Washington: Some animals weep out of sorrow or stress, similar to human baby cries, according to animal behaviour experts.
The question whether animals are capable of crying emotionally has been raised again after media reports last week described a crying newborn elephant calf at Shendiaoshan Wild Animal Nature Reserve in eastern China.
The calf reportedly cried inconsolably for five hours after being stomped on by his mother.
"Some mammals may cry due to loss of contact comfort," said animal behaviourist Marc Bekoff.
"It could be a hard-wired response to not feeling touch," added Bekoff, former professor of ecology and evolutionary biology at the University of Colorado, Boulder.
For elephant calves and human infants, crying is probably more out of stress than sorrow, he said.
He pointed out that scientific studies have proven that chicken, mice and rats display empathy - feeling another`s pain - which is an even more complex phenomenon.
For crying, the animal would have to be of a social nature, possess eye anatomy similar to ours, and have brain structure for processing emotions.
Dogs are among the most social animals, but scientists and owners have yet to report on a depressed dog crying its eyes out.
"However, dogs and other animals certainly can suffer and may recognise suffering in others," said Brian Hare, an associate professor of evolutionary anthropology at Duke University who co-founded a dog analysis tool "Dognition".
In a questionnaire on the Dognition site, 72 per cent of owners reported that their dog suffers from mild to extreme separation anxiety, likely similar to what the elephant calf felt.
"This anxiety is manifested as whimpering, whining and howling when the dog is separated from a loved one. So dogs may not cry with tears, but they certainly can cry with vocalisations to say they are anxious, stressed or lonely," Hare said.