Spiral shark intestines work like Nikola Tesla’s water valve, study finds

A CT scan image of the spiral intestine of a Pacific spiny dogfish shark (<em>Squalus suckleyi</em>). The beginning of the intestine is on the left, and the end is on the right.

Enlarge / A CT scan image of the spiral intestine of a Pacific spiny dogfish shark (Squalus suckleyi). The beginning of the intestine is on the left, and the end is on the right. (credit: Samantha Leigh/California State University, Dominguez Hills)

In 1920, Serbian-born inventor Nikola Tesla designed and patented what he called a “valvular conduit“: a pipe whose internal design ensures that a fluid will flow in one preferred direction, with no need for moving parts, making it ideal for microfluidics applications, among other uses. According to a recent paper published in the Proceedings of the Royal Society B, the Tesla valve also provides a useful model for how food moves through the digestive system of many species of shark. Based on new CT scans of shark intestines, scientists have concluded that the intestines are naturally occurring Tesla valves.

“It’s high time that some modern technology was used to look at these really amazing spiral intestines of sharks,” said co-author Samantha Leigh of California State University, Dominguez Hills. “We developed a new method to digitally scan these tissues and now can look at the soft tissues in such great detail without having to slice into them.”

The key to Tesla’s ingenious valve design is a set of interconnected, asymmetric, tear-shaped loops. In his patent application, Tesla described this series of 11 flow-control segments as being made of “enlargements, recessions, projections, baffles, or buckets which, while offering virtually no resistant to the passage of fluid in one direction, other than surface friction, constitute an almost impassable barrier to its flow in the opposite direction.” And because it achieves this with no moving parts, a Tesla valve is much more resistant to the wear and tear of frequent operation.

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#applied-biology, #biology, #biomimicry, #ct-scanning, #science, #sharks, #tesla-water-valve

When Euphemisms (but Never Sharks) Attack

Plus, orphaned grizzlies, baby deer in the shower, hoot-owl restrictions and more in the Friday edition of the Science Times newsletter.

#extraterrestrial-life, #sharks, #young-men-and-fire-a-true-story-of-the-mann-gulch-fire-book, #your-feed-animals, #your-feed-science

Cold-case files: Archaeologists discover 3,000-year-old victim of shark attack

Original excavation photograph of Tsukumo No. 24, a young adult male with evidence of severe trauma consistent with an attack by a white or tiger shark.

Enlarge / Original excavation photograph of Tsukumo No. 24, a young adult male with evidence of severe trauma consistent with an attack by a white or tiger shark. (credit: Kyoto University)

Marine biologists have spent decades counteracting the popular misconception of sharks as aggressive predators that target humans, particularly in the wake of the blockbuster Jaws franchise. But fatal attacks nonetheless do happen—and they happened even in prehistoric times. While examining the skeletal remains of a prehistoric hunter-gatherer cemetery in Japan dating back some 3,000 years, University of Oxford archaeologists found distinctive evidence that one such skeleton had been the victim of a fatal shark attack. They described their findings in a new paper published in the Journal of Archaeological Science: Reports. It’s the oldest known victim of a shark attack yet—like a prehistoric cold-case film.

The Tsukumo burial site in Japan’s Okayama Prefecture was discovered by construction workers in the 1860s and first excavated in 1915. More than 170 human skeletons were unearthed and housed at Kyoto University. The site dates to the Late-Final Jōmon period of the Japanese archipelago. Co-authors J. Alyssa White and Rick Schulting, both from Oxford, made their discovery while examining the remains for evidence of violent trauma, part of a larger study on violence in prehistoric Japan. Remains categorized as Tsukumo No. 24 showed marks of severe trauma that proved especially puzzling.

“We were initially flummoxed by what could have caused at least 790 deep, serrated injuries to this man,” said White and Schulting. “There were so many injuries and yet he was buried in the community burial ground, the Tsukumo Shell-mound cemetery site. The injuries were mainly confined to the arms, legs, and front of the chest and abdomen. Through a process of elimination, we ruled out human conflict and more commonly-reported animal predators or scavengers.”

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#archaeology, #forensic-archaeology, #physical-anthropology, #science, #sharks, #tsukumo

Sharks Nearly Went Extinct 19 Million Years Ago From Mystery Event

Analysis of the fossil record shows a mysterious mass extinction that decimated the diversity of sharks in the world’s oceans, and they’ve never fully recovered.

