Males were targeted. Females were left untouched. The reason comes down to the thickness of a shell.

Every winter, northern map turtles cluster together to hibernate in the water beneath a frozen lake. Then one year, their resting grounds became a scene of violence.

Cartoons often suggest turtles wear shells like removable armor. Those stories show turtles stepping out, swapping shells, or treating them like clothing. Biology disagrees. A turtle shell is not an ...