Green Sea Turtle scientific illustration… finally got around to finishing some artwork on my vacation
Green Sea Turtles (Chelonia mydas) erupting from their nest.
Conservation status: Endangered.
Turtle hatchlings use the safety-in-numbers-strategy. Hatchlings wait until the majority of the eggs have hatched, digging up to the surface together and erupting through the sand and heading for the brightest horizon.
With so many predators in their early life stages, the large number of hatchlings ensures that a few will survive to adulthood. Unfortunately with modern day threats, such as by-catch, net entanglement and poaching, affecting adult populations too, all species of sea turtle are listed under some level of threatened by extinction.
This was taken at a hatchery I worked at in Malaysia.
Study finds Loggerhead turtles depend on broader range of habitat than previously thought
A new US Geological Survey study suggests that the threatened loggerhead sea turtle may require broader habitat protection during the nesting season.
"This is the first study to locate and quantify in-water habitat use by female loggerheads in the Northern Gulf of Mexico subpopulation during their reproductive periods," said lead author Kristen Hart, a USGS research ecologist. "Our tracking results show they depend on a much broader range of habitat during this critical part of their lives than was previously thought to be required."
The study reveals detailed loggerhead movements during “inter-nesting” periods, showing patterns that vary for individual turtles. Generally, this period begins when a female returns from open seas around May and lasts roughly until September. Up until now, efforts to protect the species generally centered on beaches with high nesting activity under the assumption that once turtles had nested on those beaches, they either remained in their immediate vicinity or migrated back out to sea.
Satellite data and researchers observations confirm that the loggerheads nest at multiple beaches and sometimes these beaches are hundreds of miles apart.
"These data show it is not sufficient to just protect habitat around high density nesting beaches … because many turtles that nest on the Peninsula use the entire region from the eastern Florida Panhandle to Louisiana," said Lamont.
"We are working towards defining areas where sea turtles concentrate their activities at sea, effectively building a map of in-water turtle hotspots," said Hart. "The more we know about their habitat use, the more questions are raised about their behavior and ability to adapt."
Female Hawksbill turtles are monogamous.
Because "New insight into Hawksbill Turtles’ mating patterns" or "Hawksbill turtles’ monogamous sex life revealed" sounded creepy and overfamiliar.
Dr David S Richardson and Karl Phillips from the University of East Anglia looked at turtle nests on Cousine Island in the Seychelles, an eco-tourism holiday destination favoured by the rich and famous.
Working with the islands’ conservation staff they used a non-harmful procedure to collect DNA from the hard skin of the flipper, or around the shell.
The researchers looked at 43 mothers and 1600 young to reconstruct a genetic model of each nestling’s father, without having to catch the males out at sea. ‘It’s important to do this so that we can understand their mating system and see how much genetic variation there is within the population’ says Richardson.
This is the first comprehensive study into Hawksbill Turtle mating patterns and the findings may help conservationists refocus efforts to where they’re needed.
The scientists were surprised then to find all of the eggs from an individual female are normally fathered by the same male. This means the mothers mate only once and then store the sperm for the entire mating season, fertilising all their eggs with it.
Monogamy in the animal kingdom is the exception rather than the rule. Many females are forced to mate multiple times by aggressive males, or prefer to mate multiply to ensure they have the best quality sperm.
'If they mate with one male and then met another one that was in some way better, bigger or stronger, they might re-mate and have a mix of eggs fertilised by both,' Richardson explains. 'However, it seems female Hawksbills would rather mate just once, far away from their nesting site, then store the sperm, perhaps to avoid unwanted male attention.'
Now the scientists know that not only are there lots of males fathering the nestlings, but there are many male turtles scattered far across the Indian Ocean. Conservationists can use this information to widen their efforts, from the beaches where the females lay their nests to the entire Indian Ocean area, in order to protect males too.
Peek inside a Leatherback Turtle’s (Dermochelys coriacea) mouth: How to eat jelly fish when your mouth is an exquisitely evolved jellyfish deathbed.
We know turtles like to eat jellyfish, and the Leatherback likes them most of all. However, this is the biggest turtle, consuming a prey that extremely low nutritional value, therefore it has to nom on a lot of them. As it does so, it takes in saltwater as well. The jellies and the saltwater get stored in the esophagus.
What happens next you ask? Is it to do with the horrific looking backwards facing spines that don’t look comfortable in anything’s mouth?
But of course! Because that is the beauty of evolution, the refined logic of adaptation.
The muscles of the esophagus squeeze the seawater out of the mouth and the spines, which get progressively larger down the esophagus, hold the jellyfish in place. Once all the water is gone, the jellies are passed into the stomach.
This is one of the many *awesome* characteristics of the leatherback turtle - trawling for jellyfish on this earth for over 90 million year.
Trawling for fish/shrimp (by humans, not leatherbacks), is one of the reasons Leatherbacks are classified as Critically Endangered by the IUCN Red List.
Source: Evolution FB
Via Science Alert
The survival of a Sea Turtle is literally a miracle!
Leatherback Sea Turtle (Dermochelys coriacea)
by National Geo staff
Leatherbacks are the largest turtles on Earth, growing up to 7 ft (2 m) long and exceeding 2,000 lbs (900 kg). These reptilian relics are the only remaining representatives of a family of turtles that traces its evolutionary roots back more than 100 million years. Once prevalent in every ocean except the Arctic and Antarctic, the leatherback population is rapidly declining in many parts of the world.
While all other sea turtles have hard, bony shells, the inky-blue carapace of the leatherback is somewhat flexible and almost rubbery to the touch. Ridges along the carapace help give it a more hydrodynamic structure. Leatherbacks can dive to depths of 4,200 ft (1,280 m)—deeper than any other turtle—and can stay down for up to 85 minutes.
Leatherbacks have the widest global distribution of all reptile species, and possibly of any vertebrate. They can be found in the tropic and temperate waters of the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. Adult leatherbacks also traverse as far north as Canada and Norway and as far south as New Zealand and South America.
Unlike their reptilian relatives, leatherbacks are able to maintain warm body temperatures in cold water by using a unique set of adaptations that allows them to both generate and retain body heat. These adaptations include large body size, changes in swimming activity and blood flow, and a thick layer of fat (click here)…
(read more: National Geo) (photo: Brian Skerry)