Brent Hendrixson, a professor at Mississippi’s Millsaps College, has always been fascinated with spiders. (Courtesy photo)

Every fall, Ailene Smith imagines this horrible scenario.

Some kid picks up a roaming male tarantula while he’s waiting for the school bus on a fine fall Nucla or Naturita morning. He stuffs it into a Crayola box, perhaps, or an empty disposable cup, and decides to take it to school, just for fun.

The bus comes along. The kid and the spider get on that bus. The spider somehow gets loose. It crawls down the length of the school bus aisle. It eases its hairy little legs up the pant leg of the driver. The driver feels a little tickle. Glances down. Freaks out. And, crash!

“It could happen,” Smith says. “I imagine wrecks like that. And it’s actually not just me. There are a lot of kindred spirits. You hear about bees getting in the car and causing accidents all the time. Why not a tarantula?”

All her life, Smith has dreaded the season of the wandering tarantulas in the West End. The hairy black arachnids that crawl haphazardly across the countryside around Nucla, Naturita, and Dove Creek and tap-dance their way through the shimmer of heat-miraged highway, stumbling around with their eight beady close-set eyes and eight hairy legs, and venom glands, and fangs, hoping to encounter a female and get lucky.

A lifelong resident of Nucla, Smith never actually saw very many West End tarantulas until she started working as a custodian at the elementary school down in Naturita.

“They come right down off the mountain and right into the building,” she said. Crawling across the gym floor. Easing their way out of the lockers where kids have stowed them as “pets.”

This year hasn’t been quite so bad. “But last year, there was a lot,” Smith said. “So many.” Between the kids picking them up and letting them crawl on their hands and jackets, and the kids chasing her down the hallway with them because they know she’s scared, and the kids who are stepping on them because they’re as scared as she is, tarantula season pretty much sucks for Smith.

“I wouldn’t step on them myself,” she adds. “I don’t want to clean it off my shoe. It would be ‘ick’ for sure. But I do run over a couple of tarantulas a year. As many as possible.”


For Smith, and the millions of other human beings that are afraid of spiders, the only good arachnid is a dead arachnid.

But plenty of other West Enders love them, and wouldn’t consider fall to be complete without at least one good tarantula sighting.

Brent Hendrixson loves them too. The Colorado native, who was born and raised in Thornton, has been fascinated by spiders since he was a little kid. Indeed, his very first memory is of his older brother collecting a jumping spider and a fly.

“He handed the jar to me and said, ‘Watch,’” Hendrixson recalled. “I still cannot describe in words the excitement and wonderment I felt as I watched this intelligent and daring little arachnid stalk its much more agile prey, calculating every move, before pouncing and enveloping the insect in its venomous grasp.”

Hendrixson was soon plucking spiders out of webs with his own bare hands. By the time he was six, he had his first pet tarantula.

Fast-forward a dozen years, and Hendrixson went off to study biology at the University of Northern Colorado. During his junior year, in the spring of 1998, he took a herpetology class and went on field trip to the southeastern part of Colorado, near La Junta.

“My biology professor told me there were tarantulas out there,” he recalls. “I had no idea. I did not believe him.”

But sure enough, he was able to collect his first wild tarantula from that area. “I was curious about what species it was, and started doing research,” Hendrixson said. He figured a lot would be known about them. But in fact, the opposite was true.

“The more research I did, the more I found out there was nothing known about these things,” he said.

Turns out, the study of spiders is not exactly a crowded field. For the young biology student with a fascination for all things eight-legged, it was an ‘Aha’ moment. He went on to live the dream, getting his doctorate in biology, and spending the past 25 years studying the diversity, evolution, and conservation of spiders.


Today, Hendrixson is a biology professor at Millsaps College, a small, private liberal arts college in Jackson, Mississippi. He is considered to be one of North America’s top tarantula experts.

Recently Hendrixson and his colleagues published a monograph that documents all the different tarantula species in the U.S., including two species in Colorado.

