Friday, January 1, 2010

This Is Why You Should Never Kill A Blacksnake!

It ain’t easy being a snake. If people don’t run away screaming at the sight of you there’s a good chance it’s only because you’re about to be killed with a shovel. For serpents, your average citizen of the southeastern United States is very hard to please. But in the eyes of many, some species at least do have one redeeming quality, that being they eat other snakes. The lives of many kingsnakes, for example, have been spared because the species is ophiophagus (this is the scientific term for individuals or species that eat snakes; I myself have been known to be ophiophagus once during a camping trip a few years ago, but that’s another story).

In addition, another ophiophagus snake around here is the Indigo Snake, Drymarchon corais couperi , famous in particular for their ability to eat rattlesnakes. Pit vipers may actually even be their preferred prey. Since rattlesnakes have a shot at being the most reviled organisms on the planet, indigo snakes, in turn, enjoy considerable popularity (although this relative popularity has not been enough to keep populations from declining precipitously over the last few decades). The indigo snakes’ rattlesnake-eating behavior is on full display in an e-mail I’ve received several times, often entitled something along the lines of, “This is why you should never kill a black snake”.

The series of photographs shows a large indigo snake, identified by its uniform dark body, orange-tinted chin, and dark line running below its eye, consuming a Western Diamondback Rattlesnake, Crotalus atrox. Many have identified the snake in these pictures as a kingsnake, Lampropeltis getula, which it certainly is not. Although kingsnakes may also eat rattlesnakes, they will typically have white or yellow chains or bands along the length of their body. The rattlesnake, sometimes erroneously identified as the Eastern Diamondback Rattlesnake, Crotalus adamanteus, is easily identified by the black and white striped tail that is characteristic of the western species. Since it's a western diamondback rattlesnake, we know that this picture did not originate in the southeastern United States, where they do not occur. We also know that this can't be an Eastern Indigo Snake, Drymarchon corais couperi, because they aren't found where Western Diamondback Rattlesnakes live. This must be a Texas Indigo Snake, Drymarchon corais erebennus. If the picture was taken in the United States, it must be from south-central Texas, the only area in the country where the species occurs (both species also occur in Mexico).

Many commonly inquire how Indigo Snakes are able to safely consume rattlesnakes, dangerous predators in their own right. I don’t think it’s accurate to suggest Indigo Snakes are completely immune to rattlesnake venom, but it’s probably safe to say they are less susceptible to its effects than other animals. When a prey snake is located, an Indigo Snake will grasp its head and chew it into oblivion (demonstrated in the below picture) before swallowing it whole.

So long and Happy New Year!

1 comment:

ramblingwoods said...

I thought I had read that some rattlesnakes were kind of sparse in some areas of the SW due to being killed and loss of habitat. I don't live with any dangerous snakes here in New York so I don't have to decide what to do, but I think I would want to leave the snake alive....Michelle