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Posts tagged “Animal Adaptations

Porcupine Foot Pads

Given the amount of time porcupines spend in trees, it’s not surprising to see that their feet are well adapted for climbing.  Long, curved nails that grip the bark, as well as “pebbly” foot pads designed to prevent slipping allow this prickly rodent to climb just about anywhere it wants to.  (Hind foot pictured.)


Cryptic Coloration

Can you find the brown creeper that’s on the trunk of this black cherry tree? This is cryptic coloration, a form of camouflage in which an animal blends into its environment, at its finest.  A forager of insects and spiders tucked away behind and in the crevices of bark, the brown creeper starts its search at the base of a tree, climbing upward and often spiraling around the trunk until it nears the top.  It then flies to the base of a nearby tree to begin the process again. As W.M.Tyler wrote in 1948 in Bent’s Life Histories of N.A. Birds, “The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the law of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind.”  


Beaver Scent Mound

 Beavers, like many mammals, communicate with chemical signals.  In scent marking, beavers actually build a mound of mud on which to place their scent. First they dive down to the bottom of their pond, dig up an armful of mud with their front feet and swim to shore with the mud held against their chest.  Walking on to the shore on its two front legs, the beaver deposits this mud next to the water.  Beaver scent mounds can be quite small, or as high as three feet or more, depending on how many loads of mud they contain. The beaver straddles this pile of mud and applies castoreum from its castor glands, or anal gland secretions, or both.  The purpose of building a mound is to elevate the odor (helps with scent dispersal), to intensify the odor by putting it on a moist substrate, and to protect it from flooding when the pond level fluctuates.  Beavers build most of their scent mounds in the spring, when young beavers are dispersing and claiming new ponds, but I have found several fresh ones this fall, including the one in the photograph. (Click on photo to enlarge.)