Turtles Produce Mucus-Like Substance to Delay Egg-Laying

Turtles delay laying their eggs until they find a safe environment, reveals a new study.

Female turtles are choosy about where they lay their eggs, as they need to ensure that the environmental conditions are safe and ample food resources are available for their offspring.  

"After an egg is laid, the membrane inside the egg connects and so the egg can't be turned at all or the young will die," study researcher Anthony Rafferty, of Australia's Monash University, said in a statement.

"We think she wants to stop the development of the egg before it reaches that stage because if she was laying the egg, and it turned at all during the laying, it would die if it were at any further stage of development."

Rafferty and his colleagues have found that the turtles delay laying their eggs by producing a mucus-like substance, which creates low oxygen levels in their reproductive tracts, reports LiveScience.

For their study, the research team examined eggs and oviduct secretions from four species of turtles, including the green sea turtle (Chelonia mydas) collected from Australia. They found that the pregnant turtles produce the mucus-like substance inside the reproductive tracts where the eggs are stored. This substance reduced oxygen supply to the eggs, which halted the embryos' development at a certain stage.

But the eggs that were kept at desirable conditions with plenty of oxygen supply continued to grow normally, said the researchers.

The findings might explain why turtles don't give birth to live young ones. There are several species of lizards and snakes that give live births, by holding on to their eggs for extended periods and allowing them to develop inside the mother.

Researchers hope the study could help conservationists in their efforts to conserve endangered turtles like the leatherback turtles that often fail to hatch.

The findings of the study are published in The American Naturalist journal.