OUR VERY OWN BOA CONSTRICTOR

John M. Regan

The big serpents loose in the Florida swamplands have been in the news lately and people down south are understandably concerned about these big constrictors ( please see note below). They are a real hazard.  Now I doubt that any of these big snakes could  survive one of our Northwest winters (or even summer for that matter) but it is worth noting that we have a very interesting constrictor of our own - the Rubber Boa, Charina bottae.

At a maximum length of less than three feet our boa constrictor is hardly a threat to anything but mice and other very small animals. They are, however, true constrictors and member or the Boidae family of snakes that include the giant pythons and boas of the world.  As you may suspect our representative gets its name from the rubbery feel of its scales and body. As you can see from the photographs the scales of this snake are large, quite smooth and glossy. Compare this to the rough keeled scales of the garter snake and the difference in texture is obvious.

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With its generally dull brown color (young are pinkish), small size, docile nature and retiring ways our northwestern constrictor does not come across as a very exciting reptile. And I suppose it’s true that our boa is never going to make headlines. But C. bottae does have a couple of very unique features. First there is its range. We tend to think of boas and pythons as denizens of tropical climates, and for the most part they are. But the rubber boa has a range that extends throughout the northwest region of the US and into southern parts of Canada as well.  They are reported to do well and are active even in temperatures in the fifties. Let’s see a reticulate python handle that.

The rubber boa’s most unusual and most famous feature is its tail. Stumpy, blunt, and heavily boned it sort of looks like another head, hence the snake’s nickname as the “two headed snake.” Even more odd is the reported use of this appendage as a defensive weapon. You’d expect such a thing to be used to fool predators but according to the Peterson Field Guide “Western Reptiles and Amphibians” and other sources the snake uses its tail to “stab” at mother mice while it dines on pinky babies. The snake is also known to roll into a ball if threatened and strike with this tail.

Note the smooth glossiness of this captive specimen from Northwest Trek as opposed to the keeled scales of the red spotted garter snake on the right.

Rubber boas are not rare or endangered but the casual observer should not expect to see one.  Although they are well adapted swimmers and climbers and inhabit many different types of terrain these snakes tend to be nocturnal and spend the daylight hours tucked away underground or hiding under logs. They also tend to clump together in large numbers in certain places but seem to be non-existent in others.

NOTE: Although this recent invasion is chalked up to snakes that escaped during Hurricane Andrew in 1992 I believe the actual invasion began long before. In the 1970s during a visit to Everglades National Park I saw large iguanas lounging around the swamp as if they owned the place already, and I witnessed spider monkeys running loose on private zoos.  And I must confess that as a teenager in Orlando I once released a South American boa that I had as a pet.

References:

Peterson Field Guide, Western Reptiles and Amphibians, Third edition.

Washington State Dept of Natural Resources: http://www1.dnr.wa.gov/nhp/refdesk/herp/html/4chbo.html

Washington Department of Fish and Wildlife: http://wdfw.wa.gov/living/snakes.html

HOOAH

Jack

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