Just as adult turtles warm themselves in the midday Sun, turtle embryos 'bask' in their eggs by cosying up to the Sun-warmed side.
Wei-Guo Du at the Chinese Academy of Sciences in Beijing and his colleagues shone light through the freshly laid eggs of softshell turtles (Pelodiscus sinensis) to mark the positions of the embryos inside. The team then incubated the eggs, warming them either from above or from one side. Over a period of days, embryos made their way to the warmest part of the egg (pictured: heat from above, left; from the left, right), which could differ from the coolest part by almost 1 °C. If the heat source shifted, the embryos followed.
Greater exposure of the embryos to heat could modify traits such as body size and sex, and hasten hatching to reduce nest predation.
About this article
Cite this article
Turtle embryos seek sunny side. Nature 474, 9 (2011). https://doi.org/10.1038/474009c