Scientists successfully capture the first baleen whale for hearing study

Scientists recently performed a groundbreaking test on a baleen whale to assess its hearing abilities. This controversial step is bringing scientists closer to understanding how the largest and most intelligent creatures on Earth perceive the world.

In 2023, researchers captured two young minke whales off the coast of Norway, attached electrodes to their skin using suction cups, and measured their brain waves while playing tones at various frequencies. The young whales were both over 12 feet long and weighed around one ton each.

The findings of the research, published in Science on Thursday, surprised whale researchers by suggesting that whales have the ability to hear much higher frequencies than previously thought, exceeding the hearing capabilities of most mammals, including humans.

Dorian Hauser, the study’s lead author and director of conservation biology at the National Marine Mammal Foundation, described the discovery as “a little shocking.” He explained that whales have ultrasonic hearing, likely to detect killer whales, their primary predators, as they hunt prey using echolocation signals in a similar frequency range.

The startling revelation comes at a time of increasing concern over the impact of ocean noise from sources like naval sonar, oil and gas exploration, and shipping traffic, which can alter marine mammal behavior, cause hearing loss, and even lead to death. This new information may lead to revising regulations under the Marine Mammal Protection Act and restricting certain activities.

Susan Parks, a biology professor at Syracuse University, stated, “High-frequency sound from ocean activities has not typically been considered a threat to baleen whales, but this may now need to be reevaluated,” as mentioned in the study.

The research concluded a longstanding disagreement in the whale research community. Previously, baleen whales were never captured for hearing tests due to safety concerns for both the whales and researchers, given their large size.

Certain scientists and activists opposed the four-year Minke Whale Hearing Project, fearing the whales could experience stress and even mortality during brief captivity. The project faced criticism, with organizations like Whale and Dolphin Conservation advocating against it in an open letter to the Norwegian government.

The hearing abilities of the largest whale species on Earth have long been a mystery due to the limitations of studying these massive creatures in captivity. However, through innovative methods like the Minke Whale Hearing Project, researchers are making strides in understanding how these animals experience the world through sound.

Brandon Southall, a scientist involved in developing standards for ocean sound exposure, believes that the research could influence future regulations to protect marine mammals from harmful underwater noise sources. He emphasized the importance of conducting such studies carefully and professionally to guide conservation efforts.

While the Minke Whale Hearing Project is currently on hold, researchers hope to continue the exploration of these fascinating creatures’ hearing abilities should further funding become available.

Source: www.nbcnews.com

New Fossil Discovery Shows Baleen Whales Adapted to Large Bodies in Cold Southern Waters for the First Time

Baleen whales (mysterious animals) are the largest animals on Earth. How they achieved such enormous sizes is still debated, and research to date has focused primarily on when they grew, rather than where they grew. was. Paleontologists now report on the remains of a toothless baleen whale (chaeomysticete) from South Australia. At an estimated length of 9 meters, it is the largest baleen whale from the early Miocene. Analysis of body size over time shows that ancient baleen whales in the Southern Hemisphere were larger than those in the Northern Hemisphere.

Mysterious gigantism from the early Miocene. Image credit: Ruairidh Duncan

It was previously thought that the onset of the Ice Age in the Northern Hemisphere about 3 million years ago triggered the evolution of truly gigantic baleen whales.

The new study, led by Dr James Rule of Monash University and the Natural History Museum in London, reveals that this evolutionary size jump did, in fact, occur as early as 20 million years ago, and in the exact opposite direction in the southern hemisphere. I made it.

The major discovery came from a study of 16- to 21-million-year-old fossils held in Museum Victoria’s collection.

This specimen, the anterior end of the lower jaw of a large edentulous baleen whale, was discovered in 1921 on a cliff face on the banks of the Murray River in South Australia, but was largely unrecognized in collections.

In their study, Dr. Ruhl and colleagues explain how whales evolved to be larger in the southern hemisphere rather than the northern hemisphere, and that whales have been larger in the southern hemisphere throughout their evolutionary history (about 20 million to 30 million years). It was shown that

The discovery highlights the vital importance of the Australian and wider Southern Hemisphere fossil record in putting together a global picture of whale evolution.

The Murray River whale fossil confounds that theory, although previous leading theories were based primarily on fossils found in the northern hemisphere.

“The Southern Hemisphere, and Australia in particular, has always been overlooked as a frontier for fossil whale discovery,” says Dr Eric Fitzgerald, a palaeontologist at Museums Victoria Research Institute.

“Like the Murray River whale, the fossil whale discoveries in the south have shaken up whale evolution, giving us a more accurate, truly global picture of what was happening in the oceans in ancient times. .”

Researchers have discovered that the tip of a baleen whale’s jaw can expand depending on its body size.

They estimated the baleen whale to be about 9 meters long.

“The largest whales alive today, such as the blue whale, reach the length of a basketball court,” Dr. Ruhl said.

“About 19 million years ago, Murray River whales were nine meters long, already a third of this length. So baleen whales were well on their way to becoming ocean giants.”

of result will appear in Proceedings of the Royal Society B.

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James P. Rule other. 2023. A huge baleen whale emerges from its cold cradle in the south. Procedure R. Soc. B 290 (2013): 20232177; doi: 10.1098/rspb.2023.2177

Source: www.sci.news