A view from the Skyline Trail in Blue Hills Reservation.

It was a bright afternoon in May. I was hiking up a steep trail near the crest of Buck Hill in Milton, noticing about how warm the rock ledge at my feet felt, having absorbed the heat of the sun all day, and musing on how nice it would be to lie down upon it. And then I remembered that snakes like to stretch themselves out over warm rocks too . . . And that I had read something recently about rattlesnakes in the Blue Hills. . . And that maybe I should watch my step.

Given the fact that there were probably a hundred other hikers on the trail to Buck Hill that day, there wasn’t any cause for concern. Snakes don’t gravitate toward well-trafficked areas. But it got me thinking that I should educate myself more thoroughly on the matter. To put it mildly, I’m not fond of snakes. It would be better to know what to expect than to ruin a hike by imagining them lurking around every corner!
We typically associate rattlesnakes with the desert, and do not expect to encounter them close to home. However about 200 timber rattlesnakes currently reside in Massachusetts. Most often they inhabit wooded mountainous areas with steep rocky ledges and ample populations of rodents . . . although they are sometimes found in fields and wetlands too. Populations in our state are concentrated in the Berkshires, the Connecticut River Valley and the Blue Hills. Nationwide, they make their home throughout much of the eastern US, as far west as central Texas in the south, and to Wisconsin in the north. While they are abundant in the southern Appalachians, here in the northeast, populations are quite small.
The timber rattlesnake hibernates for the colder half of the year, but becomes active in Massachusetts around the middle of April. After emerging from the underground crevices in which is spends the winter, it makes its way onto rock ledges where it can bask in the sun to keep warm. (Like many snakes, the timber rattler is ectothermic, meaning it cannot regulate its own body temperature.) In the spring, activity is minimal, although some mating does occur. After mating, the snakes move away from the den — males to dense forest, where the hunting is good; females to fields and less-dense forest, where temperatures are warmer. Baby snakes are born alive after about 4-5 months. They all return to the den in September or October, depending on the weather. The average life span for a timber rattlesnake is 10-15 years.
A brown Timber Rattlesnake. (Photo credit Anne Stengle/Mass Wildlife)
 The standard description of a timber rattlesnake includes the phrase “pit viper,” which sends chills up my spine. If you’re imagining a teeming pit of angry, venomous snakes (as I first did), please take my hand and we’ll back away from that erroneous image together. A timber rattlesnake is large – three to five feet in adulthood, 8-16 inches a birth, with a broad triangular head and rough-looking scales. It can range in color from black or brown to rust or dark yellow. The underside is light in color, sometimes with dark flecks. It has bands across its back and sides, but none on its head or face. Its tail is solid black, with a rattling structure at its end that grows with each successive shedding of skin, but is sometimes lost in that same process. The term “pit viper” refers to the pits on either side of its head – super-sensitive nerve endings that can detect radiant heat.
Timber rattlesnakes don’t eat people. Not even small ones! They prefer mice, chipmunks and other warm-blooded rodents, plus sometimes birds, bugs and amphibians. They hunt by day in the spring and fall, but become nocturnal in the summer, when their prey becomes more active at night. Here the sensory pits are especially useful – they help the snake to detect warm-blooded prey in the dark. Timber rattlesnakes see pretty well, especially when an object is moving, but they can also track prey via its scent, or by sensing vibrations in the ground.
A timber rattlesnake has two large fangs at he front of its mouth, plus a number of smaller teeth along its jaw. The fangs, which fold back onto the roof of the snake’s mouth and are covered by a sheath when the jaw is closed, are conduits for venom. Hunting consists primarily of lying motionless – watching and waiting — with intervals of prowling. Attacking prey comes first. Injecting venom, the volume of which the snake can control, is a secondary measure.
When it comes to humans, a timber rattlesnake will strike and bite only as a last resort. When disturbed or threatened, it will rattle its tail, which should be enough to send most people packing. The timber rattlesnake prefers to be left alone, and will back away from a human if possible. It will probably fight back if touched, though. It’s helpful to know that the last reported fatality from a timber rattlesnake bite in Massachusetts was in 1791.
Due to declining populations, the timber rattlesnake is now an Endangered Species in Massachusetts. Its habitat has been diminished over the years, and a lot of lives have been lost through ill-fated road crossings. Just as much of a threat, however, is hunting. Whether it’s snake collectors, or people who come upon a snake and kill it out of fear, timber rattlesnake numbers have been greatly reduced in the past 25 years.
You may have heard recent news reports about a statewide effort to protect timber rattlesnakes. They would be captured in the wild as newborns, raised in captivity (at the Roger Williams Zoo) and then released to their birth area when they are old enough to fend for themselves. (This would amount to no more than ten snakes released per year.) Nothing controversial, until the release plan changed and there was talk about designating Mt. Zion, a 1400-acre island in the Quabbin Reservoir without human access, as their new home. “Rattlesnake Island” sounds like a horror movie, so there was a fair amount of public outcry. The issue remains undecided.
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by Kezia Bacon

April 2016 
 

Kezia Bacon’s articles appear courtesy of the North and South Rivers Watershed Association, a local non-profit organization devoted to the preservation, restoration, maintenance and conservation of the North and South Rivers and their watershed. For membership information and a copy of their latest newsletter, contact NSRWA at (781) 659-8168 or visit www.nsrwa.org. To browse 20 years of Nature (Human and Otherwise) columns, visit http://keziabaconbernstein.blogspot.com