BALBOA PARK — Today, Christmas Day, the San Diego Zoo keepers will wean a baby reindeer from his bottle. The reindeer, Boris, was born Sept. 18 at the zoo. His mother arrived at the zoo in May and was unexpectedly pregnant, according to a zoo statement. “It has been so much fun watching Boris grown up here at the San Diego Zoo,” said Tammy Batson, lead keeper at the San Diego Zoo. When Boris was born, he weighed eight pounds. Now, he is just over three months old and weighs roughly 75 pounds, zoo officials said. His diet consists of grasses, acacia, hay and alfalfa-based pellets. Reindeer typically live 15 to 20 years, zoo officials said. Boris can be viewed in the confines of the zoo’s Polar Rim region. The San Diego Zoo is open year-round. For more information, visit www.sandiegozoo.org. — Debbie Hatch