Pack says that dolphins use broadband clicks for echolocation. Dolphins will imitate the signature whistle of close companions. Mothers, when separated from young, may mimic their youngster's signature whistle to call them, and close companions mimic each other when they're separated. Frog filters At the other end of the size spectrum, sound frequency also appears to be a critical element in frog and even insect communication. Frogs have developed the ability to filter the distinct frequencies and rhythms of their own species' calls through a thick curtain of background sounds in a jungle.
Some frogs care about the frequency of a call, others about the timing.
The females of the species can hear only that frequency, which tends to be right around 5,000 herz, says Kenneth Prestwich, a biologist at the College of the Holy Cross. Like birds and whales, frogs and crickets have only one or two things in mind when they're creating those pleasing calls. There's no question that frog calls can be melodious. The sounds are beautiful and melodic and can be everything that music is, but it isn't an artificial score. And that's the distinction.