How animals keep cool

As the dog days of summer arrive and it's hot and humid outside, we can usually escape to air conditioning or to a shady area, wear light, loose-fitting clothing and drink plenty of fluids to find some comfort from the oppressive conditions.

What do wild animals do when it gets hot outside?

Animal adaptations to hot weather revolve around behavioral and physical adaptations.

One common behavioral adaptation involves changing activity patterns to avoid the heat of the day by being most active in the early morning or evening hours.

Have you noticed how quiet it is during the heat of the day when compared with the sounds of the early morning or nighttime? In the tropics and desert, a number of animals go into a summer hibernation, called aestivation, to lower their metabolic rate and conserve water.

Some animals and reptiles burrow deep into the ground to find cool resting places. Birds can travel to milder areas or find cooler air currents in which to glide. Animals will use water to cool themselves either by splashing around in a water hole, covering themselves in mud or, as vultures do, urinating on their legs.

Many animals cool themselves by panting or sweating. Dogs dissipate heat from their mouths by panting or sweating from their paws. Many birds fly with their mouths open in the summer months to cool themselves. Domestic and wild cats lick themselves to cool down.

There are also a number of physiological adaptations animals have to help dissipate heat and conserve water.

A common adaptation is the changing of a fur coat from a thick and darker coloration in the winter to a less dense and lighter color in the summer. Many summer fur coats are thick on the top and very sparse on the underside; this helps conserve water and increase airflow around the vital organs.

Elephants have the ability to tighten and loosen their blood vessels to force heat out of their bodies through their mouth, and their very large ears flap constantly to help dissipate water and cool themselves. Reptiles have thick, scaly skin that prevents water loss. Many desert animals have adaptations in their kidneys that allow them to conserve water so they do not have to drink very often.

Most of our cute family pets don't have to adapt; they are pampered with air conditioning on hot days.

Signs that fall is coming

Despite the heat we have been experiencing, there are many signs that autumn is on its way. There has been a gradual change of early-season herbaceous plants to those that grow in the late summer and stay around for fall. Many plants, such as goldenrod, Queen Anne's lace, ragweed, cardinal flower and chicory, are now present and will hang around until the killing frosts arrive later this year.

Hold on -- cooler weather is coming!

Nature Notes for 8/14/2011