The population of black-tailed prairie dogs at the San Francisco Zoo just grew by nearly 50 percent, as one prairie dog mom just birthed nine pups, who have just emerged into the daylight.

Prairie dogs, which one conservation biologist referred to as the "chicken McNuggets of the grasslands" because they are prey to over 100 other species, are also very cute relatives of the common squirrel with a highly developed language. Prairie dogs construct elaborate underground burrows, ultimately forming "towns" consisting of dozens of families called coteries. As the SF Zoo tells us, "the biggest prairie dog town on record was about 100 miles wide and 250 miles long, and home to an estimated 400 million prairie dogs."

Black-tailed prairie dogs, like those they have at the SF Zoo, live alongside the meerkats in the zoo's Prairie Dog and Meerkat exhibit, but in the wild they are found in the Great Plains and across grasslands in the western U.S. and Canada.

Female prairie dogs go into estrus only once a year, in late winter, for about an hour, and if they mate successfully they'll gestate for just over a month.

The latest litter of nine pups joins around 20 prairie dogs who were already in the exhibit, and the zoo says they are now about five weeks old, as they have likely been safe in their nest since birth sometime in March.

While not endangered in the wild, prairie dogs' habitat around the world is estimated to have decreased by 95%.

SF residents and guests are encouraged to come to the zoo and try to count all the prairie dogs themselves.

Previously: Rare Baby Rhino Born at Sonoma County's Safari West