Deer and seals aren't exactly neighbors, so why would a mother deer look for a baby in distress after hearing a fur seal's cry? Biologists Susan Lingle of the University of Winnipeg and Tobias Riede of Midwestern University conducted an experiment in which they used recordings of other species' infant cries and discovered that mamas respond - even if it isn't their baby crying, according to Scientific American.
During the course of two summers, Lingle and Riede played recordings of various infant mammals - elands, marmots, bats, fur seals, sea lions, domestic cats, dogs and humans - to herds of mule deer and white-tailed deer. They discovered that if the basic frequency of the cry was comparable to the cry of a baby deer, the mother deer would respond with concern.
The mother deer were not concerned when they heard white noise, birdcalls or coyote barks.
"As humans, we often 'feel' for the cry of young animals," Lingle said, according to Scientific American. That is, if the animal's cry is similar to the cries of our own offspring.
Lingle and Riede's findings were published in American Naturalist in October.
Psychologist David Reby of the University of Sussex in England studies the progression of communication and says it is to the infants' advantage to call any potential caregiver in order to increase the opportunity for survival, according to Scientific American.
And for the parents, "it is probably more advantageous to respond to anything that vaguely resembles a baby distress call," Reby said, according to Scientific American. Parents need to react without deciding if it is their baby in danger, because any hesitation could have deadly consequences for their offspring.
These findings could shed some light on cross-species adoption, especially if a mother recently suffered the loss of her infant and her maternal hormones are still present.
