Cumberland biologist tracks rattlers, and mysterious fungus that's wiping them out, in TN state park
Something is killing off the timber rattlesnakes.
It also is decimating populations of northern water snakes, eastern racers, rat snakes, mud snakes, pigmy rattlesnakes, massasauga rattlesnakes, copperheads, milk snakes, cottonmouths, ribbon snakes, corn snakes, indigo snakes, kingsnakes and ringneck snakes.
Typically, snakes' worst enemies are such predators as birds of prey, raccoons, wild boars, coyotes and foxes.
But this silent snake killer is as pernicious as it is extravagant. It comes not seeking a meal but simply to steal the life of a living creature.
Cumberland University associate professor of biology Danny Bryan, known to some as "Rattlesnake Man," has been on the case.
"We know it's Snake Fungal Disease, SFD," said Bryan, who has been scrutinizing the habits of the timber rattler (Crotalus horridus) for the past 27 years. "The mystery is where is it coming from? Is it from soil? From bird droppings? Insects? We don't know.
"We know the snakes are getting it. We know the fungus is behind it, and we think it's just begun. There's a lot of unanswered questions, but we do know it's being spread snake to snake."
Thus far, the disease has been confirmed in at least 18 states including Tennessee, Illinois, Florida, Ohio, South Carolina, North Carolina, Georgia, Arkansas and Virginia, and in southern Canada.
Over the past 12 years, Bryan has kidnapped some 30 to 40 timber rattlesnakes, implanted transmitters and then released them where he found them so he could track their movements and check their health.
"I've got three timbers in the state park here [Edgar Evins State Park] with transmitters. Two of the three have the disease. I usually come once every two weeks. I pretty much know the habits of the snakes. It's been getting harder and harder to find rattlesnakes," said Bryan, who teaches intro to zoology, microbiology and biology.
About a breeding ground that he keeps a secret, he noted that after finding rattlers at the site for 13 consecutive years, he has not spotted any the past two years.
"We've got scientists all over the eastern U.S. taking surveys, and we're seeing the disease increase across the country. A lot of people don't know how devastating this disease can be. There are some of the Northeastern states where the disease has nearly caused the extinction of the snake in these states," he said.
Culprit not a critter, but a fungus
The culprit behind the disease is the fungus Ophidiomyces ophiodiicola. It shares numerous similarities with another fungus that has been spreading across the country -- Pseudogymnoascus destructans, which cause white-nose syndrome and has dispatched millions of bats.
"Most people think a disease that kills the snake is a good thing. That the best snake is a dead snake," said Bryan. "What they don't realize is what that's gonna do to the ecosystem. So we're going to see the rodent population blossom and with that comes disease.
"One of the diseases is tick-bite disease and is very bad in the West, the bubonic plague. Studies have been done that show that one rattlesnake can take out up to 5,000 ticks that can be on the rodents that they eat: squirrels, mice, rats, chipmunks.
"These are ticks that can cause Rocky Mountain spotted fever and Lyme disease. But something scarier than these that we're seeing in Middle Tennessee is a tick-bite affliction that causes an allergy to red meat caused by the Lone Star tick.
"I got it after being bit by a tick on Indian Creek two years ago. I had a loaded potato with bacon and had a reaction to it. I got tested the next day and was confirmed with the allergy. I cannot eat pork, beef, lamb, venison, squirrel -- anything that is a mammal. I can only eat poultry and seafood."
The illness is known as alpha galactose allergy, aka "alpha gal."
In April, Today.com reported, "At Vanderbilt University, the syndrome was rarely seen a few years ago. Now, the university's doctors are treating 160 patients with the syndrome."
Said Bryan, "Middle Tennessee tends to be an area where it has started to be exposed. Once you think about a rattler eating 5,000 ticks that's kind of important."
One bitten... no, twice bitten
The biologist, who has been doing everything he can to help the timber rattler thrive, has received a double whammy for his efforts. Besides contracting alpha gal, he was bitten two months ago by a belligerent male rattlesnake.
