Dear Enemy Effect
Reduced aggression between established territorial neighbors relative to strangers
Territorial animals defend resources needed for survival and reproduction. Animals advertise their ownership of territories through conspicuous signals; birds and frogs vocalize, mammals and salamanders scent mark, lizards display colorful patterns, and fiddler crabs wave their oversized claws in the air. If advertisement is not enough, animals may have to fight off intruders to maintain territory ownership. However, animal fights are relatively rare, even when territories are spatially clumped resulting in frequent interactions between neighbors. Once territories are established, individuals in neighboring territories typically respect territorial boundaries and withhold aggression from their neighbors. This makes sense because aggression can be costly, and if a neighbor already has a territory, they might not...
- Fisher, J. (1954). Evolution and bird sociality. In J. Huxley, A. C. Hardy, & E. B. Ford (Eds.), Evolution as a process (pp. 71–83). London: Allen & Unwin.Google Scholar
- Stoddard, P. K. (1996). Vocal recognition of neighbors by territorial passerines. In D. E. Kroodsma & E. H. Miller (Eds.), Ecology and evolution of acoustic communication in birds (pp. 356–334). Ithaca: Cornell University Press.Google Scholar
- Wilson, E. O. (1975). Sociobiology: The new synthesis. Cambridge, MA: Harvard University Press.Google Scholar