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Come back to this page each day to read another entry from Cathie Katz's beautifully illustrated journal, "Nature a Day at a Time."
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Leopard frogs (Rana) are one of the most widely distributed amphibians in the U. S. Green and brown spots on either side of light ridges running down their backs camouflage them well in the vegetation of marshes, ponds, streams, and woods. During mating season, the colors of many frogs change. Pigment cells under their transparent skin deepens or brightens to get the attention of the opposite sex. The level of melatonin, a hormone that affects skin pigmentation, drops as daylight hours increase in the spring. Sex organs function again after a winter of darkness when melatonin levels were high. Biological urges originating in the pineal glands in humans is often light-driven and correspond with melatonin levels. Who knows how much human behavior is determined by seasonal light when ancient urges are triggered by more or less light?
... a curious thing about these frogs is that they stray so far from water, much farther than most other frogs, which are practically aquatic animals. Maybe the leopard frog represents the advance guard of frog evolution, separating itself from water more than its cousins, preparing for a fully terrestrial life.Castle Freeman, Jr. in Spring Snow |
Cathie Katz, the author of several books on natural history, also co-founded The Drifting Seed, an international newsletter about rain forest drift seeds. In her engaging Nature a Day at a Time, published by Sierra Club Books and Random House, Katz interweaves fascinating facts about familiar creatures, pen-and-ink drawings and quotations.
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