Wisconsin Sea Grant Frogs: Field Guide
Copes Gray Treefrog
Call: A fast, harsh, buzzing trill usually lasting
less than a second
Size: 3-6 cm in length (1.2-2.4 inches)
This frog has considerable color-changing ability; the same frog can vary
in color from light gray to brown to pale green; one or more dark irregular
blotches, sometimes outlined in black, may be visible on the back; a dark
stripe or band often slants from the back of the eye to the front leg;
belly is white, and there is a patch of bright yellow or orange under
the hind legs
Favoring grasslands and savannas, these frogs also utilize farm woodlots,
swamps, old fields, and suburban yards -- almost anywhere where breeding
ponds are near trees or shrubs; most common throughout the western and
southern portions of the Great Lakes region.
This frog is virtually identical to the Eastern Gray Treefrog, though
the Eastern Gray Treefrog tends to be slightly larger and bumpier-skinned.
The calls differ, however, and Eastern Gray Treefrogs have twice as many
chromosomes as Cope's Gray Treefrogs.
Breeding: Early May to late June
FACT: Both the Cope's Gray Treefrog and the Eastern Gray Treefrog
are most active at night, when they look for food in low shrubbery or
in trees. They are talented climbers, and may scale trees to heights of
30 feet or more above the ground! A special mucus
produced on their toes gives them an extra-sticky cling and helps them
climb even smooth surfaces.
Did you know?
Gray Treefrogs cope with cold temperatures in an unusual
way -- they literally freeze!
Experiments have shown that Gray Treefrogs can survive temperatures
as low as -6 C (21 F) for several days, when more than 40% of their body
fluids may be completely frozen.
They accomplish this by producing large amounts of glycerol
in their blood and body tissues, which acts as a natural "antifreeze"
to prevent ice from forming inside their cells.
copyright 2001 University
of Wisconsin Sea Grant Institute