#endangered-and-extinct-species, #fossils, #oceans-and-seas, #paleontology, #research, #science-journal, #sharks, #your-feed-science

The world saw a shark-pocalypse 19 million years ago, and we don’t know why

The outline of a shark traced with shark scales.

Enlarge (credit: Leah D. Rubin)

Sharks have been swimming and hunting in the world’s oceans for 450 million years, and though their numbers have recently declined because of human activity, they’re still with us. But the world once had many more, and many more varieties of, the large marine predators compared to today. In fact, new research published in Science suggests that 19 million years ago, the vast majority of sharks and shark species died off. We don’t understand why or how this large extinction event occurred.

“Sharks have… weathered a large number of mass extinctions. And this extinction event is probably the biggest one they’ve ever seen. Something big must have happened,” Elizabeth Sibert, one of the authors of the paper, told Ars.

Sibert is a Hutchinson postdoctoral fellow at the Yale Institute for Biospheric Sciences, and she was a junior fellow in the Harvard Society of Fellows for the initial phases of this research back in 2017.

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#extinction-event, #fossils, #ocean-science, #science, #sharks

The Price They Pay for Your Perfect Vacation Photo

Scientists are concerned about unregulated feeding of ocean wildlife by tour operators.

#animal-behavior, #australia, #bahama-islands, #conservation-of-resources, #endangered-and-extinct-species, #fish-and-other-marine-life, #greece, #marine-biology, #philippines, #photography, #research, #sharks, #travel-and-vacations, #turtles-and-tortoises, #your-feed-animals, #your-feed-science

New York Man Kept Sharks in Pool in His Basement

Investigators found seven sandbar sharks in an aboveground pool in a house in Dutchess County, the authorities said. The case spotlighted an underground market for exotic and protected fish.

#aquariums, #dutchess-county-ny, #endangered-and-extinct-species, #seguine-joshua, #sharks, #wildlife-trade-and-poaching

Largest Glowing Shark Species Discovered Near New Zealand

It’s the biggest bioluminescent vertebrate found on land or sea, so far.

#animal-behavior, #biology-and-biochemistry, #frontiers-in-marine-science-journal, #hormones, #light, #new-zealand, #research, #sharks, #your-feed-animals, #your-feed-science

Shark Populations Are Crashing, With a ‘Very Small Window’ to Avert Disaster

Oceanic sharks and rays have declined more than 70 percent since 1970, mainly because of overfishing, according to a new study.

#endangered-and-extinct-species, #fishing-commercial, #research, #sharks

Baby Megalodons Were 6-Foot-Long Womb Cannibals, Study Suggests

The research appears to confirm that, even as newborns, the extinct sharks were very, very big.

#longevity, #paleontology, #research, #sharks, #spine-body-part, #your-feed-science

The Problem With Problem Sharks

A marine biologist’s ideas for singling out sharks that attack humans have prompted objections from other shark scientists.

#animal-behavior, #animal-cognition, #clua-eric, #conservation-of-resources, #fish-and-other-marine-life, #french-polynesia-france, #hunting-and-trapping, #indian-ocean, #marine-biology, #research, #reunion-island, #sharks, #your-feed-animals, #your-feed-science

Will Ghost Sharks Vanish Before Scientists Can Study Them?

Much remains to be learned about the cartilaginous, little understood fishes that inhabit the deep-sea.

#endangered-and-extinct-species, #fish-and-fisheries-journal, #research, #sharks, #your-feed-animals, #your-feed-science

Surfer Dies After Shark Attack in Hawaii

The 56-year-old man died a day after the attack in Maui. A surf competition scheduled in the area later that day was postponed and moved.

#hawaii, #maui-hawaii, #sharks, #surfing, #world-surf-league

Australian Shark Attacks Jump, Raising Questions

Eight people have been fatally attacked this year, the most in nearly a century. But scientists say these numbers don’t tell the full story.

#animal-abuse-rights-and-welfare, #animal-behavior, #australia, #beaches, #oceans-and-seas, #sharks, #surfing

When Sharks Turned Up at Their Beach, They Called in Drones

A goal of the SharkEye project is to one day produce automated “shark reports” for beachgoers to help them gauge levels of risk.

#artificial-intelligence, #beaches, #california, #drones-pilotless-planes, #research, #santa-barbara-calif, #sharks, #your-feed-science

Sharks Wash Up on Beaches, Stabbed by Swordfish

The discovery of impaled sharks on Mediterranean shores backs up old fishermen’s tales of the marine predators dueling with swordfish.

