Report: Dogs are smart

London-When dogs bark, they are sending a unique message, a new study indicates.

Scientists believe that dogs can convey specific messages via the pitchand pace of their barks.

Researchers at the University of California, Davis are leading the study,which was reported in New Scientist magazine.

Dogs usually use high-pitched single barks when separated from theirowners and a lower, harsher "superbark" when strangers approachor the doorbell rings, according to Dr. Sophia Yin, an animal behavioristat the university.

Playful woofs are high-pitched and unevenly spaced.

In addition, scientists from Brazil's Pontifical Catholic Universitysuggest dogs have a counting mechanism that can be observed when givingtreats. Scientists say the animal recognizes when it is being short-changedon treats because it has a basic mathematical ability that enables it totell when one pile of objects is bigger than another.

"But to count, an animal has to recognize that each object in aset corresponds to a single number and that the last number in a sequencerepresents the total number of objects," the report notes.

Dr. Robert Young, lead investigator at Pontifical Catholic Universitytested the theory on 11 mongrels using dog treats.

The dogs were shown treats and then a screen was lowered and the treatswere left untouched or some were added or removed. If a treat was addedor taken away the dogs studied the treats much longer than they did whenthe goodies were not disturbed.