4 Animals Built to Beat the Heat
#EcoList of Things We Love
Summer’s upon us, and while in temperate climes that means it’s time to break out the lemonade stands, joyfully leap through sprinkler arcs and inhale the scent of fresh-cut grass, we desert dwellers pretty much hibernate. At least, we hunker down and get fatter. The hardy among us limit ourselves to ceiling fans and evaporative coolers, the occasional sweat-soaked siesta and maybe an ice-cold brew. The wimpier among us treat ourselves to copious, self-indulgent air conditioning, while the straight-up rich migrate to the Colorado peaks or take cruises to the Antarctic. Outside the human realm, though, there are legions of critters remarkably adapted to survive the extremes of the season. Here’s a very small sample.
Harris Antelope Squirrel
These cute natives of the U.S. Southwest dash around on the desert sands in the middle of the day, for all the world as though they enjoy it. Tiny, ground-dwelling rodents that look like chipmunks, Ammospermophilus harrisii hide in their burrows when they need to and use their puffy tails as built-in parasols.
But their slickest trick is self-flattening, and it’s excellent to watch. These squirrels spread their bodies out as flat as they can in the shade — and that’s very, very flat. They basically make themselves into living rugs. This allows heat to radiate out quickly through their bellies, where their pelt of fur is thinnest.
Like all insects bees are “cold-blooded,” though that doesn’t actually mean their blood is cold. (Truer to say the blood temperature of ectothermic animals tends to be about the same as the surrounding temperature.) Point is, these members of the genus Apis have cleverly devised mechanical ways to regulate their microclimate. Female worker honeybees are the air conditioners of their society. When temps in the hive are too high for the baby bee brood developing inside wax cells, the female workers transport water to the hive and fan it so that it evaporates faster, bringing the temperature down.
Conversely, when the temperature drops too low — because honeybees tend to want to keep their young between about 90 and 95 degrees Fahrenheit — they contract and relax the muscles they use to fly with without beating their wings, decoupling those wings from the muscles. The vibration of that movement produces heat.
Living nowhere on Earth save a single hot spring in Chihuahua, northern Mexico, this highly imperiled pupfish — one of a number of pupfish species that are adapted to minuscule, isolated pockets of water in arid parts of North America — has been called “the world’s hottest fish.”
That’s because these tiny dudes, whose Latin name is Cyprinodon julimes, swim around in water as hot as 118 degrees Fahrenheit without batting an eyelash. Scientists believe they’ve adapted to their heating-up waterworld by means of what they loftily call “physiological plasticity” — which in this case is expressed in the animals’ breathing. Pupfish can go five hours without inhaling oxygen through their gills. Inhaling oxygen and breaking it down generates energy for living creatures, but also, at high temperatures, produces a bunch of “free radicals”— and we’re not talking about sexually liberated hippies. These are chemicals that can be harmful, so pupfish cope by switching out aerobic respiration with anaerobic, in which they generate ethanol. It’s a tough process, with its own health hazards, but it seems to help them survive where most of us could not.
Scincus scincus is a beautiful, yellow and brown skink, of a six-or-seven-species genus that ranges across north Africa and parts of Asia, from Algeria to Pakistan. This lizard is colloquially called a “sandfish” because it basically swims through the sand: It can move entirely underneath the desert sands, out of range of the perishing sun, without needing a tunnel. It propels itself along in a kind of sand-immersed undulating motion, not using its limbs as paddles but rather keeping them tucked in close to its body — and its movement is extraordinarily efficient. Its pointy snout helps it push through the sand grains, and its super-tough yet gorgeous skin lets it cruise smoothly.
Perhaps best of all, transparent windows in its eyelid scales allow it to keep its eyes open as it plows through the earth, much like high-tech Olympic goggles.
And One Animal That Isn’t Built to Beat the Heat: Pug Dog
There’s one animal that starts to melt — first psychically, then actually — when the thermometer hits a mere 75 to 85 degrees Fahrenheit: the mighty pug. These smush-faced companions of ancient Chinese emperors now number among Instagram’s best-loved animal celebrities. But intrepid they are not. Your average pug doesn’t like to be in overwarm temps for more than 15 minutes running. They have tiny air passages in their short noses, as is plainly visible to the naked eye, and as a result they can’t expel heat efficiently. They quickly start to huff and puff, and indeed may succumb to heat exhaustion, if you don’t rush them back into a cool boudoir very promptly.
As a pug owner myself, I’m not making light of this — pug overheating is serious business. I’d counsel strongly against tropical pug ziplining, pug beach volleyball and pug safaris. Your pug may yearn for these adventures, but sometimes a pug doesn’t know best. Avoid the Sahara, the Serengeti and the Amazon with extreme prejudice. Keep those pugs safely on your laps.
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