This month’s Big Word of the Month is not really that big. You can probably figure out what it means even if you have never heard it used.
A microclimate is simply a small area that has different temperature and/or moisture conditions than the surrounding area. Many factors can contribute to microclimatic conditions within an organism’s habitat. For instance, south-facing hillsides (in the northern hemisphere) receive more solar radiation than nearby north-facing slopes. Therefore, southern exposures tend to be warmer and drier.
We all know that the shade of large trees is a nice place to be on a summer day. Much of the incoming solar radiation is absorbed or reflected by the leaves of the canopy, which can keep the ground beneath several degrees cooler. The process of transpiration also helps cool wooded habitats but I won’t introduce another big word this month!
I recently used a hand-held IR thermometer to measure temperatures around the museum grounds on a hot day. As I strolled down the boardwalk towards Catch the Wind the air temperature was about 91°. However, in the shady and damp corner behind the wolf exhibit it was only 78°. I didn’t go into the wolf exhibit that day but I bet the temperature in the den was even cooler since it is covered with several inches of soil.
I walked over to the lemur exhibit and found the surface of a large log had already reached 95° since the sun was shining on it. However, a few feet away under some large boulders on the moist ground, conditions were much nicer at a chilly 72°. So the next time you see ringtail lemurs under those rocks you will know they are not camera shy but rather wondering why you are standing out in the hot sun.
The coolest spot I measured that day was in the farmyard in the small nook where I found Nimbus the rabbit. She was cooling it between two bottles of ice water where the temperature was 68°! Her ice bottles and fan are a good examples of how we try to help our animals deal with summer heat. Keeper Marilyn discussed some of the other techniques we use to keep our critters safe and cool.
In the wild animals often take advantage of microclimates to aid their survival. A little bit of shade can be a matter of life or death for a desert organism with limited access to water. On a cold spring morning, a sunny rock can help a snake get its body temperature up into an optimal physiological range.