"Maybe he only speaks whale."
This is Sandra Tsing Loh with the Loh Down on Science, quoting Dory from "Finding Nemo."
Silly Dory. Only whales speak whale. Or maybe not....
Researchers studied five performing bottlenose dolphins at France's Planete Sauvage dolphinarium.
During the day, the dolphins frolic to a soundtrack of music, dolphin whistles, seagull calls, and humpback whale sounds. The dolphins whistle and click as they play.
Previously, no one has known whether dolphins vocalize when at rest. So the researchers placed underwater microphones in the dolphins' tank for a week, to record their vocalizations, day and night.
In listening, the team discovered something surprising. At night, the dolphins made noises they never made during day: they mimicked whales!
Spectrograms showed that the dolphins' sounds and real humpback sounds were very similar. So similar, in fact, that human test subjects couldn't tell them apart.
Why the dolphins don't mimic whales during daytime is mysterious, making the team think maybe the dolphins are doing it in their sleep.
You might say they aren't doing it on porpoise! Or not.
The Loh Down on Science, online, at lohdown.org. Produced by 89.3 KPCC and the California Institute of Technology, and made possible by TIAA-CREF.
Follow us on Twitter at LohDown.