It is mid-October in the Rockies, which means it is almost time to break out winter gear. As you dig through your garage to swap summer sandals for winter boots, do not be surprised if you disturb the hiding place of an insect or two. Maybe that insect is a spider, maybe even a Black Widow. Yikes! You probably do not want to share your shoes with a venomous spider.
But what exactly is a venomous spider, and why are we so afraid of them?
Long ago, spiders evolved venom to hunt and defend themselves. This adaptation has allowed them to thrive across every continent except Antarctica since they appeared around 495 million years ago. Unlike poison, which must be ingested or absorbed, venom is injected, usually through a bite or sting to immobilize prey or deter predators. In humans, venom can cause pain, paralysis, heart failure, and other severe symptoms, which explains our fear. But just remember that to a tiny spider, venom is its only defence. While large animals like mountain lions and bears rely on size, speed and strength, spiders use venom to survive on this big scary planet.
Back to the Black Widow in your boot; it is the only venomous spider you should be cautious of in Eagle County. These spiders are glossy black, and females have a bright red hourglass marking on their underside. A bite from a female feels like a pinprick, and releases a neurotoxic venom that can cause severe muscle pains, nausea, trouble breathing, and fever. Male Black Widows are too small to break human skin, so they pose little threat. If you suspect a bite, seek medical care immediately. While rarely fatal, complications can occur especially in children, older adults, and anyone with a weakened immune system.
Black widows are known for their glossy black bodies and red hourglass marking found only on females.
A large misconception is that we have Brown Recluse spiders in Eagle County. It is pretty much impossible for them to survive here because of our cold climate. Lucky us! The only instances of Brown Recluses here are due to them being transported over from other states, accidentally. They are also commonly confused with Wolf Spiders, which also have long legs and brown coloring. But fear not, Wolf Spiders are not dangerous to humans.
In fact, they are helpful. These spiders are fast and athletic, and thus do not even need to spin webs to catch prey. If you’ve ever tried catching one, you know how quick they are. They range in color from gray to brown to black, and often have striped body markings. If provoked they can bite, but it is harmless to humans. Their lightning fast moves are the result of evolutionary adaptations favoring speed over venom.
So next time you see what you think is a Brown Recluse, take a closer look. If it's a Wolf Spider, you may want to keep it around to deal with your pesky house flies.
As winter approaches and spiders, just like us, seek shelter indoors, remember they mean you no harm. Only one local species poses a threat and even then, bites are rare. It is worth educating yourself on which spiders are actually dangerous, and which are just misunderstood, because it can help you stay calm, cautious, and maybe even appreciative of these ancient survivors!
Lea Luetjens is a Naturalist at Walking Mountains. Admittedly also afraid of getting bit by a venomous spider, but working hard every day to appreciate what they do for us and our natural world.
