smith and Dave Ansell.

o According to the International Union for Conservation of Nature's Red List, around 17,000 species are listed as threatened with extinction. This is largely due to habitat loss and hunting.

o Captive breeding programs within zoos aim to protect the most endangered species from going extinct. Some of these will, eventually, re-release animals into the wild.

o The first success story was in the 1960s, when a captive breeding program allowed the Arabian oryx to be re-released after being hunted to extinction.

o More recently, golden-lion tamarins have been re-released in Brazil after a successful breeding programme, and their numbers are slowly rebounding.

o For a population to be healthy, whether captive or in the wild, it is important it is genetically diverse.

o When animals mate, the offspring receive one set of genes from the mother and one from the father. Usually, if one gene in a pair is defective it doesn't affect the animal.

o If, however, the parents are closely related, it is more likely the offspring will receive two copies of the defective gene, which can lower its survival chances. This is known as inbreeding.

o As a population becomes less genetically diverse, it is also more likely that a single illness could wipe out the whole group.

o Each zoo only holds a few individuals of each species, so they have to work together to 

prevent inbreeding.

o Groups such as the European Association of Zoos and Aquaria (or EAZA) carefully manage captive populations to ensure they are as genetically diverse as possible.

o Their animals don't 'belong' to a zoo, but are on loan from the EAZA, meaning they can be moved around in the way that most benefits the population as a whole.

o This reduces the need to take animals from the wild and, hopefully, leads to healthy and diverse populations.