Video reveals baby steps of newly hatched ‘walking’ sharks

Some sharks can “walk” and researchers recently discovered how one of these unusual shark species trains itself to take baby steps. They start when they are newly hatched, and the walking of a hatchling is no different from that of older juveniles.

When the tide near a coral reef recedes, a small mat species shark is often overlooked. When stranded in shallow tidal pools with falling and rising oxygen levels temperatures – or worse, stranded on hot slabs of exposed reef – most aquatic species wouldn’t stand a chance. But the epaulette shark (Hemiscyllium ocellatum) can hold its breath for hours and tolerate a range of temperatures. And in a pinch, he can walk.

“At low tide, when the reef is exposed, you can see them walking on the reef,” said Marianne E. Porter, an associate professor at Florida Atlantic University who studies the mechanical structures and movement of sharks. She told Live Science that these sturdy little sharks can walk on land and underwater, floating on the substrate on four paddle-like fins for more than 90 feet (27 meters) until they find a suitable corner where they can wait for the tide.

It’s one of nature’s most distinctive survival strategies, yet few studies have examined the physics behind epaulette shark locomotion and gait. Now a new study in the journal Integrative and Comparative Biology is the first to describe the walking mechanisms of newly hatched epaulette sharks.

The findings could ultimately help scientists understand how other aquatic species will tolerate stresses from climate change, such as rising carbon dioxide levels.

“Epaulette sharks live at extremes,” said Porter, the study’s lead author. “If we want to know what happens to animals under the extremes of climate change, looking at animals already living in those conditions – and understanding how they move and adapt – can be the first step.”

Related: ‘Walking sharks’ captured on video amaze scientists

Puffy baby sharks

Porter and study co-author Jodie Rummer, a professor of marine biology at James Cook University in Australia, had been studying epaulette sharks for years, but were frustrated to discover that very little information existed. on how carpet sharks actually walk. The most recent study to examine epaulette shark locomotion was published in the late 1990s and focused exclusively on mature sharks. The issue of walking juveniles and baby sharks had never been addressed in the scientific literature.

Porter and Rummer suspected that baby sharks would walk differently from juveniles and older adults. Epaulette sharks are born bloated, their bellies distended with a yolk sac that meets all their nutritional needs for about a month until they are mature enough to feed on small fish and worms. Their baby fat then rolls off, giving way to the familiar spindle shape of an adult shark.

“Form usually impacts how we move,” Porter said. “Baby humans walk differently to balance their giant heads, and we speculated that baby sharks would wiggle their bodies and move their fins differently to accommodate their giant bellies.”

But after reviewing several videos of young sharks walking and swimming, the researchers were surprised to find that all young sharks, from newly hatched babies to yolk-sackless juveniles, seemed to move in the same way. This observation applies to several key parameters, including speed, tail-beat frequency, body flexion, and fin rotation.

“I really thought baby sharks would move differently,” Porter said. “But in science, we make our best guesses based on the available evidence, and our guess turned out to be wrong.”

Beyond walking sharks

It’s unclear why baby sharks don’t adopt gaits better suited to their bulbous bellies. A possible explanation is that gravity play a role. The recent study only looked at sharks walking underwater, where the volume of the yolk sac hardly impedes movement. In future studies, Porter hopes to see if baby sharks adjust their gait on land to account for the extra weight.

Further research into the locomotion of epaulette sharks may also be useful to evolutionary biologists who study the animals’ transition from water to land, as well as biomechanical researchers who, like Porter, study how fins and feet interact with surfaces and how animals respond to gravity and body shape. as you move through different environments.

Meanwhile, epaulette sharks are becoming models for scientists studying how marine fish are adapting to changing oceans. Studying how these unique sharks walk to safety may ultimately lead to a better understanding of how other species move through – and away from – harsh environmental conditions, including those associated with climate change.

“From an evolutionary perspective, from a climate change perspective, and even from a basic physiological perspective, we can learn a lot from epaulette sharks,” Porter said.

Originally posted on Live Science.

Comments are closed.