Bison born at Toronto Zoo using frozen sperm from 1980

A wood bison calf was born at the Toronto Zoo from sperm collected in 1980.

That’s right, 35-year-old sperm was acquired from Elk Island, Alberta, by the Toronto Zoo and was successfully used during an artificial insemination to birth the wood bison calf late last month.

The Toronto Zoo is boasting that this is the longest-stored sperm used to produce a successful artificial insemination birth for a zoo species.

“This is an excellent example of genetic material used over ‘time and space,’” said Dr. Gabriela Mastromonaco in a press release.

Not only was one calf born from artificial insemination at the Zoo, but two. The baby calves were born on July 21 and July 28.

The two baby calves have yet to be named, said spokesperson Lesley Dean.

“We are getting over the excitement of the birth!” Dean said, adding that they will keep everyone posted once they have been named.

The mother is one of six artificially-inseminated wood bison at the Toronto Zoo.

The Toronto Zoo is home to one of only a few reproductive labs in North America that uses bio banking of wildlife.

Freezing living cells, such as sperm and embryos, is for the purpose of preserving genetic diversity for the future, according to the zoo.

And this isn’t the first time Toronto Zoo has given birth to artificially-inseminated wood bison calves, but the fifth consecutive year as part of an ongoing research program.

“We have been slowly improving the technique using only cooled sperm in the first two years, followed by frozen-thawed sperm for two years,” Mastromonaco said.

“Once we were able to get calves from frozen-thawed sperm, we felt confident in attempting an insemination with 35-year frozen sperm.”

The wood bison are currently “species at risk” due to heavy hunting and severe winters.

The Toronto Zoo said they have been involved in conservation of the wood bison since 1977 and have been working on captive breeding and the reintroduction of animals back into the wild.