HAVE MANY WAYS TO PROTECT THEMSELVES
back, running away and hiding are three instinctive responses if a person
feels threatened. Many animal species do likewise, and some have their
strategies honed to perfection.
combination of escaping death or injury by leaving the danger zone followed
by concealment is practiced by Cope';s gray treefrog, a species found
throughout most of the eastern United States. Many people have heard
the musical trills of these little vocalists as they call from trees
on summer nights. But in daylight you could walk right past one sitting
on the trunk of an oak tree. If the frog doesn't move, chances are you
will not see it because of its amazing camouflage. It looks like gray
have no qualms about eating small frogs, so how does this seemingly
defenseless creature escape if it is moving around and gets spotted
by a hungry bird? Step one for the frog is a big one. It jumps toward
another tree. While in the air, it spreads out its hindlegs, revealing
a bright yellow blotch on the back of each thigh. The bird meanwhile
is making its move, presumably focused on the fast-moving yellow target.
But when the gray treefrog lands on a gray-barked tree and pulls its
feet up alongside its body, to the eye of the bird, the yellow morsel
of food has disappeared. The gray treefrog sits still, relying on its
remarkable camouflage against the tree. The hapless bird is still looking
for something bright yellow.
is known as flash coloration, wherein a prey animal exposes an obvious
and colorful part of its body and then conceals it, allowing the animal
to blend in with its background. If the acrobatics, misdirection and
camouflage do not work for a Cope's gray treefrog, it has one last trick
up its sleeve. In a sense these treefrogs fight back: They are poisonous
to touch. They don't bite, but the secretions on their skin are extremely
noxious and can be transferred from the frog to the eyes, mouth or lining
of the nose of someone who picks one up. It once took me two painful
hours before I could open my eyes and see again after capturing a gray
treefrog in a swamp. After handling it I foolishly rubbed my eyes. A
predator catching a gray treefrog would have a not-so-tasty meal to
is another common way humans deal with a menacing adversary. And so
do some animals. I recently heard a rabbit scream when I went out to
get the newspaper before daylight. This troubling sound is reminiscent
of a wailing child and will definitely give one pause when standing
in the driveway in the dark. I can only imagine the chill bumps had
I been deep in the woods. Some frogs are known to give a loud, similar-sounding
distress call when being attacked by a predator, often a snake. Screaming
by a bullfrog can be evoked on rare occasions by a person catching one.
I have observed this behavior once and assure you that an open-mouthed,
shrieking bullfrog is disquieting.
for this behavior is the predator attraction hypothesis. The sequence
has been confirmed in one case I know of. A snake grabbed a frog as
prey; the frog screamed; a hawk heard the scream and headed for the
scene of the crime. The hawk captured the snake, which was occupied
with the frog and also was a bigger meal. Meanwhile, the snake released
the frog and turned its attention to its attacker. Of course, the hawk
might have eaten the frog, but its odds of escaping had definitely increased.
a bobcat or coyote hearing a screaming rabbit in the woods might head
toward the sound with expectation of some kind of meal and inadvertently
disrupt the attack against the rabbit. I, meanwhile, would be headed
in the other direction at the sound of a shrieking rabbit.
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