WASHINGTON – When August heat rises, people and animals reduce outdoor strolling or scurrying to stay cool. While most humans have air conditioning to ease discomfort, though, nature’s other creatures need to cope.
Many warmblooded animals use some of the same techniques to reduce overheating that we do: They stay in during the hotter part of the day. Most cannot sweat as we do, but they find other ways to evaporate water off their bodies, which cools them. They wear lighter clothing, as in fur or feathers.
This is why you do not hear many birds singing at noon. They come out of the trees and bushes at dawn to feed and chat, then retreat into the leaves until it cools off toward evening. In the tropics, birds that live at the top of the trees often move during the day deep into the foliage, where the temperature can be substantially lower, said Russell Greenberg, director of the Smithsonian Migratory Bird Center, who says birds doubtless do that here, too.
Panting is one alternative to sweating for dogs, cats, many other animals and birds because it runs air over moist breathing parts, which promotes evaporation. Pelicans can even enlarge their throat sacs to make more area available for evaporation. Perhaps the most disgusting bird practice – to us, anyway – is that of storks and turkey vultures, which defecate on their legs as a way of cooling down.
Birds also can flutter their throats, which pushes heat out. So does opening their wings, which also exposes their more lightly feathered underwings from which heat can escape.
Squirrels, groundhogs and other mammals also often forage at dawn and dusk. They have lighter fur in summer. And some have adapted to our ways: Alonso Abugattas, a naturalist at the Long Branch Nature Center in Arlington, Va., says he’s heard of squirrels that stretch out on people’s porches to be near the air conditioning leaking out the door.
Escaping the heat is another cooling technique. Dragonflies go into what’s called the “obelisk position,” pointing their bodies upward rather than outward to minimize sun exposure. When streams or creeks heat up too much, insects living there dig down into the rocks and go into a summertime hibernation called estivation.
“A number of salamanders – the mole salamander, marbled and spotted – are pretty subterranean most of the time, but also the red-backed, the smaller one that most people are familiar with, will find cavities or places to go down into,” said Cliff Fairweather, a naturalist with the Audubon Naturalist Society. “Whereas a log you might turn in the fall or spring and find a red-backed salamander under, in the hot part of the summer you won’t.”
Snakes, turtles, lizards and other coldblooded animals do not have this range of options because they do not control their temperature. They need the sun for energy, but even they can get too much of a good thing and need to avoid overheating.
So snails use their mucus to paste themselves to a leaf or the side of a wall, which prevents them from losing too much moisture. A box turtle scoops out a small bit of dirt, digging in to cover its lower shell, then closes up and rests for days in the cool, moist earth.
Tree frogs, according to Fairweather, can change their color a little bit, turning darker when they want to absorb more sun and lighter when they need to hide from the rays. It’s not unlike our practice of wearing white clothing when it’s hottest out.
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