We have four watersnakes of the genus Nerodia in my neck of Florida: the Green Watersnake (N. floridana), the Brown Watersnake (N. taxispilota) the Florida Watersnake (N. fasciata pictiventris) and the black sheep of the family – the Mangrove Salt Marsh Snake (N. clarkii compressicauda.) Why are Mangrove Snakes the black sheep of the family? There are actually a lot of reasons: despite the fact that it is closely related to the Florida Watersnake – and even readily hybridizes with them in the wild, the Mangrove Snake is quite a different animal.
Despite the “watersnake” designation that the genus Nerodia carries with it, Mangrove Snakes can’t be fully classified as aquatic: semi-aquatic, yes, but the fact of the matter is they will spend quite a bit of their time resting on the boughs and proproots of Red Mangroves (Rhizophora mangle) – they are indeed a semi-arboreal watersnake. The oddity doesn’t stop there either: anyone who’s ever handled a wild Nerodia of nearly any species will attest to the genus’ poor manners. That is to say, it is not uncommon to face the piercing of a watersnake’s teeth, the sting of the subsequent musk in the wounds and the steady drip of blood thanks to their anti-coagulant laden saliva. However, of the dozens of Mangrove Snakes I’ve handled during the research for my field guide and subsequent projects, I don’t recall once having been bitten by any of these docile snakes. Then there are the morphological differences: Nerodia clarkii compressicauda possesses a range of pattern and coloration. Sometimes they look vastly different from any other watersnake, sometimes they are nearly indistinguishable from the Florida Watersnake. Banding or striping, red, black, orange, yellow and grey are all within the natural variation for the species; perhaps surpassing even the Cornsnake in its range of natural variation.
The Mangrove Snake is a species I’ve been working with a lot lately both in the Everglades and the Florida Keys (I know, life’s tough.) The nature of their habitat choice with its high structure and ever-shifting tides, as well as their semi-arboreal habits begs the question of how best to survey for them: typically, Watersnakes are most efficiently and quantitatively surveyed for using aquatic trapping methods, that is, commercial minnow traps set in the water. My current work involves looking at the efficacy of this method when compared to foot and road survey methods. Like any organism; when one dedicates time to their study – to getting to know a species both in the scientific sense as well as the deeper knowledge of a species that can only come from observing and interacting with them in the field – that species becomes exponentially more interesting.
For those who have never had the pleasure of seeing a wild Mangrove Snake, I cannot express how thrilling it is to see them on the road or draped over a mangrove proproot – they are one of Florida’s finest, and I would recommend any herper add them to their lifelist.