快猫短视频

WILD dolphins do impressions, mimicking the whistles of their pod mates. But
rather than just being a party trick, the ability may be a crucial early step in
the development of language.

Vincent Janik, now at the Woods Hole Oceanographic Institution in
Massachusetts, used hydrophones to listen to bottlenose dolphins in the Moray
Firth, north-east Scotland. The difference in the time a sound takes to travel
to each of a pair of hydrophones depends on where the sound is coming from. By
comparing these differences across 3 pairs of hydrophones, Janik could
triangulate a whistling dolphin鈥檚 position to within 13 metres.

Pinpointing the location of each whistling dolphin helped Janik to unravel
the interactions between them. Often he found that one dolphin would produce a
distinctive set of whistles, only to have them immediately copied by another
dolphin a few hundred metres away.

Wild dolphins often leave and rejoin their groups, and Janik suggests mimicry
may allow a returning dolphin to re-establish contact. The dolphins also produce
other whistles after one has copied another. 鈥淚t seems extra information is
exchanged after contact is established,鈥� he says.

Being able to learn new vocal signals from each other may have been an
important skill in the development of human language, Janik points out. While
many birds are great vocal mimics, dolphins are the only mammals apart from
humans known to have this ability.