In a new study from The American Naturalist, researchers from the University of Zurich studied vocal communication between fallow deer mothers and their offspring. They found that only adult females have individually distinctive calls, meaning that fawns are able to distinguish their mother's calls from those of other females, but mothers are not able to distinguish between the calls of their own offspring and other fawns. This is in contrast to previous studies and provides a novel insight into parent-offspring recognition mechanisms.
"Newborn fawns lie concealed and silent in vegetation away from their mothers to avoid detection by predators, and mothers return intermittently to feed them," write Marco Torriani, Elisabetta Vannoni, and Alan McElligott. "Vocal communication is very important for ungulate hider species because mothers and offspring rely on contact calls for reunions to occur."
The researchers tested vocal recognition on Swiss fallow deer farms using recordings and playback experiments. Similar research on domestic sheep and reindeer has shown that both mothers and offspring are able to recognize each other based on individually distinctive contact calls. However, reindeer and sheep tend to populate open habitats lacking cover, and the researchers argue that the recognition system employed by deer evolved in habitats providing abundant cover for newborns. While sheep and reindeer are mobile soon after birth - and thus remain in constant close contact with the mother - mother-offspring contact for deer is limited during the first few weeks of life to when nursing occurs.
"Our results show that different environmental conditions influence predator avoidance strategies and also effect the evolution of different parental recognition mechanisms," says McElligott. "This appears to be independent of phylogenesis because although fallow deer and reindeer are more closely related than reindeer and sheep, the mother-offspring recognition system of reindeer and sheep is more similar."
Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles.
Marco V.G. Torriani, Elisabetta Vannoni, and Alan G. McElligott, "Mother-young recognition in an ungulate hider species: a unidirectional process." The American Naturalist 167:9.