Wild Side: Masters of Camoflage
Eastern gray tree frogs are common around our place. We see them stuck to the front windows of our house on damp mornings. Their toe pads allow them to cling to vertical surfaces. They make resonant trilling calls on humid days long after their breeding season in the spring.
Gray tree frogs are masters of camouflage. They can change color from gray to green with dark mottling, to mostly green on the background color of their habitat. The inch-and-a-half-long frogs are a tasty snack to many predators. Their camouflage is a life-saver for them and probably allows them to be unseen until they ambush their insect prey.
The combination of bumpy skin and three layers of chromatophore cells provide actively changing camouflage with melanophores containing dark brown melanin, iridescent iridiphores that reflect blue light, and xanthophores with yellow pigments. Gray tree frogs can change color to match their background habitat or their mood within seconds. They expand or contract the dark and light chromatophores and even by changing the shape of the cells. Some other animals, like chameleons, flounders, octopi and reef squids can also perform this amazing feat of actively changing camouflage.
Many animal species use fixed patterns of camouflage. Northern leopard frogs aren’t common here but we occasionally see them zipping through the grass. I keep a lookout for leopard frogs when mowing. I don’t mind a delay to let them leap to safety. They are hard to spot when they stop. Leopard frogs have a green-brown background color with rounded brown spots bordered by yellow. Their undersides are creamy white.
A smooth green snake surprised me in the raspberry patch recently. I only saw it when it moved. Its emerald green color and smooth scales mimic a plant stem. Another small snake that’s fairly common here is the red-bellied snake. With a steel gray back, it’s hard to spot on the ground among sticks in the woods. The underside, however, is bright red-orange edged with blue-black. We occasionally see them basking in the sun on our gravel driveway.
Nighthawks fly over our valley in the evening in graceful loops chasing insects. We call them “buzz birds” because of their call. They are easy to identify in flight by their pointed wings with white patches near the bend of the wings. They are so well camouflaged that they don’t build a nest. I’ve never seen one on the ground. We have seen whippoorwills (in the same family as nighthawks) on the ground but they led us to them by their loud calls.
Ruffed grouse have excellent camouflage with gray or reddish brown mottled feathers that conceal them well when they are still. When hunting, I look for them moving, listen for their clucking, or look for small football silhouettes perched in the trees. It helps to see them first before they take off in an explosive flurry of wings.
I wear camouflaged clothing when trout fishing and when hunting waterfowl and turkeys. My camouflage clothing has crude imitations of forest or marsh patterns. We can’t expect to have camouflage that adapts to the background as well as the animal masters of camouflage.
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--Dan Wilcox, outdoor columnist