Mary Carde, Cherrybrook He's waiting for the queen to give him some heirs.

Arthur Grey, Wentworth Falls What causes the headache you get when you eat ice-cream too fast? Ice-cream headache is caused by "crossed wiring" or "convergence" in the sensory system of the head. Cold liquids, solids or gases passing over the palate and pharynx stimulate cold receptors there and these send nerve messages to the brain. In the brain, some of these incoming messages inadvertently junction with brain cells that also receive signals from parts of the head that help process the sensation of headache. This fools the brain cells - and hence the ice-cream eater - into thinking a headache is occurring. Ice-cream headache is much more common and intense in people who have an underlying headache disorder such as migraine. This suggests that both ice-cream headache and migraine are at least partly the result of "wiring defects" or an oversensitive sensory alarm system.

Dr Geoff Lambert, Headache Research Laboratory, University of NSW The dentist's bill for the filling.

Nathan Smith, Bondi Have there been any documented or anecdotal cases of death from overdoses of wasabi, chilli or other hot spices? Very improbable. After ingestion just be sure to eat lots of ice-icream as an antidote. Later, when you're in a private, seated position, you'll be so glad you had ice-cream for dessert.

Ken Rose, Chatswood I recall hearing about a US Marine Corps cadet who was forced to drink a bottle of tabasco sauce during "hazing" (what the Americans call bastardisation) and died.

Julian Mallett, Hughes ACT Why don't dogs have belly buttons? They do. Like all mammals, dogs are viviparous; they give birth to live young. When the pup is born the umbilical cord is bitten through by the mother and the remains wither away and fall off, leaving a belly button. The mother licks her pups regularly; saliva promotes healing and in most puppies the hole heals cleanly. It is not always easy to see the belly button in an adult dog and admittedly, dog belly buttons don't look quite like the human version, being basically an elongated scar, often hidden by hair, located just astern of the rib cage.

David Buley, Seaforth Why do people raise their arms above their heads in victory?

Their sweat has a triumphal scent (it's a little-known scientific fact) and it depresses the opponents even more as it evaporates. The invention of deodorant, however, has made this action obsolete - but the motion and purpose behind it is embedded in the human subconscious. Catherine Mah, Chatswood Any answers

- Why do you sometimes feel more energetic and awake the day after a late night than you have all week after eight hours' sleep a night? - Why is the image of the unshaven male so popular in advertising but deemed unattractive and sloppy in daily life?

- Who was Simon, and why do we have to do what he says? - Where is the Universe? - What is the origin of "tickled pink"?

- What and where are the living daylights that people threaten to punch out of you? - Who determines whether races are run clockwise or anti-clockwise?

READERS' RESPONSES: Email your answers, or any questions you want answered, to bigquestions@ smh.com.au or write to Big Questions, Spectrum, SMH, GPO Box 506, Sydney 2001. Limit questions to one short sentence and answers to a maximum of 130 words, and state your name and suburb/town.