Are all ribbits created equal? No. At least not those of the Pacific Tree Frogs, whose mating calls can be heard this week on the west coast of the United States. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.
“We’re in a suburb of Seattle, Washington now, with a little pond in front of us. It is maybe fifteen feet across. The water’s shallow, never much deeper than your knees. It’s a rather typical place where you find these Pacific Tree Frogs breeding.”
Frank Awbrey is a retired Professor of Biology from San Diego State University, who’s studied the calls of Pacific Tree Frogs.
“Pacific Tree Frogs’ mating calls and other calls that they use on the ponds are strictly given during the mating season, which runs from about December into June. Only the males call, and it’s to provide the female with information about the species of the frog: that he’s male, that he’s in the right place for mating, and that he’s in condition to mate.”
During mating season, each of the male’s calls has a specific meaning. For example, this call is meant to attract a potential mate.
ambience: Pacific Tree Frog monophasic call
“A male switches from his ribbit call to this call when he senses another frog near him which is likely to be a female.”
And the male frog definitely wouldn’t want confuse that call with this one.
ambience: Pacific Tree Frog trill call
“That is an aggression call, and it tells the other frog ‘either shut up or move away.’ And if the other frog won’t do it, he’ll actually fight. It’s hard to imagine frogs getting in to much of a fight, but they do. They’ll battle it out.”
Pulse of the Planet is presented by the American Museum of Natural History. I’m Jim Metzner.