OtterKnow Kids Encyclopedia

The barrel cactus is shaped just like a round, prickly ball or a fat barrel, and that is exactly how it got its funny name! It is covered in rows of sharp, curved spines that protect it from hungry animals. Barrel cacti can grow to be about four feet tall, which is probably about as tall as you are.

Inside its round body, the barrel cactus stores lots and lots of water so it can survive in the hot, dry desert for months without any rain. The outside has deep ridges that work like an accordion. When it rains, the cactus soaks up water and the ridges stretch out to hold more, and when it is dry, the ridges squeeze back together.