Grand Canyon black tarantulas (Aphonopelma marxi) live in the southwestern part of the state, including the West End, while Oklahoma brown tarantulas (Aphonopelma hentzi, also known as Texas brown tarantulas) reside in the southeastern plains, and can be frequently spotted in the Comanche National Grassland south of La Junta off U.S. Highway 109.

What is it about tarantulas that captures Hendrixson’s fancy? “There is something sort of charismatic about them,” he said. “They are big, and conspicuous, and they evoke feelings from just about everyone. There is no middle ground. They are really interesting animals. The more I studied them, the more I learned.”

Hendrixson is especially interested in the Grand Canyon black tarantula. It has one of the biggest distributions in the United States, ranging throughout the Four Corners region from the Grand Canyon to the high deserts of southwestern Colorado, and from southeastern Utah to northern New Mexico.

Considerably smaller and more dapper than its drab, brown southeastern Colorado cousin, Aphonopelma marxi are jet black, with red or orange hairs on their back end. “It’s a strange color pattern,” Hendrixson said. “They are lookers for sure.”


Right now, at this very moment, the males of both Colorado tarantula species are on the move, propelled by ancient instinct, pouring their hairy legs across the landscape in a graceful, almost liquid, eight-legged ballet.

“Sometimes it’s called a migration, but that is not what this is,” Hendrixson said. “Migration implies coordinated directional movement toward an area, and that the movement will come back where it came from. This is simply breeding season. The males emerging from their holes in the ground have just reached maturity. They are single-minded, looking for females, recklessly abandoning the retreats that have sheltered them throughout their lives.”

And they will never return to their homes again.

Around Nucla, Naturita and Dove Creek, Aphonopelma marxi can frequently been seen this time of year walking across highways, randomly wandering in search of females. The females, meanwhile, are trickier (and much more unusual) to spot because they live in holes in the ground, and don’t like to come out except when they are hunting at night. Or mating.

Grand Canyon black tarantulas are diurnal, which means that they mate during the day. That makes the wander-lusting males extra easy to see.

“The best time to find them is between 9 and 10 in the morning up until early afternoon, before it gets too warm,” Hendrixson said. “Drive down the road and if you see something black moving across the road, slow down and take a look. It is probably a tarantula.”

In Hendrixson’s experience, the most productive place to view Grand Canyon black tarantulas in southwestern Colorado is located along Highway 491, between Dove Creek and Cortez. They can also be spotted in October and early November along Highway 97 (aka the “Nucla Loop”), Highway 141 toward Slick Rock and Dove Creek, and Highway 90 toward Bedrock and Paradox, in the area of western San Miguel and western Montrose counties commonly known as the West End.

“It’s not as common to see them in towns, but I have seen them walking down the streets in Nucla,” Hendrixson said. 

Tarantulas are long-lived spiders, and experts believe that it takes the male Grand Canyon black tarantula eight to 10 years to reach sexual maturity. They will stay in their burrows until that time, molting once a year or so in order to continue growing. As long as the males are in their burrows, their legs are shorter and thicker, like females’.

But when they go through their last molt before reaching sexual maturity, their bodies undergo drastic changes, and their legs become much thinner and more elongated.

“They are getting ready to walk, and they have to have the ability to walk really well,” Hendrixson said. A typical male Aphonopelma marxi will wander about half-a-mile every day looking for a mate — “like us walking a marathon,” he said. “It’s a significant distance.” And just like for humans, “Long slender legs allow them to do that.”

Mature male tarantulas also have spurs or spines on their second set of legs, used for securing a female mating partner to assure she can be positioned correctly.


Wondering how tarantulas do it? First, it’s important to understand a few more things about their anatomy.

If you look at a picture of a female tarantula, you will see that she has eight legs like any other spider. She also has a couple other appendages, like smaller legs, right near the front of her body. These are called pedipalps. Males have them, too.

“They look like small walking legs on females, and in males, they are modified into reproductive organs, called palpal bulbs,” Hendrixson said. “They are kind of similar to turkey basters, or something like that.”

