Mantis shrimp

The mantis shrimp is a small, brightly coloured sea creature that is neither a mantis nor a shrimp. It hunts by punching. Its club-shaped front limbs strike with an acceleration similar to a small-calibre bullet, fast enough to smash snail shells and, on occasion, to crack the glass of an aquarium. It is the only animal on the reef that has to be housed like a boxer.^[1]

The punch

The punch moves so fast that the water in front of it boils for an instant, forming tiny bubbles that collapse with a flash of light and heat. So each strike hits twice: once with the club, and once with the collapsing bubble. Physicists regard this as an unfair advantage and have been asking the mantis shrimp to pick one.^[2]

The water recovers immediately and is not believed to hold a grudge.

Eyes

Humans have three types of colour receptor in their eyes. The mantis shrimp has between twelve and sixteen. For years this was taken to mean it sees spectacular colours that humans can only dream of. A 2014 study then found it is actually worse than humans at telling similar colours apart, and probably uses all those receptors to recognise colours very quickly instead of very well.^[3] It has the best equipment on the reef and uses it like a shopping list.

See also

• Water – what it boils on the way past
• Bubble – its second punch
• Ocean – where it lives

References

1. Jab, J. (2005). Neither Mantis nor Shrimp. Reef Press.
2. Cavity, C. (2004). “The Second Punch”. Journal of Small Explosions 1: 2.
3. Spectrum, S. (2014). “All Those Receptors and Still Not Sure”. Vision Letters 16: 12.