Earth Notes
9:02 am
Wed August 21, 2013

Earth Notes: Living Fossils On The Colorado Plateau

The southwestern United States are ground zero for scorpions. Of the 90 species that are native to the United states, most inhabit the desert southwest. At least 16 live on the Colorado Plateau Alone.

Scorpion under black light
Scorpion under black light
Credit National Park Service

They have a fearsome reputation. But the sting of most species is mild, like that of a bee. The sting of the Arizona Bark Scorpion, the most venomous of these arthropods in North America, is very painful, but even it rarely causes death.

Scorpions are well adapted to life in the Southwest. They are active at night, when predators are fewer and temperatures are cooler. Most of our local species are tan in color, blending with the landscape. And their slow metabolism, combined with a fairly inactive lifestyle, allows them to survive 6 to 12 months without food.

While scorpions have been spotted as high as 9,000 feet in elevation on the Colorado Plateau, the lower in elevation you go, the more likely you are to encounter them. If you're eager to see one, bring a black light on your nighttime search - a scorpion's exoskeleton glows under ultraviolet light, possibly a means of attracting nighttime prey.

Above all, scorpions are survivors. They have changed little in the 300 million years since they became some of Earth's first land-dwelling invertebrates. What's more, they have specific habitat needs and move around very little. As a result, scientists studying them have learned a great deal about how geological changes have affected where different types of animals live.