The male, once he reaches maturity, builds a “sperm web” before leaving his hole. He deposits a droplet of sperm onto this silky web, via an opening on the underside of his belly called an abdominal genital pore. Then he takes his pedipalps, and dips them into the sperm that he just deposited on the web, and absorbs the sperm into the papal bulb.

Laden with this precious cargo, he sets out to find a receptive female.

Hendrixson and his fellow tarantula experts don’t understand everything about how the male tarantulas find the females. “They have eight tiny, tiny little eyes. They don’t see very well,” Hendrixson said. “They are randomly walking around, and maybe they come across some silk or pheromones or something that the females have left behind.”

If the male tarantula is fortunate in his wanderings, he will eventually find his way to a little round hole in the ground that is the entrance to a female tarantula’s burrow.

The male vibrates his legs, transmitting vibrations through the soil. The female, deep in her burrow, will do same thing back, and will eventually emerge to meet her new boyfriend.

Then — cue the Kenny G — they do the deed. Both spiders rear up with their first legs raised against each other, while the male tarantula grasps the female with his hooked front legs, arches her backwards in an awkward position, bends his palpal bulb and inserts his sperm-laden pedipalps into her genital opening on the underside of her abdomen.

Both sexes of spider “have genitalia in the same location,” but because the male lacks a penis, he must be able to transfer his sperm to a different part of his body in order to deliver it to the female. “It is a secondary direct transfer of sperm,” Hendrixson explained. 

While mating is underway, “it is almost like the females are in a trance,” Hendrixson said. “They don’t resist it.” But at some point, the male senses she is no longer in a trance-like state and he knows that he needs to get out of there to avoid becoming a post-coital snack (another advantage to having long legs).

If the male is lucky enough to get away, he may survive and continue his walkabout for several more months before he dies.

As for the female, “she is usually pretty aggravated at that point, and will make her way back into the burrow,” Hendrixson said. “If she has been feeding well, she is less inclined to attack the male.”


The female tarantula has special organs where she stores the male’s sperm, called spermifici. She holds onto the sperm through the winter, and at some point the next summer, in June or early July, she will begin spinning a cocoon inside her burrow — a thin film of silk — where she lays her eggs and releases the sperm she has been storing.

She then wraps the fertilized eggs up and makes a silk-covered cocoon like a little spider egg burrito. She will guard the egg sack obsessively, regulating its temperature and humidity by taking it to the entrance of the burrow to air it out, then taking it back down inside the burrow if it needs more moisture.

“We have no idea how they know to do that,” Hendrixson said.

A couple months later, the baby spiders start to emerge. “The little ones will come out of the big cocoon and hang out with Mom for a couple weeks and then disperse,” Hendrixson said.

Grand Canyon black tarantula hatchlings are about the size of a pea, and don’t yet have the adult black-and-red coloration. “They look kind of tannish, and are not very hairy, but are very easy to recognize,” Hendrixson said. “They have a giant black patch of really dense, short hairs on their back end that are fully formed and very conspicuous.”

A typical batch of babies ranges from 200-300 hatchlings. Some tarantula species in North America have more than 500 hatchlings at a time, while South American tarantulas may produce more than 1,000 in a single batch.

“You can count on one hand how many will survive to adulthood,” Hendrixson said. “They are picked off by just about anything, if they haven’t established a burrow yet.”

The babies will sometimes even eat each other; indeed, this fratricidal urge could be what triggers baby tarantulas to begin leaving their mother’s burrow. “If they are together much longer, they’re going to get hungry, and the easiest thing is to take down something their own size,” Hendrixson pointed out.

When the babies do abandon the nest, they exit all at once, in a single file line. “It almost looks like little ants,” Hendrixson said. They don’t go very far, walking only a short distance before building their own burrows, so it is not unusual to find little colonies of tarantulas.

Besides occasionally feasting on each other, tarantulas will prey on anything they can overpower that happens to walk near their burrows. Although they have pretty poor eyesight, their hairs allow them to sense the vibrations of their prey. They will sit at the edge of their burrow and wait for something to come by, then lunge out with their pedipalps and pull their prey down into the burrow.

