Crying in response to emotional distress has been documented only in humans. However, many animals, particularly the young, demonstrate their response to distress by changes in vocalizations and movement. For example, many of us have heard a newborn kitten calling for its mother, or a hatchling bird calling to its parent when it wants food. Whether these are actual “crying babies” is a matter of interpretation—they may be calls for food or warmth. While tear production (the lacrimal response) is found in a number of animals (but not crocodiles!), the tears are used to maintain the cleanliness and moisture of the eyes and not to display emotion.