As part of my PhD thesis at Colorado State University in Fort Collins, I study the Texas brown tarantula (Aphonopelma hentzi) in the short-grass prairie. My colleagues and I work on the Southern Plains Land Trust, a piece of private conservation land about an hour south of Lamar, Colorado. These tarantulas’ habitats range from Louisiana to this southern part of Colorado. The prairie is a harsh environment — super dry, windy and sometimes very hot or cold. The tarantulas’ burrows become their lifeline; they stay in there for the long haul. Only the males, once mature, leave their burrows to wander aimlessly, looking for love.
Tarantulas are ambush predators, meaning that they wait for food to walk by. We want to know if they build burrows in a consistent way, and how their burrows help them to survive the prairie’s harsh environment.
We lure the tarantulas out of their burrow using a piece of grass, and then we collect them with a one-litre plastic cup. We pour quick-set plaster of Paris into the burrow. Once it’s dry, we dig out the cast. The first one, that I’m holding here, turned out to be 60 centimetres deep. This does destroy the burrow, but we dig the tarantula a new starter burrow nearby.
The casts show us that some spiders are very clean and keep their burrows empty, whereas others are trashy, keeping previous moults or leftovers from eaten beetle. One of the burrows looked as if it had been borrowed from a much bigger animal. That is high-end lazy.
About 90% of US prairies are gone because of agriculture and ranching. We strive to preserve the prairie and the creatures in it. Tarantulas serve as a force for keeping insect and even rodent populations under control in the prairie ecosystem. Tarantulas are big, but they won’t hurt you. Want fewer insects? Let spiders live in your house. They’re in your bathtub only because they are thirsty.