Of Snakes and Carnivorous Plants in the Blue Hills

4-24-10. Walking around Ponkapoag Pond in the Blue Hills (10 miles south of Boston, MA), we spotted several of these vicious-looking snakes, basking in the sun on the rocks at water's edge. When disturbed, one of them slithered into the water and swam quite gracefully away.

Like hundreds of others, we initially mistook this non-venomous snake as a cottonmouth or water moccasin. With a quick check on our iPhone, we learned it wasn't a cottonmouth at all. Later, at home, I discovered it was a common snake, the Northern Water Snake (Nerodia sipedon).

The Northern Water Snake is common in the eastern U.S. It inhabits lakes, ponds, rivers, and streams of many sizes. They are active both day and night, hunting for small fish, frogs, worms, leeches, crayfish, salamanders and young turtles. They also control populations of smaller animals, such as mice. Otherwise, the walk was relatively bereft of wildlife -- no birds at all and only a few chipmunks, butterflies and a bumblebee. But Pam, Pete, Jane and Claire enjoyed the green dot trail, the AMC cabins and the numerous granite rock outcroppings nonetheless.

Claire and I waded out on the Ponkapoag Bog Boardwalk and found ourselves behind a group being led by a Harvard University biologist. Thus we learned about and saw firsthand two carnivorous plants - the pitcher plant and bladderwort. Unfortunately I didn't take photos of either.

The bladderwort, typically found in acidic, shallow freshwater where nutrients are scarce, supplements its diet with an occasional insect or other small organism. It does this by trapping small aquatic creatures in its small oval bladders, which are attached to the underwater capillary-like leaves. When prey touches the trigger hairs, the bladder expands, sucking in the animal. It is then dissolved within the bladder.