American Bullfrogs Taking Over Yellowstone River

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Both Three Dog Night and Creedence Clearwater Revival in their song and cover “Joy To The World,” told us that “Jeremiah was a bullfrog,” but they surely can’t all be named Jeremiah can they? Especially when we are talking about millions and millions moving into areas that they were never seen before and breeding prodigiously. The American Bullfrog, while native to the east coast now exists in every state with the exception of North Dakota. The spread westward may or may not have to do with the Everglades in Florida playing host to a number of Burmese pythons and other exotic creatures that would love to snack on the bullfrog.

Bullfrogs: The worldwide scourge

The species was never found in Montana prior to 1999, but then “Bullfrogs were likely introduced to the Yellowstone River region for food, recreational hunting, bait and pest control, and as released pets,” according to USGS scientist Adam Sepulveda, of the Northern Rocky Mountain Science Center in Bozeman, Montana.

Worldwide, the bullfrog has been blamed for the decline of native amphibian and reptile species. Conservationists in Montana worry about what these things, that eat anything, will eat as well as their propensity for spreading disease.

“The impacts of bullfrogs on native amphibians in the Yellowstone River are not yet known, but native Northern leopard frogs are likely to be most vulnerable to bullfrog invasion and spread because their habitats overlap,” Sepulveda said.

In 2010, Sepulveda and his team found bullfrogs occupying 37 miles of the Yellowstone river. In just three years’ time that has grown to 66 miles of river and it could have spread much further if not for the wealth of tasty snacks both in and around the river.

Won’t be easy to contain

These things are in for the long haul and will be difficult to contain, much less eradicated,  given the interconnected ponds, side channels, backwaters and canals of the Yellowstone system.

“They are going to eat anything they can fit into their mounts. It doesn’t matter if it’s another frog or a bird or a mosquito,” said Sepulveda, who co-authored a study on Yellowstone River bullfrogs appearing in the journal Aquatic Invasions.

While few will lose any sleep about the willingness of the bullfrog to go after mosquitoes, it’s the other animal life that bothers Sepulveda and others.

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