In an event that happened sometime between March 21 and March 22, Zoo Knoxville lost 33 reptiles.

The incident occurred between the hours of 5 p.m. on Tuesday and 8 a.m. on Wednesday and what exactly happened is still under investigation.

When zoo staff entered the building on Wednesday morning, they found 30 snakes and one lizard unresponsive. The zoo’s animal clinic and vets from the University College of Veterinary Medicine responded immediately.

Surviving animals were evacuated and given oxygen. Each unresponsive animal was checked for a heartbeat with ultrasound equipment. 33 of the 52 animals in the building died.

Popular snakes, like a forest cobra and albino Eastern diamondback rattlesnake, and three critically endangered species, the Louisiana pine snake, Catalina Island rattlesnake and Aruba Island rattlesnake, were among the fatalities.

“This is a devastating and catastrophic loss to our zoo,” said Lisa New, President and CEO of Zoo Knoxville. “These animals were important ambassadors who helped so many people understand the role snakes and lizards play in the balance of nature. We also lost breeding programs for several endangered and threatened species. It is especially difficult for our herpetologists who have dedicated their careers to caring for and advocating for these animals.”

The building where the event occurred has been taken out of use while the event is investigated and necropsy results are performed. The other buildings in the zoo’s reptile facility were not impacted and continue to be used for housing and public viewing.