Calgary Zoo veterinarians are mourning the loss of a four-day-old tiger cub after it died overnight in the zoo's intensive care unit, according to officials.
Zoo officials say that after having worked through the night, the veterinary team believes the cub succumbed to complication from severe head trauma.
The surprise cub was born, along with another cub, to mom Katja on Tuesday - however the other cub was found dead by zoo staff. Veterinary staff weren't certain if Katja was pregnant to begin with, making the discovery of the two cubs puzzling.
Three veterinarians at the Calgary Zoo had been working in tandem to coordinate care for the struggling cub, providing round-the-clock care.
"What we've experience this week is the harsh reality of nature," said Dr. Sandie Black, Head of Veterinary Services at the Calgary Zoo.
"The fact that one in three cubs dies soon after birth, both in the wild and in captivity, is of little consolation right now."
The Calgary Zoo would like to thank staff, volunteers and the support of Calgarians during this challenging time.