Water buffaloes in Turkey have been spotted carrying some unusual hitchhikers—tiny frogs.
In autumn, farmers along the Black Sea coast release their domesticated Anatolian water buffalo to wallow in the marshes, where a menagerie of marsh frogs hops onboard, a new study says. (Read "Dolphins on Whales, and Other Animals Riding Animals.")
“The initial observation was accidental, as is often the case in ecological research,” says study leader Piotr Zduniak, who saw the spectacle while birdwatching in the Kizilirmak Delta, one of the Middle East's largest wetlands.
Zduniak, an ecologist at Poland's Adam Mickiewicz University, and colleagues returned the next fall to northern Turkey and observed 10 more occasions in which marsh frogs clung to buffalo backs and heads. (Read "Weasel Rides Woodpecker in Viral Photo—But Is It Real?")
One buffalo was covered with a whopping 27 frogs, though the average number of amphibians per ungulate was between two and five, according to the paper in the journal Acta Herpetologica.
So why were the frogs hitching rides? There's one strong clue: Most of the frogs were eating insects that live in the buffaloes' shaggy coat, similar to how some birds feed on large mammals.
Additionally, the scientists observed the frogs jumping on the buffalo in the fall, when frog numbers are plentiful and competition for food is fierce.
In addition to providing a free meal, Zduniak adds, "the warm-blooded mammals are like heaters for the cold-blooded amphibians, which could be important when the temperature is low.”
Not only that, but the buffalo may also benefit from its froggy friends by removing disease-causing—or simply bothersome—flies and parasites. (See "Seal Catches Ride on Whale. Why Does This Keep Happening?")
If true, the phenomenon could be considered mutualism, Zduniak says—a reciprocal behavior among species that benefits both parties.
Friends With Benefits?
Mutualism is rare between vertebrates, notes Judith Bronstein, an ecologist at the University of Arizona.
“The best understood cases of mutualism between two vertebrate species involve one species that removes parasites from the other, like cleaner fish and their host fish," says Bronstein, who was not involved in the frog-buffalo study.
Other examples include species that work together to look out for predators, such as birds that form mixed-species flocks. (See "Turtles Groom Warthog in Never-Before-Seen Behavior.")
But for the odd relationship to qualify as mutualistic, she cautions, more evidence is needed to show a measurable benefit for each partner.
“The jury is out on what the nature of the interaction is," says Bronstein, "but if I had to put down money, it would be that it isn’t a mutualism.”
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