Justin Marshall of the University of Queensland in Brisbane, Australia, has done the unthinkable. He has taught mantis shrimps to distinguish between cubes painted with different polarisation patterns. The human eye cannot detect the orientation of polarised light. There is more to the colourful displays of these shrimps than meets the eye, say biologists who have found that the animals can see this light. The shrimps are the first crustaceans known to have polarised vision. The researcher also found that their bodies carry polarisation patterns that should appear striking to fellow mantis shrimps. "These are mostly used while displaying threat or soliciting mates,' says Marshall ( Current Biology , Vol 9, p755).