THE PARADOXICAL FROG

The world is full of intriguing paradoxes. Does this article still exist when you're not reading it? If I travelled back in time and killed my grandfather, would I still be writing this now? And how can two socks go into the washing machine, but only one sock comes out? Perhaps the biggest paradox, however, is how can a frog get smaller as it grows up?

- DR HELEN PILCHER

Life starts, pretty much as expected for the paradoxical frog (Pseudis paradoxa). The female lays fertilised eggs in the lakes and lagoons of South America and Trinidad. Eggs hatch, tadpoles emerge and then start to eat. The voracious larvae feed mostly on algae and very soon, start to bulk up. They start small, like other tadpoles, and grow at a similar rate to their non-paradoxical cousins.

If the conditions are right, however, the tadpoles just keep on growing. Bigger than a blueberry. Bigger than a strawberry. Bigger even than a plum. Think 'satsuma stuffed inside an ankle sock,' and you're approaching the right dimensions ... and you've found your missing sock.