Several plants in tropical forests form mutually beneficial partnerships with ants. These relationships are called symbioses or mutualisms.
The most famous ant plant is the Bull Thorn Acacia, Acacia sphaerocephala. This mimosa relative has large, hollow thorns borne in pairs on the trunk and branches, and produces special protein bodies on its leaves. In the wild, a species of slender, stinging ants use the thorns as living quarters and eat the food bodies. In return for this cozy shelter and abundant food, the ants fiercely defend their host plant from anything – plant or animal – that touches it.