快猫短视频

HUMPBACK whales change their tune according to the season, and now
researchers think they know why. In response to changes in sea temperature, the
whales adapt their calls so they can be heard by other humpbacks over the
longest possible distance. The discovery may help naval ships and submarines
spot enemy vessels.

Humpbacks sing over different frequency ranges depending on the time of year,
says Eduardo Mercado of Rutgers University in New Jersey. 快猫短视频s had
attributed this to the way whale behaviour changes with the season: in the
summer, humpbacks are mainly concerned with feeding, while winter is primarily a
breeding season. But Mercado felt something else was making humpbacks change
their tunes.

To investigate, he ran computer simulations of how far whale songs travel
through water in different seasons. Sound propagation depends on seasonal
factors such as the temperature of the sea. His results were unambiguous. 鈥淭o
achieve maximal propagation ranges, humpbacks should use lower frequencies in
summer environments and higher frequencies in winter,鈥� he says. When he compared
his results with published frequency ranges for humpback whales in different
seasons, he found this was exactly how the whales vary their song.

Mercado announced his results this week at the Oceans 2000 conference in
Providence, Rhode Island. He says that a better understanding of whale song
could allow the military to spot enemy vessels covertly, as the sound waves
alter their frequencies when they bounce off an object.

Mercado concedes that his method has its limitations鈥攏ot least that
whales have to be in the waters the military want to patrol.