A Western Diamondback Rattlesnake in ambush in a sandy wash on a very hot night.
This sand is much cooler than the surrounding rock, with smaller particles that lose energy more quickly. While it’s easy to think of reptiles as ectotherms always looking for sources of heat, they’re just as often looking for ways to lose it. Thermoregulating is more like a behavioral thermostat, and areas like this help.
A large male Western Diamondback Rattlesnake cruising through dense vegetation, on the lookout for others that may be near. At this higher elevation den in the late fall, the females are already tucked into rock crevices and caves. All that remain on the surface are the largest males, patrolling for rivals, and getting into the occasional fight. This one finished its loop and settled back into the sunny spot it prefers for awhile, before doing it all again about an hour later. Why wait until spring to fight for the good spot, when you can do it in the fall?
Three of the half dozen or so Western Diamondback Rattlesnakes that occupy this den each winter. These snakes spend a lot of time during the early spring basking and making short movements to thermoregulate and for social reasons, where they are vulnerable to predators and other threats.
A thin Western Diamondback Rattlesnake stopped for a moment while crossing a dirt road. Often, this behavior is misinterpreted as “sunning”. While snakes may stop to bask like this, in many cases, it’s just that the snake saw the observer first and stopped moving in hopes the perceived predator will not notice it. They don’t know what roads and trails are, however, so imagine it from their perspective: moving along, headed home after a long night of ambush hunting … a monster appears in the distance and comes directly to you! It’s no wonder they then become defensive. But as always, the easy way to remain safe is just not to bother it.
