大象传媒

The Lake District has clear air and clear water where the rivers begin. Bill Oddie searches a stream bed by turning over stones and eventually finds what he's looking for - a male white-clawed crayfish. It has big claws, so Bill handles it gingerly. It uses the claws for fighting other males, much like a stag's antlers. Crayfish come out at night to feed so is fairly dozy in the daylight. The white-clawed crayfish is a genuine British species and is very rare these days, because interlopers from Turkey and America have been introduced to the UK. The foreign crayfish were introduced because they were resistant to crayfish plague - but unfortunately ended up spreading it to the native crayfish. It's only up here in these isolated areas where no foreigners have arrived and the water is clear and cold, that the natives survive. Bill returns the crayfish to the stream.