That leaves the situation "extremely precarious" for the critically endangered species, she said.

CNN: Rare gorillas threatened by rebels

The cheetahs are part of the European Endangered Species Programme (EEP) at the zoo, which looks to increase the number of the critically endangered species.

BBC: North African cheetahs born at Whipsnade Zoo

Over the last seven years 33 black rhinos have been born in the foundation's parks and members of the critically endangered species have been returned to the wild.

BBC: Black rhino threat: Poachers target Kent wildlife parks

Native to Africa, the black rhinoceros is classified as a critically endangered species, according to the Convention on International Trade in Endangered Species of Wild Fauna and Flora.

BBC: Three charged in rhino horn smuggling ring

Sumatran tigers are also a critically endangered species.

BBC: Aye of the tiger as pair go north

For instance, the San Diego Zoo received two female Chinese alligators from a zoological park in Florida in early July and wants to start breeding the critically endangered species if they can get a male Chinese alligator next year.

BBC: The dual sides of animal captivity

But with the help of some high-tech tracking devices, a fan-friendly Web site and a little star power, conservation officials are hoping a contest among 11 leatherback tortoises will raise awareness, and some money, for the critically endangered species.

CNN: Endangered turtles race to save their future

The species has been listed as critically endangered on the International Union for the Conservation of Nature's Red List of Threatened Species since 1996.

BBC: Earth News - Giant fish 'verges on extinction'

All five species are listed as endangered or critically endangered by the World Conservation Union.

FORBES: 12 Days of Charitable Giving 2012: Karen Beasley Sea Turtle Rescue and Rehabilitation Center

The species is one of the most critically endangered molluscs in the world.

BBC: Freshwater pearl mussels

Earlier this year the baiji or Yangtse River Dolphin was declared probably extinct, and the Critically Endangered vaquita (Phocoena sinus) - another species restricted to a small, specific habitat - will follow suit without swift action, conservationists believe.

BBC: Finance woes put porpoise at risk

The macaques are critically endangered, according to the IUCN Red List of Threatened Species.

BBC: Devon charity to track endangered macaque

The species, Eulemur cinereiceps, is listed as critically endangered on the International Union for Conservation of Nature (IUCN) Red List.

BBC: Linton Zoo celebrates rare white-collared lemur birth

The whale is listed as "critically endangered" by Russia and is on the International Union for the Conservation of Nature's Red List of Threatened Species.

BBC: Gray whales granted rare reprieve