Breeding is going strong at our Pacific Pocket Mouse Conservation Breeding Facility at the San Diego Zoo Safari Park. We currently have three pregnant females. Our second pairing (described in Pocket Mouse Matchmaking) between lovely lady #22 (of South San Mateo) and handsome gentlemen #21 (of Santa Margarita), after the birth of our first pup, on June 11, has lead to another successful birth!
The female started building her nest just like the previous female did, in preparation for the new arrivals. Interestingly, females in this species don’t start to show physical signs of pregnancy until a week before giving birth. Female #22 began gaining weight slowly from 0.3 to 0.4 ounces (7.7 to 12 grams), over one week.
Four pups were born into a humid nest on July 4. Their mother was actively lying on top of her pups and significantly thinner.
Each of her pups is about 1 inch (2.54 centimeters) long and crawling on top of each its siblings to stay warm. Over the next three weeks, these pups will be protected and cared for by their mother until they are foraging for themselves.
Amaranta Kozuch is a senior research technician at the San Diego Zoo Institute for Conservation Research.