Why instead of leaves have thorns?
To defend themselves from animals that want to bite them to drink the water they have inside, and especially in the case of those who have piles of fine and white thorns, to protect themselves from the sun and thus maintain their good temperature and not dehydrate.
They can hold up to two years without water…
But you have to water them! Keep in mind that they grow in places with adverse climatic conditions: periods of drought and times of great rainfall. If we take it to the domestic field, the translation would be: to throw a lot of water but very few times.