Tiger cubs born at Calgary Zoo

The Calgary Zoo welcomed three tiger cubs to its family Friday.

Cubs to stay in den for 3 months before being unveiled to the public

The Calgary zoo welcomed three tiger cubs to its family Friday.

The Amur tiger cubs were born between 4:30 a.m. and 7 a.m. MT and each weighed about 750 grams each.

The sex of the cubs is not yet known and they will remain in the den with their mother for roughly three months before they will be ready to venture out into public view.

Three tiger cubs were born at the Calgary Zoo Friday. (Calgary Zoo)

"It is early stages yet, but we are cautiously optimistic as we monitor the care that the mother, Katja, is providing to the cubs," said Colleen Baird, area manager. "We have infrared cameras in the den and so we are able to monitor the cubs and Katja’s behaviour without disturbing either.

"Right now she is doing absolutely everything right. Despite high mortality rates common in tiger births, we hope that all three cubs survive."

The tigers are classified as endangered and at last count there were only about 350 Amur tigers worldwide.

"The area around the tiger barn has restricted access and activity to minimize any disturbance and reduce the possibility of disrupting the mother-cub bonding that is so important in these first days after birth,"  said Baird.

Katja's last two attempts at motherhood were unsuccessful.

Zoo doctor feels third attempt 'right decision'

"While some critics may ask why we allowed Katja to breed again after two previously unsuccessful attempts, we felt strongly after considerable discussion that this was the right decision," said Dr. Jake Veasey, the director of animal care, conservation and research at the zoo.

He said Katja did everything right the last time — cleaning and caring for her cub until she recognized it was sick, at which point she walked away as she has evolved to do.

"We intervened, but even our best efforts and around-the-clock veterinary care were not enough to save that cub," said Veasey. "Something she essentially recognized before we did."

The birth is a result of a breeding program the Calgary Zoo participates in. It was recommended by the Association of Zoos and Aquariums’ species survival program that eleven-year old Katja and ten-year old Baikal mate.

"We have responsibilities beyond our responsibilities to the tigers at the Calgary Zoo and that is to support efforts to conserve these amazing animals by captive breeding to safeguard them against a very real threat of extinction in the wild," said Veasey.

The zoo says overall 19 cubs have been born at the zoo with 15 of those surviving, not including this litter.

The Calgary Zoo currently has three adult tigers: Baikal, Katja and 16-year-old Kita. Along with three other siblings, Katja was born to Kita at the Calgary Zoo on April 20, 2000.

Baikal was born at the Philadelphia Zoo on May 31, 2001. After a period of time at New York’s Bronx Zoo, he came to Calgary in February 2010 for the breeding program.