Officials at Zoo Knoxville in Tennessee are currently investigating the mysterious death of more than 30 reptiles in its main herpetology building.

According to the report from NBC News, 33 reptiles died due to an unknown cause between the evening of March 21 and morning of March 22. The building originally housed 52 animals. The surviving animals were evacuated and treated by the zoo's animal clinic and veterinarians from the University of Tennessee's College of Veterinary Medicine.

"This is a devastating and catastrophic loss to our zoo. These animals were important ambassadors who helped so many people understand the role snakes and lizards play in the balance of nature," said Lisa New, president and CEO of Zoo Knoxville, in a statement as reported by USA Today. "It is especially difficult for our herpetologists who have dedicated their careers to caring for and advocating for these animals."

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Only the main building in the reptile area was affected. Among the reptiles that died, three belongs to critically endangered species. These three were the Louisiana pine snake, the Catalina Island rattlesnake and the Aruba Island rattlesnake. Other notable snakes that passed away during the mysterious event include a forest cobra and an albino Eastern diamondback rattlesnake.

The affected building is temporarily closed due to the investigation. Zoo officials noted that tests were already conducted in the building. These tests include checking for harmful gases and for mechanical errors in the thermostat. Officials are still waiting for the official necropsy result to finally determine what caused the deaths of the animals. However, the cause of deaths, whatever it is, did not just target snakes. It just so happens that the affected building holds the majority of the snake population.

In addition to the dead animals, zoo officials also announced that several of their endangered or threatened breeding programs were greatly affected by the mysterious deaths.

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