Rat snake study the longest of its kind at Dallas Zoo


For more than 20 years, the Dallas Zoo has studied an animal that doesn’t even have a permanent home inside Texas’ largest zoo.

The Texas rat snake (P.obsoleta) slithers (and climbs!) onto the Dallas Zoo grounds every spring in search of food. These snakes, while not venomous or harmful, may alarm Zoo guests because of their large size.

Since 1989, Zoo herpetology staffers have captured, marked, examined, and released the snakes away from Zoo animals and guests. It’s the longest study of urban snakes of any kind.

Wait, releasing the snakes?!?

“They’re completely harmless, big snakes that eat a lot of rats,” Herpetology Supervisor Bradley Lawrence said.

Given that a female rat can produce hundreds upon hundreds of babies, Texas rat snakes are like Dallas Zoo junior staff members, keeping the rat population maintained. Because the Zoo sits on more than 100 acres of heartland prairie forest, rats are simply part of the ecosystem.

The snakes are tracked with digital transponders, the size of a grain of rice, inserted just below the skin. This transponder identifies the individual snake with a unique number. When a snake is found, reptile keepers scan for the transponder and note weight, length, sex, and physical description. They also add notes of what they find: “Swallowed decoy egg … Regurgitated fledgling bird.”

Texas rat snakes that find themselves with injuries or other ailments (like swallowing a decoy egg, used to encourage nesting) get an extra-long stay at Château Dallas Zoo to see our veterinarians before being released back in the wild.

Since tracking began, 20 different snakes have been caught repeatedly over four-year periods, and two snakes have lived around the Zoo for more than seven years.

The data, which has more than 1,000 captures, is teaching Zoo herpetology staff about how these urban-environment reptiles live.

“We want to learn growth rates, what they prey on, their movement pattern, and how urban spaces affect their population,” Herpetology Curator Ruston Hartdegen said.

Don’t be alarmed if you see a Texas rat snake, at the Zoo or anywhere else in Dallas. If you’re visiting us, just alert Zoo staff and we’ll happily scoop the snake up to be examined, released and tracked.

Categories: Reptiles and Amphibians | Tags: , , , , , , | 3 Comments

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3 thoughts on “Rat snake study the longest of its kind at Dallas Zoo

  1. Wayne Carter

    I think my scream of terror would be enough to alert zoo staff if I happened across a huge snake *not* on the other side of a glass enclosure.

  2. Suzette Shelmire

    One of the fun and educational events that happened in the old children’s Zoo on the hill was a visit periodically from these interesting Texas Rat snakes. They loved to go for the eggs that our C.Z. ducks were setting. We would call the boys in the Reptile house and they would come running to check to see if it were a new snake or one of our habitual visitors, I do remember that they took them way off down to the creek or farther to let them go after studying them and some would find themselves BACK at the Children’s Zoo in what I thought was record time for an animal with no legs! Most of the Junior Zookeepers were fascinated!

  3. Susan Eckert

    I think this is really fascinating. We don’t know enough about the snakes in our neighborhoods. Keep us updated on future findings!

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