Amur tiger cubs are classified as endangered (Photo credit: Calgary Zoo)
The three Amur tiger cubs, Kira, Samkha and Vasili, swapped birthday cake for deer carcass on Saturday as they celebrated a milestone birthday.
Families across Calgary turned out to wish -- and sing -- the cubs a happy birthday.
These tigers represent about one per cent of the world population.
Amur tigers are classified as endangered, and according to the World Wildlife Foundation there are only about 400 left in the world.
In the 1940s, hunting had driven the species to near extinction, leaving no more than 40 individuals in the wild.
Russia was the first country to grant the tiger full protection.
A full grown Amur tiger can weigh as much as 660 pounds, and grow up to 10 feet long.