PULLMAN, Wash. — Biologist Ken Kardong has studied reptiles for decades, with a special interest in rattlesnakes. He knows how they strike their prey, what their venom does inside an animal, and how the snakes find their prey after the victims have run off to die.
As an expert in the rattlesnake research community, Kardong is in touch with the news from around the west about the snakes, and he’s heard scattered reports that the upcoming season for rattlers in the Inland Northwest may be a significant one.
“Anecdotally, I’ve heard the snakes are expanding their ranges,” he said.
Few people are actually bitten by rattlesnakes each summer. Most people who are bitten deliberately seek out the contact, often for hatband trophies.
“A young man is typical, stopping on the road for what he thinks is a dead rattlesnake, but turns out to be a live one,” Kardong said.
Studying and handling rattlesnakes for a living has some obvious hazards. Kardong has been seriously bitten on two occasions over the decades, recovering both times with the help of anti-venom injections.
What you may have learned as a child about treating snakebites with razor blades and tourniquets or nooses of fishing line is far from the recommended practice today.
“Anyone who is bit should calmly go to the nearest hospital,” he said. “That’s all you should do. The doctors will evaluate how much venom you have received from the bite, and treat you accordingly.”
When rattlesnakes bite humans it’s a defensive measure. They are trying to protect themselves, rather than hunt down a meal. About 20 percent of bites to humans are “dry,” meaning no venom is injected. At the other extreme, about 20 percent of bites to people involve a big dose of poison. Because people are so much larger than rodents, most people survive a rattlesnake bite even without treatment. But it’s a significant medical event by any standard and merits a trip to the hospital.
One aspect of Kardong’s research involves how rattlers sense their prey. They can see light, of course, but they can also sense infrared radiation using small pits located below their eyes. Infrared radiation is given off by any warm body.
“So the snakes can see in the daylight, but also ‘see’ prey at night or underground in tunnels from the infrared,” he said.
The venom of rattlesnakes does more than kill the prey. It also acts as a digesting enzyme so that when the snake swallows the dead prey, it’s digested from the inside out as well as from the outside in. The system works so well and thoroughly that what the snake finally expels is often only the prey’s teeth and hair.
After striking a rodent with its fangs, a rattlesnake immediately throws itself off the prey, so it’s not mauled by the rodent’s incisors. That’s a good strategy in terms of avoiding injury to the snake, but it means the prey is likely to scamper away before dying, giving the snake the significant task of relocating it.
The snake’s tongue helps it to track the dying prey. The flicks of the tongue bring back scent particles that are deposited in an organ in the snake’s mouth that registers them.
“Rattlesnakes can be as good or better than bloodhounds in trailing an animal,” Kardong said.
Rattlesnakes are most active at night, and Kardong has collected them during summer evenings over the years for his research lab. But even though he has had decades of experience working with rattlesnakes, the sight of one near his feet still evokes a major physical response.
“I think I can jump about eight feet,” he said. “I may not be scared of them at an intellectual level, but my reflex is still there.”
Apart from people seeking trophies and researchers studying rattlesnakes, the people Kardong thinks are most at risk of rattlesnake bites are bird-watchers.
“They are looking up, not down,” he said with a smile.