Leatherback turtles are the largest turtle in the world, as well as one of the most remarkable.
For example, if the temperature in their eggs gets below 25.5° Celsius, the hatchlings will be male. If the temperatures rise above that, the hatchlings will be female.
Also, leatherbacks are named for their shell, which isn’t hard like other turtle’s. It’s smooth, like leather. Hence leatherback sea turtle.
Leatherbacks are endangered. There are an estimated 60,000 left in the wild, which actually isn’t a lot.