TIMES-LEADER (Wilkes-Barre, Pennsylvania) 01 July 07 Bearing young an exhausting, trying time for timber rattlesnakes (Tom Venesky)
Rick Koval’s instructions were simple, yet vital: walk in single file and watch where you step. It’s about all you need to know when you are walking along the boulder-strewn banks of a lake that is a haven for timber rattlesnakes.
On Thursday I accompanied Koval, who is a naturalist with the North Branch Land Trust, and Pennsylvania Game Commission biologist Kevin Wenner to a spot in western Luzerne County to count timber rattlesnakes. Koval periodically counts snakes in the area as part of the Timber Rattlesnake Den Assessment for the Pennsylvania Fish and Boat Commission.
Although we wanted to find as many snakes as we could, we hoped to find gestating females laying among the rocks soaking up the sun to heat their embryos. Because timber rattlesnakes are a species of special concern in the state and the snakes are vulnerable to human intrusion, Koval asked that the location not be disclosed.
A 20-minute trek across the waterway via kayak landed us on a rocky shoreline that extended steeply uphill into forest. After we pulled the kayaks on shore, Koval gave us the crucial instructions and we slowly stepped from boulder to boulder looking for anything venomous.
It didn’t take long for the rocky shoreline to yield results.
As I followed Koval from stone to stone, a brief buzzing sound a few feet away stopped him in his tracks.
“There’s one sticking out of the rock in front of us,” he said.
Partially sheltered by a tuft of grass 5 feet away lay a coiled-up yellow phase female. Aside from the brief warning it gave Koval, the 36-inch snake snake didn’t rattle and didn’t move. As we snapped photos, the snake didn’t even seem to care that we were there.
It had more important things to worry about.
According to Koval, the female snake was “thermo-regulating,” a process in which gravid (pregnant) rattlesnakes soak up solar heat to develop their unborn young.
“Rattlesnakes bear their young alive, they don’t lay eggs,” Koval said. “They basically incubate their young internally by absorbing solar energy.”
Rattlesnakes breed in the summer and as soon as the gravid females emerge from hibernation in the spring they begin thermo-regulating the embryos before giving birth in September. Koval said the particular female we found probably didn’t eat since early last fall.
“They don’t eat before hibernation because they can’t digest food when it’s cold. If they hibernated with food in their stomach, it would just decompose and poison the snake to death,” Koval said.
The gestation period takes an exhausting toll on the female rattlesnakes, which is why they only give birth every three to five years. Between gestations, the snakes spend their time preying on small mammals to build up their fat reserves to survive the next pregnancy.
While Koval sat on a large boulder overlooking the snake, Wenner spotted another yellow phase partially tucked under the stone below Koval’s foot. Like the first snake, this one didn’t move and didn’t seem to care that we were there.
“The spot on the shoreline traditionally has the highest density of pregnant female rattlesnakes in the county,” Koval said. “The rocks offer a lot of solar heat, and there are dens less than 100 yards away, so it’s convenient.”
Although timber rattlesnakes are managed by the PFBC, Wenner does work with some landowners who would like to manage their property to protect rattlesnake habitat.
He said Thursday’s location was ideal because of the close proximity of the den and gestation sites, but he did see room for improvement.
“If the landowner expressed interest, I would recommend removing the trees that don’t produce mast and encourage the growth of oaks and berry-producing shrubs,” Wenner said. “The mast and berries attract small mammals, which in turn give the rattlesnakes a consistent food source.”
Storm clouds begin to roll in after we found the second snake, so we decided to continue up the rocky hill to a den site in the forest. Koval said last year he found around 40 females and 160 neonates (newborn snakes) around the den. At certain times of the year the site is home to approximately 200 rattlesnakes, according to Koval.
That’s a lot of venom, but still we continued on.
Although we had to be careful where we stepped, Koval said timber rattlesnakes aren’t aggressive. The two females were extremely docile, but it’s still a good idea to use caution when you are between a sunning area and a den.
As we reached the den, which was nothing more than an inconspicuous hole at the base of a large stone, the rain began to fall. There weren’t any snakes around the den so we decided to head back to the kayaks.
But the rainfall turned into a downpour and several close lightening strikes erased any thought of paddling across the water back to our vehicles.
Instead, we took refuge under a huge rock outcrop about 30 feet away from the den and waited out the storm.
And just like we watched every step we took along the shoreline, Koval gave us more good advice before went underneath the outcrop.
“Check the ground carefully before you sit down,” he said.
Bearing young an exhausting, trying time for timber rattlesnakes

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