Births were the first at Polar Frontier
Powell, OH – Polar bear cubs were born Saturday, Dec. 20 at the Columbus Zoo and Aquarium but they did not survive.
Animal care staff observed the births while monitoring the mother’s activity from a camera mounted in the den. The first birth, recorded at 5 a.m., appeared to be stillborn. The second cub was born about two hours later and the mother, Aurora, appeared to begin caring for it.
The Zoo team could hear the cub vocalizing and observed Aurora, an inexperienced mother, holding the cub in a proper nursing position. Despite Aurora’s apparent care for the cub, the cub’s vocalizations stopped by the afternoon and the animal care team was unable to see it.
The Columbus Zoo animal team, in conjunction with recommendations from other polar bear breeding facilities, made the decision not to intervene. Polar bear cubs are difficult to hand rear and disrupting Aurora’s maternal care was not advised.
Polar bears have one of the lowest reproductive rates of any mammal. The survival rate for a polar bear cub during the first few weeks of life is only about 50 percent.
“While we would certainly wish for a better outcome the birth of these cubs is a major step in our polar bear breeding program,” said Curator Carrie Pratt. “We will likely never know why the cubs did not survive but we do know Aurora is able to reproduce and she has gained experience. She’s still a young bear and has many reproductive years ahead of her.”
Female polar bear twins Aurora and Anana arrived at the Columbus Zoo in 2010 when the Polar Frontier region opened. The twins are now seven years old and both have mated with the 27-year-old male polar bear, Nanuq, who arrived in 2012. All three polar bears came from other zoos on breeding loans as part of the Species Survival Plan for the threatened species.
It is unknown if Anana is pregnant, however her desire to den and elevated progesterone levels indicate it is a good possibility.
Female polar bears generally have their first set of cubs between the ages of four and eight years. Due to delayed implantation, the gestation period can range from about 195 to 265 days. Pregnant polar bears den in the fall and give birth, generally to two cubs, in the winter. The cubs typically weigh about one pound at birth, growing quickly on their mother’s fat-rich milk before emerging from the den in the spring.
Polar bears are native to the circumpolar north including the United States (Alaska), Canada, Russia, Norway and Denmark (Greenland). They are at the top of the Arctic food chain and primarily eat seals. Polar bear populations are declining due to the disappearance of sea ice, and experts estimate that only 20,000-25,000 polar bears are left in the wild. Some scientists believe if the warming trend continues two-thirds of the polar bear population could disappear by the year 2050.
“Polar bears need our help,” said Columbus Zoo and Aquarium President and CEO Tom Stalf. “We are committed to doing everything we can at the Zoo, as well as supporting conservation initiatives for wild populations, to save these magnificent sea bears.”
The Columbus Zoo and Aquarium has been designated an Arctic Ambassador Center by Polar Bears International.