The Cincinnati Zoo & Botanical Garden

Armadillos are famous for their defensive, armored shells.
The three-banded armadillo can actually roll itself
completely into a ball. Often it will leave its shell open just
enough for a would-be predator’s nose or paw to poke
through. Suddenly the armadillo slams shut its shell,
clamping down tightly and causing injury to the intruder,
which is generally enough to send a predator packing.