Some Catfish Are Eating A Large Amount of Mice, Study Finds

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Catfish are named for the long, wispy barbels that jut from their faces like a cat’s whiskers—not for their catlike behavior. But it turns out some catfish may share more than looks with their mammalian namesake: According to a recent study, lesser salmon catfish love gobbling up mice, just like cats.

New Scientist reports that scientists from Western Australia’s Murdoch University studied the stomach contents of lesser salmon catfish (Neoarius graeffei) living in the Ashburton River and discovered that 44 percent of the catfish sampled had consumed mice. While the number of mice eaten varied from fish to fish, they made up as much as 95 percent of the stomach contents of some catfish. That is, mice weren’t just an occasional treat for the catfish—they were an important part of the species’ diet.

While other species of fish have been known to eat terrestrial mammals, scientists were surprised to learn of the lesser salmon catfish’s predilection for mice. The species was previously thought to subsist predominantly on plants and aquatic invertebrates, and had never before been observed consuming mammals.

In fact, scientists still aren’t sure how the lesser salmon catfish are catching their mice. Though they’ve seen the mice in the fish’s stomachs, they haven’t been able to observe them feeding. While it’s possible the catfish are snapping up mice that get too close to the water’s edge, it’s also possible they’re simply eating mice that have fallen into the river and drowned.

Scientists will likely launch further attempts to get to the bottom of their catfish mystery. Researcher Erin Kelly tells New Scientist that as the effects of climate change are increasingly felt, the diet of the lesser salmon catfish becomes more important.

“Climate projections for north-western Australia indicate that we’re going to see both longer periods of drought and more intense rainfall events,” Kelly explains. “Changes in periods of flooding could possibly be altering the food web of these fish.”

[h/t New Scientist]

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