Did every prehistoric animal eventually die out?
   Gabrielle, 11, Manchester-by-the-Sea, Massachusetts

Dr. dig responds:
Prehistory means the time before writing, so the prehistoric period is a really long one that ended at different times at different places. In Egypt, it ended in approximately 3000 b.c., with the invention of hieroglyphs. In Britain, it ended in 55 b.c., when the Romans invaded and brought writing with them. In North America, it ended with the arrival of the first Europeans who spread writing as they settled during the 16th century a.d. Some peoples in Africa and Australia were living a prehistoric life as recently as 100 years ago. So, as you can see, in some parts of the world, prehistory is not too distant past, and the animals haven't changed too much. If we go much further back in time‹to the Ice Age more than 10,000 years ago‹we find many animals we would recognize but a few, such as mammoths and sabre-toothed tigers, that have now vanished. Further back again, to the age of the dinosaurs, the animals pretty much all look strange. But the insects, our planet's most successful animals, are the direct ancestors of the insects that fly around today.