San Diego Zoo Continues Successful Breeding Program For Endangered Pacific Pocket Mouse
April 16, 2014

San Diego Zoo Continues Successful Breeding Program For Endangered Pacific Pocket Mouse

Lawrence LeBlond for - Your Universe Online

After five longs years of planning, San Diego Zoo Global (SDZG) researchers were able to capture endangered Pacific pocket mice in 2012 and begin a breeding program to help bring the endangered critters back from the edge of extinction.

Following the zoo’s first successful breeding season that lasted from May to August 2013, of which 16 pups were born, researchers celebrated another round of successful mating, with the first litter of the second season arriving on April 1, 2014. The mother of the four hairless pups was herself the first mouse to be born in the captive breeding program’s 2013 season.

The program, which is managed by staff at the San Diego Zoo Institute for Conservation Research in cooperation with the US Fish and Wildlife Service, said after the four pups were born that another litter was expected by this past weekend. However, there has been no word of a second litter as of yet.

Debra Shier, PhD, Associate Director of Applied Animal Ecology, San Diego Zoo Institute for Conservation Research, said that the facility is hoping this year will be a more productive year for breeding as the 2013 season was started later than usual for the pocket mice. This year, the team has a full year of breeding and there is hope that an even larger number of pups are born.

Pocket mice remain active for breeding from spring to fall. The gestation period for a Pacific pocket mouse is 23 days and the species reaches sexual maturity in less than two weeks. With the season starting earlier this year, there is reason to believe that pups born in the first litter this year could be producing their own offspring in the fall.

The Pacific pocket mouse breeding facility uses air conditioning and humidifiers to mimic the coastal temperatures and humidity the mouse requires to thrive and breed. The facility is also equipped with large skylights to ensure these nocturnal rodents are attuned to the rising and setting sun, which cues their activities. Because of their nocturnal behaviors, the team must observe them at night without disturbing them. To do this, they rely on red light, which is not visually perceived by the mice.

Pacific Pocket mice, which were thought to be extinct in the 1980s, were rediscovered in 1993. Today, the mouse species is believed to only exist at three sites along Southern California’s coast: Dana Point, Santa Margarita and South San Mateo. The zoo staff expect to increase the overall population and maintain genetic diversity in this species through their breeding program. In the wild, the three habitats are divided by human development, so there is no chance for interbreeding between the populations.

Bringing species back from the brink of extinction is the number one priority of SDZG. As a leader in conservation, the work of SDZG includes onsite wildlife conservation efforts at the zoo, San Diego Zoo Safari Park, and San Diego Zoo Institute for Conservation Research, as well as international field programs on six continents.

The important conservation and science work of these entities is made possible by the San Diego Zoo Global Wildlife Conservancy and is supported in part by the Foundation of San Diego Zoo Global.