Using a photo from the city, the state herpetologist identified it as a northern watersnake, a much more common, nonvenomous snake. The post Report of rare, venomous snake in Mass. city likely ‘a case of misidentification,

The snake reported to have bitten two dogs in Attleboro, MA on July 9 is most likely not a rare venomous snake, state wildlife officials said.

It wasn't on Cape Cod, but the copperhead snake bit two dogs in Massachusetts outside its usual habitat. Here's how to identify it.