With the exception of sperm whales' off-centre blow-holes and some crabs' single large claw, all complex organisms I can think of are effectively symmetrical along one plane of their body. What is the least symmetrical organism?

Max Maguire, By email, no address supplied

We constantly read about autism rates, schizophrenia rates, depression etc in the human world. And many of us think we can identify stress or depression in zoo animals, or even our pets on occasion. But have there ever been any studies into serious mental illnesses in animals?

What would happen to a chimapnzee suffering from schizophrenia in the wild? Are these just human diseases or is it likely monkeys, horses, cows, hedgehogs etc also suffer from psychoses or neuroses?

Excluding any food that we throw away why do no other animal cook their food.

Last week, I helped a blind guy cross the road and while we were crossing the road I asked him if blind people can hallucinate and have dreams. He said "Of course we can". I researched this and it turns out that blind people can in fact hallucinate.

This got me thinking. I was wondering if it is possible that we are all blind and we are all hallucinating the same things?

Why do you no longer see white dog poo as you did in the 70's?

Do horses get jet lag? I was wondering how, say, the horses involved in the Beijing Olympic events like showjumping and dressage that are flown in for the event, coped with it or whether they don't suffer as much if they don't have the same concept of time as humans.

If cats are colourblind, as they are, and we only see the reflection of things in water, then how do cats see water?

During a recent infestation of headlice among my children, I noticed that the critters lay more eggs on the left side of my children's heads than the right. Most of my children are left-handed so it seems unlikely that this is because my children are more effectively removing the ones on the right hand side by scratching. One hypothesis is that headlice have adapted to humans' tendency to righthandedness by preferring to lay their eggs on the left side of the head.