Ask Mr Brain...all will be explained

PUBLISHED : Friday, 02 April, 1999, 12:00am
UPDATED : Friday, 02 April, 1999, 12:00am

How can everybody on Earth have different fingerprints? EMILY Shung Tak Catholic English College Our fingerprints are unique to each of us, even identical twins have different fingerprints. While identical twins look very similar, there are slight differences between them. Although they have the same genetic code, they develop slightly differently in their mother's womb, with one having a better blood supply.

At birth, one twin is always bigger than the other. Given these slight variations, identical twins develop different, though similar, finger prints. So, if even individuals who have identical genes have different fingerprints, it's not surprising that the rest of us all have our own unique fingerprints. Even chimpanzees have different fingerprints.

In the late 19th century, realising that every individual had unique fingerprints, several scientists began developing systems to classify and identify them. With this development, the days of the carefree criminal were numbered.

Can elephants swim? Surprisingly, the world's largest land animals are excellent swim mers. Elephants even have built-in snorkels. As they submerge themselves, they leave only the nostrils at the tips of their trunks above water. In this manner, elephants can swim for several kilometres.

According to one researcher, they have been known to cover up to 48 kilometres at a speed of 2.7 kilometres per hour. Scientists have even observed elephants swimming to islands in lakes or in the sea - perhaps the pachyderm's version of a holiday resort.

What are skunks? Why do they stink? Skunks are small mammals belonging to the weasel family and well- known for their smelly secretions, which can be ejected forcibly from the anal glands towards an attacker.

In addition to its strong smell, the secretion has irritant properties and is an effective deterrent to would-be predators.

There are 13 species of skunks, all of which have bold black and white patterns in their fur, which are clearly warning signals. The commonest species is the striped skunk, whose range extends from Canada to Mexico. The closely related hood ed skunk is limited to the southern United States and Central America.

How did the phrase 'dead as a doornail' come about? There are a few theories as to the origin of the phrase. One English language authority suggests the ancient doornail was a stud against which the door-knocker struck. Perhaps, as another theorises, some obscure character once quipped that the knocker had struck the nail on the head so often that it must be dead.

Then there is the idea that since regular nails never have been used to build doors, the phrase 'dead as a doornail' originally implied that one was as dead as something that never existed.

None of these theories can be proven.