Infant Cries Have Universal Appeal
Experiments show animals respond to the cries of infants of many other species, if the pitch is close to that of their own infants' cries.
The sound of a baby crying is hard to ignore, and that's not just true for humans. Dr. Susan Lingle, a biologist at the University of Winnipeg, has found in her studies that mule deer and white tail deer will respond protectively to the distress cries of a whole range of infant animals - not just their own infants. Dr. Lingle and her students found the deer would respond to the cries of any baby animal whose calls were in the same frequency range as their own infants. They also found that if they shifted the pitch of cries that weren't initially in the same frequency range, the deer would respond to those cries as well. Among the infant cries of animals they tested were human, goat, marmot, antelope and even fur seal. This suggests that the structure of an infant distress call is deeply ingrained in at least mammal species, even in those separated by tens of millions of years of evolutionary change.