The spines of cacti are actually modified leaves. It helps to imagine cacti as large stems with spines for leaves. One of the main functions of spines is fairly obvious – they protect cacti from predators. ... A surprising function of cacti spines is to provide shade for the cactus itself.

Do cacti have spikes or spines?

Why do cacti have spines? Spines help cacti to thrive in desert environments by providing multiple functions. They protect the plant from predators, provide shade, help regulate temperature, reduce water loss and even help the plant to spread and reproduce.

Why do cacti have spines?

Over time, those leaves evolved into the spiky spines we see on cactuses today because they help the plants survive in hot, dry environments. "They can be a defense mechanism to discourage herbivores - animals that eat plants - from eating the cactus. But, also, spines create shade!" explains Kimberlie McCue.