"Outdoor Story" - Hair Raising Rattler Research

The "Outdoor Story" is a newspaper column Erv and I take turns writing every other week for Socorro's El Defensor Chieftain. This is my most recent! Sandra

Just like every other critter, large and small, rattlesnakes have their place and purpose on this earth. Still, they could use better PR because they often get a bad rap. From the serpent in the Garden of Eden to the asp that killed Cleopatra and in movies like “Snakes on Planes,” they are the bad guys. Little is said about their usefulness in controlling rodents and other small mammals, or the role of rattlesnake young as prey for hawks, eagles, roadrunners and even wild turkeys, as well as mammals including coyote, fox and badger.
Rattlers do warrant caution – their bite can be fatal if not treated, but they don’t seek humans and only bite us when surprised or threatened. Humans, on the other hand, have a long history of hunting and killing snakes, sometimes just for entertainment.
The Western Diamondback Rattlesnake is the largest of the Southwest desert rattlers; adults average 3.5 to 4 feet. They have a venomous snake’s characteristic flat-triangle head shape and their color ranges from gray-brown to pinkish with diamond-shaped body blotches. Their tails have distinctive bands of alternating black and white (coon-tail) that fade with age. Rattles grow segment by segment, each one a remnant of a shed skin. It’s a myth that the segments show a snake’s age; they can shed 2-3 times a year.
Diamondbacks generally hunt at night and early morning, positioning themselves to ambush passing prey. Having poor vision, they use their flicking tongue to “taste” the air by pulling chemical molecules into the Jacobs organ where they are translated into smell and used to track prey. Heat-seeking facial pits (hence the name pit viper) guide their strikes. Prey includes rodents like mice, prairie dogs and ground squirrels or the occasional bird or lizard, which they swallow whole. They can go several weeks before feeding again.
Rattlers are solitary outside of mating season and winter denning. In late Oct. they seek den sites where they burrow in quasi-hibernation with other snakes until early March. Live-born rattlesnake young are self sufficient, capable of delivering a venomous bite from the moment of birth – they only spend a few hours with their mother. It’s another myth that the young deliver more concentrated venom.
Enough background – on to the hair-raising research! In the fall of 2009 Lorraine McInnis, a UNM biology graduate student began radio tracking Western Diamondbacks at the Bosque del Apache to document their general movements and locate winter dens. She is radio-tracking 16 at the current time and hopes to track 25 individuals over a two year period. An additional 200 Diamondbacks have been tagged with microchips which can’t be radio-tracked but provide additional data.
The stimulus for Lorraine’s research was management of human/snake interaction - rattlesnakes are a safety concern in visitor areas of the refuge but she has found it an opportunity to explore aspects of rattlesnake biology that are not fully understood. Lorraine explains that any animal occupies a particular location for access to food, shelter, water and/or for breeding but snakes’ habitats and movements are also affected by daily and seasonal temperatures. “Cold blooded” reptiles externally regulate their body temperature.
The hair-raising part of all this is that each one of these 200+ snakes must be captured, examined and measured, then carefully radio-tagged and re-released to its original location. (Only those found in visitor areas are relocated elsewhere.) The radio- tagged snakes are then tracked daily no matter how remote or difficult to access. Trackers must take great care to neither disturb the snake nor get bit themselves. Erv and I have been greatly impressed by Lorraine’s skill, focus and caution working with the snakes but, as volunteer help, we always find it a hair-raising experience!
It has been shown that long distance relocation has a negative impact on a snake’s natural movements and even their survival. Lorraine’s detailed field research on Western Diamondback denning sites and normal patterns of movement will provide important information for Bosque del Apache managers to safely reduce human/snake interaction with the least impact on the snakes. Refuges are, after all, for wildlife - including rattlers!