Are animals happier than humans? Science suggests that they feel similar emotions to us. But thinkers are divided on whether their feelings are stronger, weaker or the same.
Kangaroo playing air guitar wins top prize
Guitar hero: Perth’s Jason Moore captured a would-be Jimi Hendrix of the kangaroo world. Glossary
Gannets - A large seabird with mainly white plumage.
Aesop - Ancient Greek writer (c.620 – 564BC) credited with hundreds of fables: short stories telling a moral lesson, often featuring animals.
George Orwell - Real name Eric Arthur Blair, a world-renowned 20th-century novelist, most famous for his political novels Animal Farm and 1984.
Stalinism - The ideologies and policies adopted by Stalin.
Parakeets - A small parrot with green plumage.
Annihilation - Complete destruction.