Science: Update

CARNIVORES ARE OF two types: those that eat animals their own size, and those that go for the "canapes" of the animal world, say researchers at the Zoological Society in London.

A study published in this week's Nature by Chris Carbonne and colleagues shows that smaller predators - such as foxes, bats and badgers - weighing less than 21.5kg (the weight of a human toddler) usually dine on creatures weighing less than 45 per cent of their own body weight. Carnivores bigger than 21.5kg (such as lions) have to go for much larger meals to stay alive because of their different energy requirements. The scientists believe that, in ecological terms, larger carnivores are a distinct group and not simply a scaled-up version of smaller meat-eaters.

THE SITE where Alexander Fleming discovered penicillin has been awarded an International Historic Chemical Landmark by the American Chemical Society.

Fleming discovered antibiotics almost by accident when he returned to his laboratory at St Mary's Hospital in London after a holiday. He found that bacterial colonies growing on some old lab dishes had failed to grow around the mould Penicillium notatum. The award is only the second to be given in Britain.

THE MARS Polar Lander spacecraft has had a narrow escape: engineers discovered a flaw in its design, less than a month before it is due to touch down on Mars. A team at Nasa, investigating the mix-up that led the Mars Climate Orbiter to crash, noticed that a serious error in the thrusters for the Lander could have caused its fuel to freeze in space. The problem is now solved, reports New Scientist magazine. Nasa says: "We will turn on the [fuel] heaters earlier."

THE UKRAINIAN security service has accused four marine biologists of "exporting state secrets" - puzzling their Western colleagues. New Scientist suggests the biologists fell under suspicion because they study light- emitting plankton. These can reveal the presence of submarines because they glow when they are moved, for example by a passing vessel.

Europe has funded studies into plankton - including bioluminescent species - in which the Ukrainian scientists took part. Publication may have led directly to their interrogations and searching of their homes.

In last week's article on prions, the work by David Brown of Cambridge was in fact a collaboration with Boon Seng Wong and Ian Jones of the Institute of Virology, Oxford University