HOT AND WILD: NATURE'S SEASONAL SURVIVAL TECHNIQUES

By Plateau Land & Wildlife Management

Dashing from air-conditioned home to air-conditioned car, slathered in sunscreen, ice cold bottle of water in hand, Texas summers are almost survivable. While the first official day of summer arrived June 21, we received a blistering hot preview of the change in seasons starting in May. Some parts of Texas set record temperature highs over a month ago, and the state is in the worst drought in 44 years. Not that any of us need reminding. But while Homo sapiens is fortunate to have many methods (some of which are quite artificial) of coping with summer conditions, other members of the animal kingdom aren't as lucky. How does our Texas wildlife deal with these hot, dry living environments?

Despite harsh conditions, semi-arid and arid regions of Texas (including portions of Central, most of South, and all of West Texas) are able to support a wide variety of fauna. Survival strategies can include behavioral techniques or biological adaptations. Regardless, life in inhospitable environments often comes down to maintaining body temperatures and acquiring and retaining water.

One basic behavioral technique is to seek shelter from the conditions. While we crank the A/C and ceiling fans, small mammals, insects, and reptiles spend the warm hours of the day in underground dens, burrows, rock crevasses, or brush piles. These daytime hideouts are many degrees cooler than exposed areas. Because their skin is porous, frogs are at a high risk of dehydration. The moist habitats needed by frogs aren't always available - on the surface at least. During droughts, frogs will spend most of the year buried in cool, moist conditions well underground where they can absorb water through their skins. During this process, called aestivation, metabolic rates can be lowered as much as 90%.

Nocturnal (being active at night) behavior is one very effective and common way of avoiding the heat. Bat departures at dusk are the beginning of a night full of feeding activity. Snakes, skunks and opossums are examples of native animals with nocturnal behavior. To nature lovers made uncomfortable at the sight of snakes, be thankful!

Texas horned lizards, known locally as horny toads, use a behavior during summer rain events known as "rain-harvesting." These reptiles will lower their heads and arch their backs high in the air during precipitation events. During small rain events, most of the rain hitting the ground dissipates into the dry ground very quickly. However, moisture falling on the horned lizard is caught on its backs and drawn toward its head through very small channels between its scales. Instead of seeking standing water, the Texas horned lizard can simply open its mouth to drink.

Black and Turkey Vultures, both very common in Texas, use a more unsavory technique called urohydrosis to maintain body heat. These birds will excrete urine on their bare legs. Evaporation of the urine cools these areas and the cooled blood is then circulated in the body. Two additional coping methods used by vultures include spending daytime hours in flight at high altitudes where temperatures are much cooler and acquiring moisture through the carrion they consume.

The bodies of many animals have evolved in certain ways to deal with harsh conditions. Jackrabbits dissipate heat through their extremely large ears containing many blood vessels. In fact, jackrabbits occurring in more southern areas have larger ears than others occurring in cooler areas.

One widespread adaptation is for warm-blooded, wide-ranging animals occurring in warmer environments to be smaller in size than their counterparts occurring in cooler environment. Within a species, body mass tends to increase with latitude and colder climates. This pattern, known as Bergmann's rule, is based on heat conservation. Smaller body size is selected in warmer environments because smaller bodies have higher surface area to mass ratios, thus allowing for the more effective dissipation in heat. For example, body sizes of white-tailed deer in Texas are much smaller than those occurring in Canada.

The next time you get geared up for a hot day of bumming around at the beach, floating the Frio, or getting some work done on your property, take a second to think about nature's critters. While you won't see deer bedding down in air-conditioning or turkeys sporting cowboy hats anytime soon, know that Texas wildlife are built to survive.

From our customized Wildlife Management Plans to convert your land from an Ag Tax Valuation or Timber Valuation to Wildlife Tax Valuation, to our range of environmentally and financially smart services and products, Plateau Land & Wildlife Management is dedicated to increasing your enjoyment of your land, and helping you achieve your ultimate land vision.