Akis is a Greek word for thorn. Most of the 1,300 species of acacia protect themselves from giraffes and other herbivores with their long thorns. In addition, many acacias produce toxic compounds when their leaves are damaged. They can also warn nearby acacias by emitting ethylene from their leaves. 

Certain acacia species form a mutually beneficial symbiotic relationship with ants. Acacias provide ants with a sweet liquid to drink and a place to live inside their hollow, swollen thorns. The bite of ants defending their habitat is very painful, which is why giraffes or other herbivores will quickly move on to another target. 

The sap of some acacias is used to make gum arabic, which is used in the manufacture of sweets and medicinal tablets. For example, almost half of Sisu pastilles are made from gum arabic.