Scientists are reporting an invasion of hungry American bullfrogs along the Yellowstone River in the US state of Montana.
The bullfrogs are said to eat nearly anything, including other bullfrogs, and pose a threat to native species.
The number of the animal’s breeding sites has nearly quadrupled since 2010.
Efforts by state and federal agencies to contain the spread of the animals has so far failed, after their numbers proved too great to control.
“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,” US Geological Survey biologist Adam Sepulveda told the Associated Press news agency.