57 Hybrid Sharks Found
Australian scientists report something they have never found in the wild - hybrid sharks. Two species of blacktip shark have not only produced hybrids, but are producing a lot of them - 57 caught and identified so far. The fraternization may be due to a depleted habitat with fewer blacktips of each species, or to a change in one species' range, but either way it's a surprise to icthyologists. The classic definition of a species is a population that breeds only with its own kind. While that's pretty elastic, the rule is that different species mate only under unusual conditions. In a picture of evolution in action - possibly giving rise eventually to a new species - the unusual is becoming common.