The fox froze. Inches from his legs, a frantic spawning carp writhed in the shallows along the edge of a reservoir. In a sudden movement, the fox dove nose-first into the water, emerging with a large wriggling carp in its mouth.
In March 2016, two researchers in Spain observed a male red fox (vulpes vulpes) stalked and caught 10 carp in a couple of hours. The event, described in a study published August 18 in Ecology, appears to be the first recorded case of a fox fishing, the researchers say. The discovery makes red foxes the second type of canid, the group that includes wolves and dogs, known to hunt fish.
“Seeing the fox hunting carp one after another was incredible,” says ecologist Jorge Tobajas of the University of Córdoba. “We have been studying this species for years, but we never expected something like this.”
Tobajas and his colleague Francisco Díaz-Ruiz from the University of Malaga came across the fishing fox while inspecting a site for a different project. The fox first caught his attention because it didn’t immediately run away when it saw the investigators. Seizing the opportunity, Tobajas and Díaz-Ruiz decided to hide nearby and see what the fox was up to.
His curiosity turned to excitement after the fox caught his first fish. “The most surprising thing was to see how the fox hunted many carp without making any mistakes,” says Tobajas. “This made us realize that it was surely not the first time he had done it.”
Instead of immediately gobbling up all the fish, the fox hid most of its catch and appeared to share at least one fish with a female fox, possibly its mate.
Fish remains have been seen in fox droppings before. But the scientists weren’t sure whether the foxes had caught the fish themselves or were simply rummaging through dead fish. This research confirms that some foxes fish for food, says Thomas Gable, a wildlife ecologist at the University of Minnesota in Minneapolis who was not involved in the research.
“I’d be surprised if this was the only fox that learned to fish,” says Gable.
Wolves that live on the Pacific coast of North America and in Minnesota they are the only other canids known to fish (Serial number: 02/11/20). The fact that two canid species live on separate continents opens up the possibility that the behavior is more common than previously thought, says Gable.
For Tobajas, the fishing fox is an example of how much scientists still don’t know about the natural world, even for species that live fairly close to humans. “The red fox is a very common species and in many cases it’s a bit hated,” he says. Foxes sometimes attack pets or livestock and are considered a pest in many places. But “observations like this show us that it is a fascinating and highly intelligent animal.”