Just like people in a noisy location, North American right whales virtually 'shout' to be heard above the levels of environmental noise, says a study.
Whales produce upcalls, sometimes called contact calls, when they are alone or in the process of joining other whales. An upcall begins low and rises in pitch. It is the most frequent call produced by right whales.
Right whales are large baleen whales that tend to approach close to shore. They may have been given the name because they were the right whales to hunt as they are rich in blubber, slow swimming and remain afloat after death.
Susan Parks, assistant professor of acoustics in Penn State University, and fellow researchers looked at individual North Atlantic right whales in varying environmental noise situations.
"The impact of human activities in increasing ocean noise is a concern for the conservation of marine animals like right whales," said Parks, who led the study.
"The ability to change vocalisations to compensate for environmental noise is critical for successful communication in an increasingly noisy ocean," Parks added.
"Right whale upcalls are used extensively for passive acoustic monitoring in conservation efforts to protect this endangered species," a university statement quoted Parks as saying.
These findings appeared in Tuesday's issue of Biology Letters.