Timber rattlers: Shy, threatened, essential

Editor’s note: Timber rattlesnake expert William S. Brown contacted the Adirondack Explorer after publication of a story about an apparent uptick in Adirondack snake sightings this year, concerned that people might seek to harm the rattlers. What follows is his description of a usually elusive creature that has long played a role in the park’s ecosystem, and is protected by state law.

By William S. Brown

In my 40-year study of timber rattlesnakes in the southeastern Adirondacks, I have published a number of scientific papers on the life history and reproductive biology of this species. As part of this work, we have made an effort to relocate so-called “nuisance” rattlesnakes over the years, a public-private program that has saved more than 95% of the hundreds of rattlesnakes that we have rescued from campsites and private properties.

What is evident from our ongoing recovery program is that the numbers of rattlesnakes captured and relocated is quite variable from year to year, generally ranging between 10 to 15 snakes per year, but fluctuating widely. This year, whatever environmental factors might be at play, is simply one of those rare years when a few more than the typically small number of snakes are encountered.

Following is an explanation of the snake’s natural history and behavior.

Distribution and status

In New York State, timber rattlesnakes are distributed in some two dozen counties; many populations were extirpated throughout the state over the past two centuries. The species is listed as threatened and is fully protected under New York State law. In the northeastern sector of the state, where the author’s field study is taking place, timber rattlesnakes are part of ancestral populations which have been in continuous existence for approximately 8,000 years following climatic warming and withdrawal of the most recent glacial ice sheet (the Wisconsinan glacier), followed by the development of Appalachian oak-hickory forest as prime habitat for the species.

Seasonal habits, movements and diet

Timber rattlesnakes hibernate through the winter for seven months, October through April, in underground retreats known as dens. A den enhances winter survival and maintains a stable population. After emerging, the active season lasts for five months, from May through September. Each spring, the snakes make long‑distance migrations (up to 3 miles) between their winter dens and their summer foraging grounds. In their deciduous forest habitat, timber rattlesnakes are cryptic and are seldom seen. The snakes are important predators of small mammals (shrews, mice, voles, squirrels) and thus play an important role in the natural food web and energy dynamics of the ecosystem.

 Life history and survival

Over the past 40 years, the author’s field research is based on capturing, marking, and recapturing individually identified snakes. The work has revealed new information on the Timber Rattlesnake’s life history, generally described as being a long-lived and slow-reproducing species. Maximum confirmed ages exceed 40 years in the wild. Females do not reproduce for the first time until an age of 9 to 10 years. Adult females have a low birthing frequency, reproducing only at 3-year or longer intervals and giving birth to litters averaging 7 to 8 offspring. Due to the energy demands of reproduction, only about one-third of adult females are able to reproduce more than once during their lifetime. Capture-recapture modeling studies show that the survival rate in the first year is low (about 50–60%), and in older snakes annual survival is high (about 90%).

Behavior and interaction with humans

The snake’s behavior contributes to the low danger of rattlesnake bite to hikers or campers while they are in rattlesnake country, and to homeowners whose property is within the range of the snakes. Use common-sense precautions: watch where you sit, step, and place your hands. Shy and retiring, timber rattlesnakes normally are not aggressive and will attempt to escape. In an encounter with a human, if a rattlesnake’s path of movement is impeded, it may continue to move on a given course which can be wrongly interpreted as an “attack.” However, if provoked or disturbed, or if its escape route is blocked, a timber rattlesnake may hold its ground, coiled and rattling, until the human intruder disappears.

 Nuisance rattlesnakes

In the summer mating season (July and August), male rattlesnakes move frequently and may be found crossing roads or hiking trails and making unannounced visits to houses (lawns, rock walls, bird-feeding areas) and campsites. The best advice for homeowners and campers is simple: Do not approach or molest a rattlesnake—if you see one, leave it alone. The Department of Environmental Conservation (DEC) forest rangers and game wardens (environmental conservation officers, or ECOs), town animal control personnel or trained biologists may be called to capture and relocate a nuisance rattlesnake.

Snakebite

The bite of a timber rattlesnake is a serious medical emergency; the venom attacks the blood’s clotting ability and is tissue-destructive. Emergency procedures by trained medical personnel greatly reduce the risk of fatality. Hospitalization is required to receive antivenin intravenously, the definitive modern treatment. If bitten, the best nationally accepted first-aid advice is simple: Go to the nearest hospital immediately.

William S. Brown is an adjunct research biologist with the Darrin Fresh Water Institute.