Mad as a Marine Biologist

High-res 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. Read more. By Harriet Jarlett | Planet Earth Online

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.

Read more.

By Harriet Jarlett | Planet Earth Online

High-res rhamphotheca: 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)

rhamphotheca:

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)