Is your pet hamster high on life -- or just a sad little ball of fur?

A new study from England suggests that -- just like humans -- some hamsters can have a shift in mood, from a gloomy demeanor to a more rosy view of life, for instance. What's more, the research shows that it doesn't take a whole lot to boost a hamster's mood: some hammocks to lounge in, a bit of extra bedding, and a chew toy or two can make a big difference. (1)

Trying to understand if someone else is happy.

Trying to see in his/ her/ its brain.

Trying to read minds.

Impossible.

Unless we all share the same…