Turtles can act like chameleons to deceive predators and prey alike

In a new research, scientists have determined that turtles can act like chameleons, by matching the colour of their skin and shells to the colour of their habitat's substrate, which helps them to deceive predators and prey alike.

According to a report in Natural History Magazine, the research was carried out by John W Rowe, of Alma College in Michigan, US, and his three colleagues.

They collected gravid female midland painted turtles and red-eared sliders from the wild, brought them to the lab, and injected them with oxytocin, a hormone that induces egg laying.

They assigned the hatchlings to two control groups, which they kept for 160 days on either a white or a black substrate, and to two "reversal" groups, which they kept for 80 days on white or black and then switched to a substrate of the opposite colour for another 80 days.

The researchers periodically used a spectrometer to measure the colour intensity of spots on each turtle's carapace and head.

By day 80, all the turtles had lightened or darkened, approaching the colour of the substrates they were living on.

By day 160, the controls were staying the course, but both reversal groups had switched and were now well on their way to the colour intensity of their new substrate, confirming that turtles can completely reverse melanisation.

That puts freshwater turtles in the same league as chameleons and squid, even if their melanisation process is, true to form, much slower.