Sea turtles present stylish design solutions

Photo: Baby green sea turtle, by Tyler Karaszewski, via Flickr (cropped).

No doubt about it, from a scientific point of view, baby sea turtles emerging from their beach nests and crawling out to water on tiny flippers are extremely cute. Aside from being adorable, what many may not realize is that their movement on the sand is also incredibly effective. So much so that engineers are trying to imitate it for use in robots that have to go through loose materials.

write for Phys.OrgDaniel Goldman, a biomimetics engineer at the Georgia Institute of Technology, marvels:

The best robots people design and build can’t compete with a newborn sea turtle whose life consists of swimming all the time and using these appendages on land only half an hourfleeing the nest. [Emphasis added.]

In a video from Georgia Tech Research Horizons, Goldman explains how the turtle’s wrist flexibility is key to its efficient locomotion that can propel it across the beach at multiple body lengths per second over soft sand. The only other time the appendages are used for walking on land is years later when the females crawl up the shore to lay their eggs. For men, however, that unique sprint on the beach depends on well-designed legs that also work perfectly as swim fins for the rest of their life at sea.

Learn more about the turtle theme.

Glow in the Dark Turtle

Solomon Islands night divers were surprised to see a glow-in-the-dark sea turtle. They were filming a NOVA special, “Creatures of Light”, when a hawksbill turtle hovered like a bright red and green spaceship under their blue spotlights (the video below is via National geographic). The beautiful stripes and patterns on its shell took on a new lease of life when the turtle stayed with the divers for about five minutes.

This is the first sighting of a shiny reptile. Glow is a phenomenon called biofluorescence: the ability to absorb light energy and re-emit it (unlike bioluminescence, which emits chemical light). Biofluorescence is known in fish, jellyfish, corals and sharks. Divers and scientists don’t know how the turtle acquired this ability, or what function it plays in their ecology, but they were very excited to see this spectacular trait in a critically endangered species. Live Science says more about the rare encounter.

Leggings

Do sea turtles have cold feet? Nope, Science explains, because they are designed with large arteries and veins grouped together in their leg muscles in a special way.

Despite a low metabolic rateleatherback turtles – the only living species of turtle in a once larger group – have a core body temperature of between 25°C and 27°C (about 77°F to 81°F). Muscles need to stay warm to stay efficientbut it is a challenge for these beasts because they often swim in near-freezing waterseither in the cold regions of the world, or deep below the surface heated by the sun….

In addition to layers of insulating fat, which the scientists were already familiar with, the team noted the unusual pattern of major blood vessels in the leg muscles of turtles. The blood vessels are arranged so that veins that bring blood back to the center of the body give up the heat generated in still-active muscles to blood coming from the heart into the arteries, researchers report online today in Biology Letters.

This elegant solution not only keeps the muscles warm where energy is needed. It also helps the females not to overheat when performing the arduous task of carrying their heavy bodies across the beach and digging nests. Also consider that the arrangement must scale through several orders of magnitude from newborn to adult and still be effective at all scales. The heat transfer mechanism reminds me of the countercurrent heat exchanger in the male humpback whale testicles.

Turtle Diapers

What do sea turtles eat? To find out, researchers from the University of Queensland had to take fecal samples from loggerhead sea turtles. Finding a way to do this without hurting or disturbing the animals was a challenge, but they finally found a flexible swimsuit that adapts to the turtle’s tail. The giant layer worked perfectly, providing information that will help conservation efforts.

Environmental sex

Florida Atlantic University research highlights the little-known fact that sea turtles do not have X or Y sex chromosomes. Instead, an individual’s sex is determined by the environment during incubation. “Warmer conditions produce females and cooler conditions produce males. Under normal conditions, this arrangement apparently worked well. However, understanding the realities of turtle life will be important in predicting their response to climate change. The article helps you understand what this adult turtle went through to reach breeding age:

Loggerhead sea turtles are already fighting an uphill battle with around one in every 2,500 to 7,000 sea turtles reaching adulthood. The typical Loggerhead produces about 105 eggs per nesting season and should nest for more than 10 nesting seasons over a period of 20 to 30 years just to replace himself and possibly a companion. And, if enough males are not produced due to climate change, it will cause a serious problem for this species.

plastic hazard

Some humans don’t help adults who are successful in overcoming all these obstacles. The University of Exeter describes the problem of plastic pollution in the oceans. Beach trash – cups, straws and bags – doesn’t just stay on the beach. They often drift far out to sea where turtles, fish and marine mammals sometimes ingest them: “When turtles ingest plastic they can suffer from intestinal blockage which can lead to malnutrition which can in turn lead to poor health, reduced growth rates, reproductive problems. exit, and even death.

Captain Dave Anderson, who appears in the Illustra Media documentary Rapids, is a leading activist for rescuing animals entangled in fishing nets and plastic. Whales, he points out, have been known to ingest deflated mylar balloons because from below they are mistaken for jellyfish, which are part of their normal diet. He is currently working on a low-cost tracking tag that observers can attach to trapped animals so rescuers can locate them with the tools to cut the nets.

We all have a responsibility to preserve a safe habitat for critically endangered animals like sea turtles. A few minutes of watching this viral video that shows rescuers trying to pull a plastic straw out of a sea turtle’s nostril should cure even the most sensitive of waste:

Achievements

Not all is bad news on the conservation front. PhysOrg says endangered green sea turtles are nesting in record numbers in Florida, thanks to conservation efforts. The number of nests counted on state beaches has risen in four years from 10,700 to 28,000. This represents a huge rebound from the low of 464 nests around three decades ago. Green sea turtles nest on the beaches of 140 countries. They are threatened by habitat loss and fishing nets, but “measures in place to protect these habitats and the use of turtle-friendly fishing gear have contributed to the increase in numbers”.

Dr. Stephen Dunbar, who also appears in the film Illustra, is president of ProTECTOR, a conservation effort in Honduras that conducts research and also helps educate local fishers and government officials about the ecological value of sea turtles. . The acronym stands for “Protective Turtle Ecology Center for Training, Outreach and Research”. One of their innovative techniques is the “Bottles to Buildings” program, where citizens learn to use waste constructively instead of dumping it in the ocean.

The Turtle Explosion

Another Sea Turtle Story reports: “World’s Oldest Sea Turtle Fossil Discovered”. Live Science says a 120 million year old fossil sea turtle – 25 million years older than the previous record – has been discovered in Colombia. There are two problems here for the Darwinian evolutionist. First, this turtle is not primitive, but already highly specialized, as if it had just exploded onto the scene. The second is that it might not be related to living sea turtles, leading the discoverer to speculate that “other turtles later evolved in the same way from a separate ancestor.”

To make matters worse, the discoverer responded to resistance to his speculation by piling on more: “This shouldn’t be a wholly surprising theory, he added, because mammals, reptiles and other animals have evolved separately multiple times to produce a variety of marine species. pets. There are, however, good reasons to reject “convergent evolution” in favor of intelligent design.

This article was originally published in 2015.

Abdul J. Gaspar