#fish-and-other-marine-life, #ichthyological-research-journal, #libya, #mediterranean-sea, #research, #sharks, #spain, #your-feed-animals, #your-feed-science

Coronavirus Vaccine Makers Are Not Mass-Slaughtering Sharks

Some coronavirus vaccines rely on a shark-based product, but that doesn’t mean you shouldn’t get immunized.

#conservation-of-resources, #coronavirus-2019-ncov, #cosmetics-and-toiletries, #glaxosmithkline-plc, #sharks, #vaccination-and-immunization

The Pros and Cons of Being a Hammerhead Shark

A new study suggests that the ocean’s strangest-looking headgear is difficult to tote around.

#biology-and-biochemistry, #engineering-and-engineers, #oceans-and-seas, #physics, #research, #sharks, #your-feed-animals, #your-feed-science

Drones, Hooks and Blood: Secrets of the Shark Fishermen of Long Island

‘I don’t want to encourage other people to do this.’

#animal-abuse-rights-and-welfare, #endangered-and-extinct-species, #environmental-conservation-department-nys, #fishing-sport, #long-island-ny, #national-oceanic-and-atmospheric-administration, #sharks

International Crime Ring That Trafficked in Shark Fins Is Dismantled, U.S. Says

Law enforcement agents documented the harvest of more than six tons of shark fins, officials said.

#drug-abuse-and-traffic, #georgia, #hong-kong, #marijuana, #mexico, #money-laundering, #organized-crime, #search-and-seizure, #sharks, #soups, #united-states, #wildlife-trade-and-poaching, #xing-zhao-wu-terry

How to Survive in the ‘Shark Attack Capital of the World’

To live in New Smyrna Beach, Fla., is to know sharks and forget fear.

#beaches, #florida, #international-shark-attack-file, #sharks, #surfing

It’s Always the Summer of the Shark

Even during a pandemic, we cannot get the white shark out of our minds. Despite the rare attack, experts say humans have little to fear.

#animal-behavior, #beaches, #benchley-peter, #california, #california-state-university-long-beach, #cape-cod-mass, #capuzzo-michael, #conservation-of-resources, #east-coast-us, #fish-and-other-marine-life, #sharks, #surfing, #swimming

Swimmer in Maine Is Killed by Great White Shark in Rare Attack

A 63-year-old woman died in the state’s first recorded fatal shark attack, the authorities said. Sharks rarely attack humans but are following seals, their natural prey, north, experts say.

#fish-and-other-marine-life, #international-shark-attack-file, #maine, #marine-resources-department-maine, #sharks

The Real Horror of ‘Jaws’ Isn’t the Shark

It’s the leader who initially values capitalism over saving lives.

#coronavirus-reopenings, #drive-in-theaters, #movies, #sharks, #summer-season, #wellfleet-mass

Come to the Beach but Beware of Sharks, Cape Cod Officials Say

Visitors are being urged to be wary of sharks this July 4 weekend while remaining vigilant about slowing the spread of the coronavirus.

#animal-behavior, #atlantic-ocean, #beaches, #cape-cod-mass, #cape-cod-national-seashore, #coronavirus-2019-ncov, #coronavirus-reopenings, #fish-and-other-marine-life, #sharks

They Wanted You to Bet on Sharks. The Odds Were Not in Their Favor.

Gambling on shark migration patterns could raise awareness, some experts say. But it could also fuel the animals’ reputation as mere entertainment.

#animal-migration, #computers-and-the-internet, #conservation-of-resources, #fischer-chris-marine-researcher, #gambling, #mybookie-sportsbook, #ocearch, #sharks, #your-feed-animals, #your-feed-science

Shark Attack Kills Surfer in Northern California

Ben Kelly, 26, who designed boards for a living, was surfing at Manresa State Beach near Santa Cruz when he was attacked.

#california, #international-shark-attack-file, #santa-cruz-calif, #sharks, #surfing, #woods-hole-oceanographic-institution

Katharine, the Great White Shark Who Ghosted Her Trackers, Resurfaces

The last that researchers heard from Katharine via her transmitter was nearly a year ago, leaving her fate a mystery. Recently, though, there came some weak pings.

#cape-cod-mass, #fischer-chris, #fish-and-other-marine-life, #katharine, #oceans-and-seas, #ocearch, #research, #sharks