Skip to Content

Why Do Plants Have Thorns?

If you have ever felt the spiky thorn of cactus or a hawthorn, then you know that these can be very sharp and very painful. In this article, I wanted to give a quick overview of the reasons that plants have thorns.

Plants with thorns are an excellent deterrent to any animal that wants to eat them. Thorns come in all sizes and shapes, but they all serve the same purpose. As the thorns are so sharp, most animals will not come close to them and would not think about trying to eat them.

Although we think of the different sharp appendages on cactus, roses, and hawthorns as thorns, these are actually quite different. Cactus have spines, and these are a type of leaf. Roses have a prickle on the stem, which grows from the outer skin. Thistles also have prickles, while hawthorns, as the name suggests, have true thorns.


The roses’ prickles are quite easy to remove from the plant, as they are only attached to the surface. However, the cactus spines and the thorns on the hawthorn bush are more difficult to break off. This is because they are attached to the structure of the plant.

Although these plants are harder to eat and provide a good defense, some animals still feed on plants with thorns. Donkeys will eat thistles without any problems, while giraffes and camels will use their long tongues to get in between the spines to get to the leaves.

Not many animals feed on plants with thorns, spines, or prickles, showing us that this method of defense works.

If you want to know why plants turn towards the sun, you can find out in this article I wrote