Rare Blue Leopard Frog Found in Massachusetts

A rare blue leopard frog, a species so vibrant and beautiful it looks like it "belongs in the tropics," was recently found in Massachusetts of all places.

Leopard frogs, which are named for their dark spots, are usually green, beige, or a combination of the two; so when Jacob Kubel, a conservation scientist with the state Division of Fisheries and Wildlife's Natural Heritage and Endangered Species Program, stumbled upon the jumping blue blur in Sudbury wetlands this past summer, he didn't realize at first what he was looking at.

"I couldn't be sure of the exact color," Kubel told The Boston Globe, "so I just thought to myself, 'Oh, I have a brightly colored one here - he should be easier to chase down.'"

It's typical that individuals of wildlife species vary greatly from one another, but upon closer inspection Kubel realized that the two-inch frog was "truly blue, without a hint of green" - a rarely seen blue leopard frog.

This one-of-a-kind amphibian has only been reported three times before: once in New Jersey in 2003, once in Delaware in 2007, and one in New York earlier this year. Blue leopards are so unique, they account for just one in 300,000 specimens.

Sometimes green and bull frogs, two other species found in Massachusetts, tend to be blue or partly blue, but blue leopard frogs are entirely different. Their unique coloring stems from the lack of a yellow pigment typically found in their skin cells. During embryonic development, the pigment cells either don't develop or do so in another part of the body other than the frog's neural crest.

Leopard frogs in general were once the most abundant and widespread frog species in North America, according to National Geographic. But starting in the early 1970s, their numbers dropped drastically, and scientists still don't know why. They cite pollution, deforestation, and water acidity as possible factors.

With so many less leopard frogs hopping around, it's a wonder Kubel managed to discover a rare blue leopard frog in Massachusetts. He and other scientists are now catching leopard frogs and extracting their DNA - a harmless procedure - to determine whether they are members of this still unnamed species.

"In the big picture,'' Kubel told The Globe, "amphibian populations are important to research, monitor, and understand because they are critical components of the food web and are relatively sensitive to environmental change.