When the heat of summer rolls over the desert, many of its inhabitants play it cool. Humans aside, many of the wild inhabitants shift their activity periods to the cooler hours of early morning or late afternoon. Some take the evening shift and are active during the night, at times their reflective eye shine due to a car’s headlights reveal critters such as kit foxes, coyotes, mule deer, jackrabbits or even common poorwills sitting on the road.
Many small rodents such as kangaroo rats, grasshopper or deer mice and bushy-tailed woodrats may also be seen scurrying across the road. Though they try to avoid four-legged predators as best they can, sometimes these small mammals fall prey to other nocturnal denizens – snakes.
Like their prey, snakes may also be avoiding the intense heat of day. Though these creatures and their reptilian relatives the lizards are cold-blooded, they too have temperature limits as to what they can tolerate.
Being an ecotherm, or cold-blooded creature, means they regulate their body temperature from external sources of heat rather than through metabolism. Sunlight, air temperature and reflective heat from sandstone or pavement contribute to this outside source of heat. With a low metabolic rate to start with, a reptile’s energy needs are also low. Staying warm is easy in this summer desert environment – it’s overheating that is a concern.
Coiled up in the shade of shrub or sandstone boulder, toes lifted off of hot sandstone, resting through the mid-day hours, these are different strategies that reptiles use to avoid going mad in the noon-day sun.
So who is out and about during the day? When I worked for the Park Service, I usually told people they’d be lucky to see a rattlesnake. Most didn’t understand my point of reference – I can think of only a hand-full of times when I encountered a rattlesnake on the trail. The midget-faded rattlers seemed to either slink away or stay silent as they get stepped over. Really, most of my snake encounters were during nighttime patrols in Arches NP. I’d keep an eye out for the snakes stretched across the road and whenever I encountered one, I’d usher it across the road.
Though seeing the snakes at night was cool, I’d probably pick the small side-blotched lizard as the reptile I admired the most. Smallest of the regional lizards, the side-blotches would appear early in the season or during warm spells in winter. Their small body size didn’t need much to warm up, so they could appear when temperatures were too low for other lizards. They would fall prey to their larger cousins – leopard lizards with their spotted hides or western collard lizards with their unbelievable color scheme of yellow heads and turquoise bodies – but they were the most common lizard I’d encounter.
Of course, the whiptails with their streamlined bodies and long tails were also pretty cool. One species called the northern or plateau striped whiptail had a distinct bluish tail which could disarticulate should a predator grab hold of it. The flopping tail kept the predator occupied while the lizard ran away. To live another day, as the song goes.
So during a warm summer day in June, expect to see lizards and snakes out and about. The other wildlife may be hidden, but their time in the sun will come. Maybe just earlier or later than you’d like. .