Imagine that you are about the size of a Reese’s cup, and to many animals, equally delicious. Your place in the food web lies somewhere near the middle, part predator, part prey. You dine on insects, slugs, snails, and even the occasional small bird. You are a northern leopard frog (Lithobates pipiens) and dangers abound. Predators lurking above include herons, hawks, and waterfowl. On the other side of a stump, raccoons, foxes, and snakes await your misstep. Water, your true home, swarms with otter, mink, and bullfrogs anticipating a particular main course. How do you survive such an onslaught?
Many of us may think that we witness a frog’s primary defense as it jumps away. But his erratic hopping demonstrates his last-ditch effort to stay alive. Before he leaps for his life, stillness keeps him hidden among the leaves; camouflage is his best friend. Numerous amphibians employ camouflage to protect them from potential predators, but few excel in this department as well as the northern leopard frog.
The waning months of summer in Vermont bring about new dangers for these cryptic croakers, as they venture from the water’s edge into meadows to forage for food. Luckily, hues of green or brown and rounded black spots decorate their skin. These colors blend in inconspicuously to the fields of forbs, grasses, and goldenrods in a cloak of camouflage called background matching. Types of deception abound in the animal kingdom. Think of the challenge of spotting a white-tailed deer fawn (Odocoileus virginianus) resting on the forest floor, an eastern screech owl (Megascops asio) waiting motionless in the hollow of a tree, or a spring peeper (Pseudacris crucifer) hiding among the autumn leaves, and you have background matching. Whether feather, fur or frog, these animals blend in beautifully with their environment.
With the warmer portion of fall still upon us, spend a Saturday in the meadows of the Champlain Valley and try to catch a glimpse of a leopard frog during its feeding forays. Vermont winters hit hard for these amphibians. However, leopard frogs have a trick up their sleeves that they share with the northern map turtles (Graptemys geographica). Both of these cold-blooded critters head to well-oxygenated waters to escape the brutal winter winds and hunker down into hibernation. They begin to tuck themselves in by late October to early November, and won’t fully emerge until February or March. By then, it will be time to fatten up, find a mate, and blend into their surroundings once more.