Recruitment has also been observed by the African Weaver Ant Oecophylla longinoda for the purpose of communicating new food sources, emigration to new sites, and for defense against intruders.
[4] The ants communicate using a system composed of olfactory or scent clues from several glands together with body movements.
This fascinating mutualistic relationship between people and a wild bird, and the communicative system underlying the partnership, has been studied by anthropologists and ornithologists.
[7][8][9][10] The need to convey information using displacement has been suspected to have been the evolutionary pressure leading to language development in humans, as outlined by Derek Bickerton in Adam's Tongue.
It's only when you fully appreciate what displacement means, how the absence of displacement is not just a casual feature of ACSs but a crucial defining feature of pre-human minds, that you can start getting the complete picture.The unique environmental need selecting for a communication system capable for displacement in humans or their direct ancestors is not identified, but hypotheses include Bickerton's theory of small groups finding large herbivore carcasses, and needing the assistance from other small groups of humans to defend against other dangerous scavengers (large cats, hyenas) competing for the same source of food.