Researchers analyzing humpback whale calls with information theory claim the animals may have a hierarchical grammar. The study measured entropy in the songs, finding predictable sequences of sounds that hint at complex communication.
Killer whales have begun preying on sea otters in western Alaska, leading to a decline in sea otter populations and an increase in sea urchin numbers. This chain of events is linked to the collapse of seals and sea lions, which are the killer whales' usual prey.
Researchers attribute sharp declines in sea otter numbers to killer whale predation, linked to changes in oceanic and nearshore ecosystems. The study highlights the impact of ecological chain reactions on coastal food webs and species populations.
Penn State researchers develop a finite difference method to simulate sonic boom noise for both simple and complex ocean surfaces. The new technique allows for accurate predictions of underwater noise, paving the way for the development of supersonic passenger aircraft with minimal impact on marine life.
A Cornell University team found no overt response from humpback whales to the Acoustic Thermometry of Ocean Climate (ATOC) simulation sounds in Hawaiian waters. The whales swam normally near the underwater speakers, with some even singing close to the speaker.