Images Dated 15th April 2004

Humpback whales exhaling

Humpback whales exhaling in calm waters off the Antarctic Peninsula. When a humpback whale (Megaptera novaeangliae) exhales, air is released from the whale's blowhole, the nostril on the top of its head. The humpback whale may reach a length of 15 metres and weigh up to 27 tonnes. It is known for the impressive leaps that it makes out of the water and for its long vocalisations, which are more elaborate than in any other known whale song. Humpback whales are found in the deep waters of the coastal regions of all the world's oceans. They are one of the whale species most threatened with extinction

© DAVID VAUGHAN/SCIENCE PHOTO LIBRARY

Basking Weddell seal

Weddell seal (Leptonychotes weddelli) basking in the summer sun near the Antarctic Peninsula. Weddell seals are found near the fast ice of the Antarctic continent and some nearby islands. They grow to a length of 3 metres and can weigh up to 450 kilograms. The females are usually bigger than the males. Weddell seals remain under the ice during the winter months, and breath through holes they create in the ice with their teeth. They have well-developed eyesight that allows them to locate the breathing holes in low visibility. Their eyesight also allows them to feed in low light conditions and they use their whiskers to assist in finding food

© DAVID VAUGHAN/SCIENCE PHOTO LIBRARY

Mummified foot resting on DNA autoradiograms

Mummy's foot. Close-up of the foot of an Egyptian mummy on autoradiograms. The autoradiograms are X- ray prints made from DNA extracted from the foot. DNA (deoxyribonucleic acid) is the molecule responsible for carrying the genetic code. It holds the code as a series of pairs of bases along the length of the molecule. The dark bands on the autoradiogram represent the positions of specific bases in the DNA, and thus the genetic code. This "DNA fingerprint" is different for every individual, and familial traits can be traced by studying it. Taking DNA from preserved humans gives a good account of how humans spread across the world from the point of their evolution

© VOLKER STEGER/SCIENCE PHOTO LIBRARY