Where have Island snakes snuck off to?


The Vineyard was never particularly well endowed with snakes, at least in terms of diversity. Only seven snake species have been adequately documented here. (An eighth, the northern water snake, is documented only in my memory: I’d swear on a stack of bibles that I saw one in Sheriff’s Meadow Pond in Edgartown in September 2003. But did I have my camera with me that day?) One of these species, the garter snake, is fairly common and widespread, even occurring in settled areas. Another, the ribbon snake, is pretty common in the wetland habitats it prefers (this graceful reptile is a frog-hunting specialist). As for the rest, well, let me ask you: when was the last time you saw a snake other than a garter snake on the Vineyard?

A delightful 1976 book by James “Skip” Lazell, “This Broken Archipelago,” supports the anecdotal accounts I’ve heard of plentiful snakes on the Vineyard. Milk snakes flourished in active or recently abandoned agricultural areas (they eat mainly rodents). Smooth green snakes, while local, had pockets of true abundance. The ring-necked snake, which according to Lazell dines mainly on salamanders, could readily be found under rocks and logs. But these days, unless you’re adept at searching specifically for snakes, it’s easy to naturalize for seasons on end and not run into anything other than a garter snake. What has happened to our snakes, and what are the consequences of their decline?

The most impressive of the Vineyard’s snakes might be the best example to use for discussing the plight of this whole group of species. A beautiful, glossy-scaled animal, the black racer inhabits a wide range of upland habitats and by all accounts was once very common on the Vineyard. I bet it loved the sunny, open habitats of the Island’s sheep-farming days and the scrubby environments that resulted as pastures began growing back up into woodland.

A big black racer is an imposing snake, sometimes exceeding six feet in length. And even a smallish one is not a snake to be trifled with: while one would never launch an unprovoked attack on a human, black racers are territorial and often stand their ground when disturbed. If they feel threatened, they’ll do their best to bite the daylights out of you.

But despite the racer’s personality, it is hard to think of an animal more beneficial to human beings, or one whose decline is more regretted. The reason is this snake’s fondness for warm-blooded prey. They undoubtedly eat things – bird eggs and small birds – that one might prefer to have them leave alone. But they dine preferentially on rodents, including unpopular species like the rat and more amiable but even more worrisome ones such as the white-footed mouse, a frequent host for deer tick nymphs and a reservoir for the microbe that causes Lyme disease.

Our black racer population, in other words, once represented a stiff headwind for several small mammals that humans generally agree need to be kept under control. But in my 16 years on the Vineyard, I’ve seen exactly three of these well-optimized mouse-killers: two live ones (or maybe the same one twice) in the state forest, and a dead one, a promising three-footer, that some idiotic bicyclist had run over, presumably deliberately, on one of the state forest bike paths.

Black racers are still out there, for sure. But relict populations that hang on for a while in developed areas eventually die out, and elsewhere reforestation has reduced the amount of habitat that is truly prime for this snake. And most importantly, a network of heavily traveled roads helped decimate the Island’s black racers, since this snake is a wide-ranging critter that loves to bask on sun-warmed asphalt. The fact that you never see a road-killed racer these days doesn’t mean they’ve gotten better at crossing roads: it simply means there aren’t many left to get hit. Our other snakes, which like the racer are generally beneficial for the Island’s ecological balance, have all suffered more or less from the same changes.

The decline of our snakes is nobody’s fault. It’s the result of countless little decisions rather than a few big ones. We’ve altered snake habitat for our own uses. We’ve unintentionally encouraged skunks and raccoons, which prey on snakes and snake eggs. We’ve removed the debris piles and stone foundations that once sheltered snakes or supported their hibernation. And we’ve stamped tire-tread imprints on multitudes of snakes as they traveled across the landscape. It’s amazing there are any snakes left at all. And it’s sad to think of the impacts the decline of these important animals has had on human well-being.