Painted Turtle

• GeneralIts hatchlings can survive partly frozen in the nest through the winter.
• It has no sex chromosomes: sex is decided by the temperature of the nest. Below about 27 °C males hatch, and above about 30, females.
• That makes it vulnerable to warming: warmer nests produce clutches increasingly skewed towards females, and above 34 °C deformities appear in the plates of the shell.
• It survives the winter without breathing. Adults spend months at the bottom of frozen ponds in complete anoxia, and at 3 °C they can last up to 170 days without oxygen: they neutralise the lactic acid by dissolving carbonate from their own shell and skeleton.
• The hatchlings do something different: they do not go down to the water but spend their first winter inside the nest, buried and enduring temperatures below zero.
• It is the most widespread freshwater turtle in North America, and its genome was the first sequenced from a vertebrate with temperature-dependent sex determination.

Skeleton type

Vertebrate - internal bony skeleton with a shell of bony plates fused to the ribs (reptile)

Habitat & environment

Ponds, lakes and slow rivers with soft bottoms

Sexual maturity

7.5 years

Gestation / incubation

The eggs incubate for between 72 and 80 days

Litter / clutch size

From 4 to 15 eggs per clutch

Sources consulted: https://es.wikipedia.org/wiki/Chrysemys_picta