Cortez is home to hideously amazing creatures: the creepy crawlies of Southwest Colorado.
Each hair-raising in their own way, they play a vital role in pest control by eating everything from insects to rodents.
These four animals that crawl and slither among us, often in our own backyards, are evolutionary masterpieces.
Lactrodectus hesperus
The western black widow spider is mesmerizing. The female’s eerie glass-marble body sends shivers down spines. She is believed to be 15 times as poisonous as a rattlesnake – the red hourglass on her abdomen a symbol of danger. And they’re all over Durango.
“They won’t kill you, but if you do get bitten, you might wish you were dead,” said Paula Cushing, curator of invertebrate zoology at the Denver Museum of Nature & Science.
Get a closer look at night. About one-quarter to one-third of an inch in length, they hang upside down around clutter – wood piles, behind flower pots, around the gas meter. They hang motionless but are capable of startling movement. Their webs are a mess, seemingly unkempt disarrays of silk, but one strand has more tensile strength than steel.
Black widow bites aren’t fatal. In fact, Cushing said, they’re rare.
“They’re really timid, and not particularly aggressive,” she said. “My latest party trick is to handle black widows in front of an audience.”
But, if bitten, the venom takes effect in minutes.
“It has what’s called a neurotoxin,” Cushing said. “The pain includes a hardening of the stomach muscles, pain in the abdomen, pain in the joints, pain in the lymph nodes and facial contortions. Those are the classic symptoms and can last up to four days.”
Anti-venom is available, but its use is debated. It comes from antibodies in the blood of a horse that has been injected with the venom over time.
The name black widow comes from the unsettling circumstance that females devour their partners after sex, but many males actually coexist with the females after mating.
“As long as the female’s well-fed and the male plays his cards right, she might let him escape,” Cushing said. “But if she’s hungry, all bets are off.”
Every night, they’re waiting for their next victim: a grasshopper, a moth, another spider, sucking their liquidated guts out by way of enzymes injected with their hollow fangs – the creepiest drinking straws ever.
Solifugae
Unlike the black widow, Solifugae move incessantly on the hunt. This order of animals has many names: sun spider, camel spider, wind scorpion, but they are neither spider nor scorpion, it’s an order of arachnid all its own.
Often encountered dashing across shed floors or exploding out of gardening projects, it looks like some horrid cricket-spider mutant. In Colorado, they’re around an inch long at most, but come out like a heavyweight champion.
“They’re harmless, although they act like they’re going right for your jugular,” Cushing said. “And they’re incredibly fast.”
Solifugaes can travel with surprising speed for more than an hour without stopping.
“They’re a voracious predator,” Cushing said. “Mostly insects and other spiders – they grab them with their powerful jaws, clamping onto them and tearing them apart.”
Solifugae have four sets of legs and an added set of sensory appendages called pedipalps.
“They hold these pedipalps in front of them, covered in hair-like structures picking up vibrations, sensory cues,” she said. “They’re crazy fast, with an alarming charge.”
Aphonopelma
As Solifugae are speedy and grumpy, this giant genus of spider is slow and docile, despite their terrifying appearance.
Just the sight of an Aphonopelma is enough to make some people faint.
“They’re pretty innocuous,” Cushing said. “If you get bit, it will hurt, but it would feel more like a wasp sting. They’re nothing to worry about.”
Except they’re the stuff of nightmares.
“All the tarantula migrations that people see in the late summer and early fall are actually the adult males,” Cushing said. “They mature, leave their burrows and start cruising around looking for a good time.”
Females can live up to 20 and even 30 years. With big, hairy bodies and massive fangs, tarantulas eat anything from large insects to lizards they leap on from burrows. But it’s not their fangs that are their best defense.
“They might rear up to bite, but more likely they are going to brush those hairs in the face of whatever is attacking,” Cushing said. “That cloud of hair gets into those sensitive tissues, and it’s going to be really irritating.”
Cushing, called all spiders our pest control.
“They’re the good guys, not the bad guys,” she said. “They’re eating trillions of insects in every terrestrial habitat in which they’re found. They’re really important insect control mechanisms.”
Crotalus viridis
Unlike spiders, Crotalus viridis have no legs at all, but they still move with grace and speed.
Rattlesnakes actually are common around Durango. They’re fast, almost invisible and can dislocate their jaws to swallow their food. Often found near rocks and cliffs on sunny aspects, the cold-blooded creatures maintain their body heat from their environment.
In Southwest Colorado, we have two of the three venomous snake species in the state, the prairie and the much smaller midget-faded rattlesnake, said Tina Jackson, species conservation coordinator with Colorado Parks and Wildlife in Denver.
“You want to not be bit by one of them,” she said.
However, deaths from rattlers in Colorado are rare. But their venom is a hemotoxin, attacking red blood cells, destroying tissue and causing swelling and intense pain. Like spiders, the venom is a digestive aid.
Contrary to common belief, cutting or sucking around the bite is ineffective, according to Wilderness Medical Associates’ protocol. There may not even be any venom.
“They can actually give you a dry bite,” Jackson said. “From the rattler’s perspective, the venom is to help catch and digest food, and not to scare off big things like humans hiking at you.”
“One thing they can do is track their victim, so they know which (animal) they bit,” Jackson said. “Then they swallow the thing whole.”
She said a 3- or 4-foot prairie rattler with a head the size of a half dollar has no trouble swallowing a rabbit or prairie dog. But they can’t eat us. And like other animals, the rattlesnake’s most feared weapon is usually its last choice.
“They’re not very aggressive animals,” she said. “Most rattlers are very cryptic, so the first thing they’ll do is be very still.”
The rattle is made of keratin, similar to our fingernails. When a snake shakes this maraca of terror, it’s a universal for “I’m warning you.”
“It will protect itself remarkably fast, so you want to give it plenty of space,” Jackson said.
During the summer, they become more active at dawn or dusk, she said.
Our backyard beasts may be frightening, but they play a vital role. If it weren’t for these chilling creatures, we’d be up to our necks in other ones.
“They’re important creepy crawlies,” Jackson said.
