Tarantulas Are On The Move In Southern Colorado

Something creepy takes place in southern Colorado this time of year. Tarantulas appear en masse scurrying across highways and up walls.

Arachnologists Paula Cushing, of the Denver Museum of Nature and Science, and Brent Hendrixson of Millsaps College in Mississippi told Colorado Matters that these big hairy spiders are simply out looking for love.

It’s easiest to spot them around dusk in late September into October. There’s two types of tarantula here in Colorado. Large brown tarantulas with leg spans of about five inches are found in the southeast part of the state. In the southwest corner of the state the tarantulas are smaller and black with leg spans of about three inches.

In either case it’s the males that are out and about. The females stay close to their spider silk lined burrows. Tarantulas spin silk, but not for webs.

The two scientists say that most tarantulas, including those found in Colorado, are not aggressive and are disinterested in biting people. They have to feel quite threatened before they will bite.

Hendrixson says,  “no one has ever died from a tarantula bite.”

Cushing adds that if you did get bitten it’ll hurt temporarily, like a bee sting and there are a few species in Australia that are the exception to this, which can be aggressive with a more toxic venom.

While tarantulas can make good pets, Cushing says it’s critical to make sure to only purchase lab raised tarantulas, as there are some species that are endangered because too many have been wild caught for the pet trade.

Cushing has led the Colorado Spider Survey since 1998, working with volunteers  and other scientists to collect tens of thousands of specimens. They’ve added their findings to a huge online database of arthropods, a bug database.

Hendrixson will speak about the biology, natural history, and diversity of U.S. tarantulas tomorrow, Friday September 28 at 11 a.m in Ricketson Auditorium at the Denver Museum of Nature and Science. The lecture is free with general admission to DMNS or DMNS membership.