Northern Leopard Frogs
Leopard frog. These guys are sometimes brown
With the coming of summer we have a chance to appreciate our amphibians more. Maine, in case you haven’t noticed, is sort of a cool state and does not have a high diversity of frogs and toads. We have 9 species of frogs and toads, and, listed in the approximate order that they serenade us in the spring, are: Wood frog, Spring Peeper, American toad, Northern Leopard frog, Pickerel frog, Gray treefrog, Bullfrog, Green frog and Mink frog. We have all of these species in the Quoddy region, although they are not very evenly distributed. For example, here on Leighton Point in Pembroke I have only seen and heard the Wood frog, Spring Peeper, American toad, Gray treefrog and Green frog. All of the other frogs seem to be further inland, and I’m not sure why. The Northern Leopard and Pickerel frog do seem to prefer their home turf and are certainly not as freeze tolerant as Wood frogs, but they like damp meadows, and we have lots of those down here. Bullfrogs are supposed to be aggressive colonizers and supposedly can even tolerate pretty brackish water, but I have seen nothing of them down here. Such are the mysteries of nature.
The Leopard frog Rana pipiens and Pickerel frog Rana palustris are our only brown spotted frogs and they can be confused. These frogs are of the same genus, and hybrids have been reported, but none that I know of in Maine. The spots of the Leopard frog are smaller and rounder than the spots on the Pickerel frog, and often the Leopard frog is green with brown spots. Both frogs may be found in the similar habitats. They both require ponds for spawning, and this is occurring about now. They both have a call that is described like a ‘snoring grunt’ and they may even call from underwater. After mating, the adults of both species generally leave the ponds and like to forage in damp meadows and woodlands until the cold weather arrives. The Leopard frog may be a little bigger at 4 inches maximum, and I consider it a better jumper than the Pickerel frog. If I were to enter a frog jumping contest I would certainly opt for a Leopard frog. I’ve never been to a frog jumping contest, but from what I’ve noted the contestants generally seem to have a large something like a fat bullfrog. I would put up a sleek Leopard frog anytime against a bullfrog.
Although the Northern Leopard frog has been used sparingly in culinary creations, its major contribution to people has been its use as a laboratory test animal, especially for neurological studies. Over harvesting and habitat destruction has severely limited its availability in the wild, and some laboratories have questioned the advisability of obtaining them from dealers in regards to similarity. They are for sale on the web from such places as Connecticut Valley Biological Supply for $8.50 each and Maine DIFW has listed the Northern Leopard frog as a Species of Special Concern.
Besides Leighton Point it apparently is very uncommon in the south coastal zone of Maine. In the western part of its range towards the Rocky Mountains the Northern Leopard frog seems to be subjected to maladies that result in many deformed individuals. Pesticides and other environmental problems are the suspected culprits. I have not witnessed those problems here in Maine, but there seems to be a move to change the scientific name and classification of the Northern Leopard frog to Lithobate pipiens. Aw man! I barely got familiar with Rana pipiens.
Pickerel frog
