Ever had a fight with a cactus and lived to talk about it? I've had a Cactus thorn stuck in the back of my thigh and one in my thumb that I couldn't get out for over a month!
So why do cactus have thorns? Technically known as spines, they are modified leaves that:
Prevent the plant from losing water by reducing air flow around the cactus
Collect water from morning dew
Give the plant shade to help it keep cool
Protect the plant from pesky, hungry animals (and curious humans)
