SCIENCE

A shark breaks its silence with some clicking sounds

Dolphins whistle. Whales sing. Fish croak, chirp, grunt, hum and growl. But in the chatter of the sea, one voice has been missing — until now.

Sharks have long been seen as the silent killers of the water. But scientists at the University of Auckland in New Zealand recently recorded a rig shark, or Mustelus lenticulatus, making a sharp clicking sound, most likely by snapping its teeth together, according to findings published in the journal Royal Society Open Science on Wednesday. They believe it’s the first time a shark has been recorded actively making noise.

The lead researcher, Carolin Nieder, first heard the sound while she was researching the hearing abilities of sharks. While she was handling one shark, it made a clicking, snapping sound similar to that of an electric spark, she said.

They did not make the noise when they were feeding or swimming, leading the scientists to believe the clicking was more likely something they did when stressed or startled, rather than as a means of communicating.

CLIMATE

Global sea ice hits a new low, U.S. scientists say

Earth is missing a lot of sea ice this year. Enough to cover the entire United States east of the Mississippi.

That was announced Thursday by researchers at NASA and the National Snow and Ice Data Center, who said the amount of sea ice on the planet had reached the lowest level ever recorded in March.

The record comes days after the World Meteorological Organization reported that the past 10 years have been the 10 hottest on record, with 2024 the hottest year. The global rise in temperatures is tied to increasing concentrations of greenhouse gases, largely caused by the burning of fossil fuels.

“Warming temperatures drive melting ice across the globe, and because we’re seeing such high temperatures, it’s not surprising that this year we’re seeing the least amount of ice coverage,” said Linette Boisvert, an ice scientist at NASA’s Goddard Space Flight Center.

The center has been compiling data for almost 50 years, primarily through a Department of Defense satellite program. The global sea ice extent includes measurements taken in the Southern Hemisphere and the Northern Hemisphere.

Sea ice plays many important roles for the global climate: Its white surface can reflect energy back into space, helping the planet cool. It also acts like a blanket for the ocean, insulating it and preventing ocean heat from reaching the atmosphere.

— Denver Post wire services