Tall tails: Pet myths busted

Dogs wag their tails because they’re happy to see you This is not the only reason dogs wag their tails. Sometimes they do it when they’re frightened or apprehensive. Tail-wagging is a generic emotional response that should be judged in the context of the dog’s overall behaviour. If it’s also biting you, it probably isn’t that happy to see you. Photograph: Elliott Erwitt/©Elliott Erwitt / Magnum Photograph: Elliott Erwitt/guardian.co.uk Guinea pigs eat their young It’s possible, but extremely uncommon. Guinea pigs are vegetarians. They do eat their own droppings, which might be enough to put you off. Photograph: Dan Burn-Forti/Guardian Photograph: Dan Burn-Forti/guardian.co.uk Your cat hates your baby and wants to kill it There can’t be many people who still believe that cats deliberately suffocate babies by sucking the breath out of them, but in case you’re one of them, they don’t. That doesn’t mean a sleeping cat couldn’t accidentally suffocate a newborn baby (there are a few documented cases), so it makes sense to keep the cat out of the baby’s room for the first couple of months. Photograph: Paul Kaye/Corbis Photograph: Paul Kaye/guardian.co.uk Rabbits should eat plenty of carrots Carrots are too high in sugar for rabbits to ingest on a regular basis, and they are better off eating the green tops. Bugs Bunny has a lot to answer for. Photograph: Dan Burn-Forti/Guardian Photograph: Dan Burn-Forti/guardian.co.uk Dogs can only see in black and white Actually they see in colour, but not very well. They’re red-green colour blind, though they can easily distinguish blue. Photograph: Alessandro Rizzi/Gallery Stock Photograph: Alessandro Rizzi/guardian.co.uk Cats purr when they are happy True, but they also purr when they’re in pain, and when they’re dying. Photograph: Gabor Geissler/Getty Images Photograph: Gabor Geissler/guardian.co.uk One dog year is equivalent to seven human years There are certain advantages to this persistent myth (it helps a lot of children learn their seven times table), but it’s obviously a bit simplistic and depends on the breed. Dogs mature much faster than humans – a two-year-old dog is roughly equivalent to a 21-year-old person – but things slow down after that; a 10-year-old dog is, in general terms, closer to 50 in human years than 70. Photograph: Kyoko Hamada/Gallery Stock Photograph: Kyoko Hamada/guardian.co.uk Putting a bell on your cat will stop it killing birds Apparently a lot of cats actually get better at hunting prey after you bell them, because they have to learn to stalk without letting the bell make any noise. Photograph: Corbis Photograph: guardian.co.uk A hamster in a wheel can run six miles in a single night This one is true, apparently. Whether the hamster feels it has accomplished anything in the morning is another matter. Photograph: Dan Burn-Forti/Guardian Photograph: Dan Burn-Forti/guardian.co.uk Cats have nine lives It’s unlikely anyone ever actually believed this since it’s so easy to disprove through experimentation. It’s not universal (in Turkish and Arabic traditions cats only get six lives) but it is old; there are references to the nine lives of cats in Shakespeare. The notion probably stems from the fact that cats tend to survive things you and I wouldn’t, particularly falls from great height. Photograph: Chloe Sells/Gallery Stock Photograph: Chloe Sells/guardian.co.uk