With fall hitting us like a lighting bolt, it feels like we’re closer to winter than the summer we’ve just left behind. Amphibians and reptiles of all kinds are becoming increasingly scarce. I was quite surprised to find this gray tree frog near the bottom of a tree.
Yes, just last week I could hear these frogs singing at the top of their trees. However the weekend brought rain and cold weather. My first impression, they are preparing to hibernate. That’s when I asked myself, what are the specific characteristics of the gray tree frog’s winter hibernation.
My belief was that they will take refuge in an underground burrow to protect themselves from frost through their winter hibernation. Although it can choose to do so as a form of protection from predators, the Gray tree frog has a high freezing tolerance. They can survive freezing on up to 80% of the mass of their body for the duration of the winter hibernation. Once thawed out in spring, they come back in great shape with no ill effects. The Gray tree frogs are protected by antifreeze in their system. It prevents the water in their bodies from freezing solid. This prevents frost damage to organs and other vital body parts. When they are frozen, their lungs, heart and other organs stop functioning. The brain activity of the gray tree frog becomes almost nonexistent.
As for the photos, the task was as difficult as finding these well camouflaged small frogs in the obscurity of the forest. (A big thank you to M.C. for the eagle eyes) I had no adequate means of artificial lighting for the task, so the images are taken in natural light. I used a reflector to try and clear up some shadows. Fortunately the Gray tree frog was frozen still from the colder temperatures. The photographs are taken at 100 and 200 ISO for a period of 8 to 20 seconds with an aperture of f/27 to f/38. The camera used is a Nikon D810 with a Nikkor 105mm Micro lens. All mounted on a Manfrotto 055XPROB tripod.