Monday, January 16, 2012

Turtle Embryos Can Communicate Across Eggs

River Murray Turtle embryos from South Australia,  can adjust their developmental rate so that all the eggs in a clutch can hatch around the same time, a new study has found. Young turtles face many challenges when they hatch and venture into the world.

Please see Ridley Kemp sea turtles hatching and making way for the sea in video below.)

Hatchlings, as a large group, work together to dig their way out of the nest more easily. And their arrival all at the same time increases their survival chances, as predators are swamped by high numbers of prey. 

Scientists investigated incubation and group hatching in the River Murray Turtle. Although the temperature of the nest affects the developmental rate of eggs, researchers discovered another factor that influences their growth rate ― embryo to embryo communication.

"Turtle embryos are somehow communicating their developmental rates to each other so that they can emerge as a group," said Ricky-John Spencer, zoologist from the University of Western Sydney, and co-author of the study published in Proceedings of the Royal Society today.
Importance of temperature for the embryo.

River Murray Turtles lay large numbers of eggs (up to 30 in one clutch). Eggs near the top of the nest are exposed to warmer temperatures and develop faster than those in the bottom layers. Surprisingly though, all the eggs still hatch at a similar time.

Researchers found that River Murray Turtle eggs in the cooler patches of the nest can adjust their metabolic rates and increase their development, allowing them to catch up to their more advanced siblings.

Baby loggerhead sea turtle photo
In the nest there is some type of signalling between the unborn siblings that enables all eggs to develop fully and hatch together, regardless of the temperature differences. Scientists suspect that carbon dioxide levels or heart rates may be cues for increased metabolism, but further studies are needed to investigate these factors.


  1. Very interesting but weird, in a "stranger than fiction" sort of way. I wonder if the development occurs at more or less the same rate within a temperature range---say five degrees of variation between the bottom and top of the nest. I can see this series of posts developing into a book on the whole life cycle. Well done, Nancy.

  2. Nancy,
    This video is so exciting and amazing. Witnessing a birth is always an awesome experience. I think more of these hatchling made it to the water because the people around scared off the birds.

  3. Thanks for your ever thoughtful comment, Bill. I agree, it is very strange but amazing at the same time...The other thing I know about this kind of occurrence is that the gender of the turtle is determined by placement in the nest, and again, that's due to the temperature fluxuation.

  4. wow that is great do they ever tag any of them for the purpose to follow the breeding season the are cute and hope they can do more to help them

  5. That is a great question! It may be that they're too tiny after just hatching to do the tagging. Also, even with human help in getting lots of them safely into the sea, many don't make it to adulthood. That may be another reason why they seem to only tag adults. Thanks for the comment!