By Esther Rubin
Day after day of 110 degree temperatures. You can feel the heat radiating up from the sand by 10 a.m. To the human eye, there appears to be no shade, no haven from the sun’s brutal rays. How does anything survive out here?
But things do. And quite cleverly. The plants and animals of the desert have some of the most astonishingly effective strategies for surviving in one of Earth’s most extreme climates, the great Sonoran Desert.
Summer survival strategies of desert-dwelling plants and animals:
Don’t Drink the Water
- Bighorn sheep can obtain moisture from barrel cactus. They use their horns to smash the spiny exterior of the cactus and eat the moist pulp on the inside.
- The kangaroo rat survives without drinking standing water. It obtains adequate water from its diet of dry seeds. To reduce water loss, they have no sweat glands and produce urine that is twice as concentrated as seawater and feces that are 5 times drier than a lab rat’s droppings!
- Many succulent plants have extensive roots near the desert's surface to obtain and quickly store water when it is available. For example, the roots of a 2-foot tall cholla cactus may be up to 9 feet long.
- Since plants lose valuable water through the pores on their leaves, most succulents don’t have many leaves, and some have no leaves at all.
- Vultures use evaporative cooling to deal with the heat. On hot days they will urinate on their own legs.
Avoid the Heat
- The nocturnal Merriam’s kangaroo rat may spend less than one hour on the surface per night.
- The spadefoot toad digs burrows up to 3 feet deep and may spend as much as 10 months of the year underground.
- The antelope ground squirrel holds its bush tail over its back like a small sun parasol.
Stay off — or under — the Hot Sand!
- The sidewinder snake has a unique means of locomotion, reducing its contact with the hot sand.
- Fringe-toed lizards have elongated scales on the toes of their back feet, which give them added traction for quickly moving across sand dunes. Their heads are shaped so they can dive into the dunes without much resistance and “swim” in the sand when threatened by predators. Once under the sand, their noses are adapted to allow them to breathe without getting sand in their lungs. And their ears are protected by fringes that keep sand from entering their ears (they could have been called “fringe-eared” lizards instead).
Adapt to Extremes
- Desert pupfish (yes, there are fish in the desert!) are among the most heat tolerant of all fish — they are known to survive in water temperatures of 112°F. They are also very salt tolerant and can live in water 2-3 times saltier than seawater.
- Fairy shrimp are a type of aquatic invertebrate that live in desert dry lakes or “playas.” They can remain in a state of suspended development for months during extended dry periods, in the form of cysts. When the playas fill with water, the fairy shrimp develop, mature, and breed during a short period.
- Many desert plants, like the beautiful ocotillo, can cope with long periods of drought by dropping leaves and going into a period of dormancy. They look dead, but they are perfectly fine — just waiting for the next rains.