“Insect, arthropod, arachnid: anything they can overpower, they will feed on,” Hendrixson said. He has even found evidence of small snakes, lizards, and mice in the burrows of larger tarantula species in Arizona and Texas.

The way they feed is kind of fun. Tarantulas and other arachnids have tiny mouths and can’t take in solid food. Instead, they inject their prey with a dual-acting venom that both kills and liquifies it.

“Spiders have a special type of stomach, a pumping stomach,” Hendrixson explained. “To some extent they are vomiting digestive juices into the wound in the prey. The digestion therefore occurs outside of the spider’s body, and the spider will slurp up what is remaining.”

In the wild, tarantulas try to hunt nearly every day. In captivity, though, they can go for months without feeding, suffering very little weight loss, and continue to look healthy. Hendrixson suspects that wild spiders, too, have adapted to a “feast or famine” lifestyle, especially in cold, high elevations like southwestern Colorado.

When it starts to get cold and snowy, they plug themselves up in their dens for the winter. “It’s not hibernation, just a period of inactivity,” Hendrixson said. “They sit in the bottom of their burrows, and wait,” hunkered down with no food, from December to March or April.


The number one, most common misconception about big hairy “charismatic” spiders like tarantulas (and even little house spiders, for that matter) is that they are out to get people.

From JK Rowling’s Aragog to JRR Tolkien’s Shelob, to the infamously silly tarantula episode of “The Brady Bunch” and classic horror flicks like “Arachnophobia” and “Tarantulas: The Deadly Cargo,” “Media and movies have made spiders and tarantulas to be bloodthirsty villains,” Hendrixson said.

The scientist and arachnophile in Hendrixson would like to set the record straight. “Tarantulas are venomous, but that venom is used to incapacitate small prey, insects, other arthropods,” he said. “They did not evolve to feed on humans. There are some African and Asian tarantulas whose venom can cause pretty severe pain, but no one has ever died from a tarantula bite.”

In fact, Hendrixson insists, tarantulas make great pets. “They are low maintenance, they don’t stink, they don’t make noise. Throw a couple crickets in with them every couple weeks. They get most of their water from their food. They are amazing animals, and their ability to survive so long without eating or drinking is mind-blowing to me.”

Nevertheless, Hendrixson sympathizes with people like Ailene Smith who don’t share his affinity for spiders.

“Arachnophobia is real, and it is debilitating,” he acknowledged.

Surveys show that women are four times more likely to fear spiders than men. And that fear could be hard-wired. In a 2009 study published in the journal Evolution and Human Behavior, David Rakison of Carnegie Mellon University in Pittsburgh found that 11-month-old girls quickly learned to associate images of spiders and snakes with a fearful facial expression, while baby boys did not.

Hendrixson has helped a lot of his students get over their fear of spiders, and has even worked with a clinical psychologist to do exposure therapy for a particularly fearful patient. It worked.

“By the end of the session, the patient was holding a tarantula I brought in,” he said. “They are just misunderstood animals. With a lot of legs.” And venom glands. And fangs. “The more that people know about them, the less scary they become.”

Ouray County resident Lynn Padgett concurs. When her daughter Anza developed a fear of spiders, Padgett caught a hairy tarantula that had been roaming around in the West End, put it in a glass cage, and encouraged her daughter to observe it closely until she wasn’t scared anymore. Then, together, they set it free.

“When you are freaked out, the best thing is to nail it by getting closer,” Padgett said. “The tarantula was a cool guy.”


Overall, about 1,000 tarantula species have been described. The spiders are most abundant and diverse in tropical areas, especially South America.

In the U.S., about 30 tarantula species range across the west, from California to the Mississippi River. There is also an introduced species in south Florida  — a group of released pets, most likely —which have been reproducing in an orange grove and do not seem to be doing any significant environmental damage.

Brazil has the greatest number of species, including an Andean tarantula that exists at altitudes of up to 14,000 feet.

“Even in Colorado, I have collected the Grand Canyon black tarantula above 8,000 feet,” Hendrixson said. “They probably have some sort of antifreeze in their spider blood that prevents them from freezing. There is still so much left to discover.”