The shell itself is made from broadened and flattened ribs, fused to parts of the turtle’s backbone (so that unlike in cartoons, you couldn’t pull a turtle out of its shell).

This wrinkled ol' pal, found across much of the U. S., may be in decline. A huge study in North Carolina plans to track box turtles for 100 years, to learn how to best protect them.

Odontochelys was a turtle in a half-shell, whose armour had a lower half (a plastron) but not a top one (a carapace). Its discoverers suggested that it was a sign that turtles evolved via a ...