San Francisco’s bison herd in Golden Gate Park dwindled to three cows this summer after two of the aging five-member all-female herd were euthanized.

Soon their numbers will grow to 10, thanks to seven bison calves that are currently under quarantine near the park’s main bison paddock, the San Francisco Recreation and Park Department announced Tuesday.

The presence of bison in captivity in Golden Gate Park dates back to the 1890s, when a small herd was purchased by the park commission.

The most recent herd of five cows were descendants of bison given in 1984 to then-San Francisco Mayor Dianne Feinstein by her husband, Richard Blum.

But in July, 28-year-old Pretty Old Cow and 20-year-old Tenny were put down after both displayed signs of sickness and old age, according to San Francisco Zoo spokeswoman Lora LaMarca.

The average lifespan of a bison is about 20 years, although bison in captivity tend to live longer than bison in the wild, according to zoo officials. The zoo, in partnership with the parks department, manages the bison’s health and welfare.

The parks department coordinated with Assemblywoman Fiona Ma, D-San Francisco, the zoo and Blum to rejuvenate the herd and renovate the paddock.

According to the parks department, the search for replacement bison began a few years ago, and Ma put the department in touch with a bison rancher in Corning, Calif., which is outside of Redding.

The young bison will be introduced to the paddock in early 2012 with an official welcome ceremony hosted by the parks department.

Zoo Assistant Curator Jim Nappi said the young bison have been taking very well to their new environment despite the constant flow of traffic and visitors to the area and the presence of dogs at a dogpark adjacent to the paddock.

“They’re very calm,” he said. “They’re together as a group, the herd dynamic is very strong.”

The young calves were chosen, Nappi said, because they are more likely to adapt to the established herd dynamics of the elder cows.

“We didn’t want new bison coming in as adults…and henpecking the adults who’ve lived there their whole lives,” he said. “Because they’re young calves, they’re still forming who they are, they’re still learning what it’s like to be bison.”

Until the calves are formally introduced to the herd at the end of their quarantine–which Nappi tentatively said could be around the end of February–the general public is encouraged to dream up names for one of the calves as part of a naming contest. The winning name will be announced at the official welcome ceremony, according to the parks departments.

Names can be submitted online–through a parks department website, Facebook, Twitter or email–through Jan. 13, 2012. More information on the contest is available at

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