Get a Handle on the Heat

Gray fox sleeps the day away

In a matter of days the fleeting Arizona spring became summer. Step outside and notice your clothes quickly become toasty warm. The heat lays on your bare skin, weighty and insistent. If you are in the direct sun, you experience a roasting sensation. You are conscious of your breath as the heat presses into your lungs. Your eyeballs feel scratchy. It’s time to find shade. Shade can make a difference of ten degrees or more, and the canopy of even the flimsiest desert tree reduces the sizzle and glare of the summer sun. The heavy hair on a human’s head is designed to protect our heat-sensitive brain. A shade hat is a good idea and essential for the more hair-challenged among us. Our upright posture ensures that our head and shoulders bear the brunt of exposure, and keeps most of our body away from the hot surface of the desert floor. The other animals of the desert also have methods to deal with extreme heat. Many mammals including foxes, ringtails, raccoons, badgers and skunks are completely nocturnal. Bobcats, javelinas, mule deer and bighorn sheep feed early in the morning and late in the evening and seek shelter in cooler microclimates such as thick shade or under rocky ledges when the sun is high. Many desert rodents spend most of their lives in their burrows, where the temperatures are moderate. Harris’ antelope squirrels remain active during the day, carrying their tails over their backs like umbrellas. When it gets really hot they stretch all four legs out and flatten their bellies on a shaded surface to transfer heat from their bodies. You will notice birds standing tall in high temperatures to maximize the surface area of their bare legs where dilated blood vessels transfer heat away from the animal. I’ve seen doves roll on their sides with one wing up to create little sails for shade. The doves raise their young in spindly nests, little more than loose platforms. The slightest movement of air passes easily through these few twigs, cooling the eggs and the hatchlings. In this way they raise several broods throughout the season. Summer’s really not so bad in Arizona, particularly weighed against our terrific winter weather. Luckily most of us make good use of that terrific human adaptation called air-conditioning.


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