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Bird-Snatching Tigerfish: Freshwater Species of the Week

Earlier this week we reported on the first confirmed video that shows what many people had long feared: that some fish can leap out of the water and snatch birds in midair. That fish is the tigerfish, a “megafish” that dwells in lakes in Africa, and which has large, razor-sharp teeth.

Widely distributed across much of Africa, tigerfish are fierce predators that often hunt in packs and have been known to occasionally eat larger animals. Attacks on human beings are rare but not unheard of.

The two largest species of tigerfish are the goliath tigerfish (Hydrocynus goliath) and the Hydrocynus vittatus, which is commonly called the tigerfish. Both are prized as game fish.

tigerfish
This small tigerfish ( H. vittatus) was found in the upper Zambezi, near Livingstone, but the species can get a lot bigger. Photo: Viridiflavus, Wikimedia Commons

freshwater species of the weekThe goliath tigerfish, which can reach sizes up to 110 pounds (50 kg), is found in the Congo River and Lake Tanganyika. The non-goliath tigerfish can weigh up to 33 pounds (15 kg) and is found in the Zambezi River system.

As Jane Lee reported this week, scientists captured video of Hydrocynus vittatus tigerfish in February 2010 in a storage lake for the Schroda Dam in South Africa, and some were snatching barn swallows out of the air, as recorded in a study published online last month in the Journal of Fish Biology. Lee wrote:

Unlike other instances of fish eating birds, barn swallows actually seem to be a fairly regular part of a tigerfish’s summer diet when the swallows are available, [Nico Smit, director of the unit for environmental sciences and management at North-West University in Potchefstroom] said. “[The fish] have been incredibly well adapted to hunt the flying birds as part of their daily routine.”

Lee added:

The fish would either follow the birds in a surface pursuit before leaping up to try and catch them, or the tigerfish would track the swallows from deeper in the water and launch into the air to ambush them.

Smit marvels at the skill it takes for these fish to capture birds on the wing. Tigerfish have to spot a fast-flying swallow from the water, exceed the bird’s speed, compensate for refraction—or the fact that the angle of light changes when it goes from air to water—and then leap out of the water to grab the bird, he explained.

Over the course of their study, researchers saw up to 20 successful attempts on flying barn swallows by tigerfish in one day.

To accompany our story confirming barn swallows are eaten by african tigerfish, this graphic compares their length and weight.

Although such ravenous-looking fish might be the stuff of nightmares, they also play an important role in freshwater ecosystems, which are increasingly threatened. They also can be an important source of protein, and revenue, for local people.

Finally, they have their own intrinsic charm, says Zeb Hogan, a fish biologist, Water Currents contributor, and star of Monster Fish. “Freshwater fish, though not the cuddliest of creatures, have their own intrinsic value and beauty, just like each of us, and deserve our help,” he recently wrote.

 

Brian Clark Howard covers the environment for National Geographic. He previously served as an editor for TheDailyGreen.com and E/The Environmental Magazine, and has written for Popular Science, TheAtlantic.com, FastCompany.com, PopularMechanics.com, Yahoo!, MSN, and elsewhere. He is the co-author of six books, including Geothermal HVACGreen LightingBuild Your Own Small Wind Power System, and Rock Your Ugly Christmas Sweater.

Comments

  1. Ima Ryma
    January 18, 4:08 am

    Africa has no tiger cat,
    But boasts having the tigerfish.
    Oh my, what razor sharp teeth that
    I have to use in yearning wish
    To leap from lake into the air,
    And grab a bird that’s flying by.
    Quite a surprised bird that I’m there.
    What’s a fish doing in the sky?
    For me to do so takes great skill.
    First I must spot, then get up speed,
    Compensate angles, then I will
    Defy norm nature – yes indeed!

    A barn swallow comes into view.
    I leap and swallow – yes I do!