"You work with them for 27 years, and the odds are you're eventually gonna get bit. Some of the biggest experts on rattlers have been bit," he said matter-of-factly. "I got tagged. I didn't feel it. The only way I knew it, he was still hanging on my finger. He pumped me full. It was one of those freak things."
Lifeflighted from DeKalb County to Vanderbilt Hospital, Bryan received 14 life-saving vials of anti-venom. He has been left with a crooked left index as a memento of the encounter, but has no animosity toward the reptile. He encourages Middle Tennesseans to let rattlers lie should they cross paths.
"It's a two-pound animal with no arms or legs, and all it has for defense is to bite, and so if you leave it alone, it will leave you alone. Venom is expensive. It's a protein, and they have to eat to make it, and they don't want to waste it on something they can't eat.
"Their first line of defense is camouflage. He won't do anything until threatened. His second line of defense is escape. If he can't escape, he'll bite," he explained.
Trying to find his rattler cast
On a cool morning in October, Bryan walks in the woods at Edgar Evins State Park. He holds an antenna above his head, and beeps sound off every two seconds or so from a small black box that hangs from his neck. The antenna picks up a signal from the transmitter embedded within the snake.
"I've got five snakes tagged: Little Joe, Hoss, Victoria, Mary and Joan," said Bryan, who named the males after characters in the 1960s TV western "Bonanza" and the females after British queens and a French female warrior.
He first goes looking for Little Joe, a 5-year-old male, who has SFD.
"Rattlers typically go into hibernation the middle of October, but some males hang out till December hoping to get one more meal. I'm just wondering if he hasn't gone back to his den," said Bryan.
But within 10 minutes of his search, he locates Little Joe in a pile of dead leaves, perfectly camouflaged, about 50 yards away from his den near the crest of a steep hill.
"Where I see the fungus first, it is usually in the face, and then when I begin to examine the snakes, I also see it on the belly. The spots on the belly are kind of dark brown and crusty. The ones on the face more like a tumor," he said.
Bryan points to a tumor on the rattler's face.
"It is near the heat-sensing pit by the right eye which gives the fungus an opportunity to spread to the brain. I was hoping that lesion would clear up more," he said.
"This snake is skinny. He doesn't look good. A characteristic of the disease is anorexia. I'll be surprised if he's alive next year because as he goes into hibernation, the auto-immune system will slow down and that makes it easier for the fungus to grow."
Bryan worries that earlier this summer the sickly male may have discovered a gestation site three-quarters of a mile away with a female and babies and that he may have infected them.
Searching for a European royalty
Next on the search list is Mary, a 4-foot-long female, 8 to 10 years old.
"Now let's see where this gal is," he says, following the beeps. "She's pretty close. Boy, she's blending in. She's in those rocks. I got her! And this is Mary, Queen of Scots.
"She's clean. No fungus. She's really healthy. She's been foraging in the area, feeding on chipmunks. I sure hope what I suspect is not going to happen. I'm happy she's not going to that den site, the one used by Joan, who has the fungus. Fungus makes them do abnormal things."
After taking some photos of the snake, the hunter moves to another site and hefts his antenna toward the sky.
"This is Joan. She's within five feet of me," said Bryan, who has yet to spy her due to the four-feet-high dense vegetation.
Then he smiles.
"I was about to step on her. I got her. Notice, no rattle, no strike. That's typical behavior. I walked right by her. She could have tagged me if she wanted to. Course, I got boots on. Three for three. I'm surprised," he says about his rewarding walk in the park.
"In August of 2012, this was the site of the first case of confirmed SFD in Tennessee. That makes three confirmed snakes from this little area that has the disease," he said of the location.
Fresh photos and notes in hand, the ally to timber rattlers concluded, "It's all about trying to save this snake -- not just them but all snakes."
Writer Ken Beck may be contacted at firstname.lastname@example.org.