Oct. 13, 2010 -- The idiom “a dog’s life” suggests that pooches
have it made when it comes to happiness, but new research
indicates that the emotional states of dogs can be as varied as
the moods of their owners. Dogs can see their food bowls as half
empty rather than half full, just as human pessimists see a
glass of water as half empty instead of half full. British
researchers who tested separation reactions of dogs say they
found that some dogs are more likely than others to become
depressed and anxious when left alone, causing them to bark,
scratch at doors, chew on furniture, and generally misbehave. On
the other hand, optimistic dogs are more likely to behave better
and become more relaxed when left alone. Mike Mendl, PhD, head
of animal welfare and behavioral research at the University of
Bristol, and colleagues, studied 24 dogs, males and females,
that had been sent to two animal centers. Each dog was tested
beforehand for separation anxiety-related behaviors. A
researcher played with each dog in an i