The fox froze near a reservoir’s shore. Inches from its paws, frenzied, spawning carp writhed in the shallow water. In a sudden flash of movement, the fox dove nose-first into the water. It emerged with a large carp wriggling in its mouth.
In March 2016, two researchers in Spain watched this male red fox (Vulpes vulpes) hunting. It stalked and caught 10 carp over a few hours. The event seems to be the first recorded instance of a fox fishing, the researchers say. The scientists described what they saw August 18 in the journal Ecology. Their observation makes red foxes just the second species of canid known to hunt fish. (Canids are the group of mammals that includes wolves and dogs.)
“Seeing the fox hunting carp one after another was incredible,” recalls ecologist Jorge Tobajas. He works at the University of Córdoba in Spain. “We have been studying this species for years, but we never expected something like this.”
Tobajas and his colleague Francisco Díaz-Ruiz stumbled across the fishing fox by accident. Díaz-Ruiz is an animal biologist. He works in Spain at the University of Málaga. The two were surveying the site for a different project when they spotted the fox. It caught their attention because it didn’t flee when it saw them. Curious as to why, Tobajas and Díaz-Ruiz decided to hide nearby and see what the fox was up to.
That curiosity turned into excitement after the fox caught its first fish. “The most surprising thing was to see how the fox hunted many carp without making any mistakes,” Tobajas says. “This made us realize that it was surely not the first time he had done it.”
The fox didn’t eat all of the fish right away. Instead, it hid most of the catch. It appeared to share at least one fish with a female fox, possibly its mate.
Fish remains have been found in fox scat before. But scientists weren’t sure whether foxes had caught the fish themselves or were simply scavenging dead fish. This research confirms that some foxes fish for their food, says Thomas Gable at the University of Minnesota in Minneapolis. A wildlife ecologist, he wasn’t involved in the research.
“I would be shocked if this was the only fox to have learned how to fish,” He adds.
Before this finding, wolves were the only canid known to fish. Those wolves were living on the Pacific coast of North America and in Minnesota. It’s notable that two canid species living on separate continents both fish, Gable says. It could mean the behavior is more common than scientists had thought.
Tobajas sees another lesson in the fishing fox. There are still many things scientists don’t know about the natural world, even about species that live fairly close to people. “The red fox is a very common species and is in many cases a bit hated,” he says. In many places, they are considered a pest for attacking pets or livestock. But “observations like this show us that it is a fascinating and very intelligent animal.”