Most complex eyes of any animal
Stomatopod, Mantis shrimp
16 total number
Not Applicable ()

Native to tropical and subtropical waters worldwide, certain species of stomatopod crustacean, aka mantis shrimp – such as those in the superfamilies Gonodactyloidea, Lysiosquilloidea and Hemisquilloidea – are considered to have the most complex eyes in the animal kingdom. Their compound eyes, made up of thousands of repeating units called ommatidia, can contain as many as 12–16 different photoreceptors, compared to four in the human eye. For the upper limit of this range, 12 receptors are dedicated to colour analysis (providing a wavelength range of 300–720 nanometres from deep ultraviolet to far red) and the remaining four are used to detect polarised light.

By comparison, the eyes of most mammals contain two types of colour photoreceptor, humans have three (red, green and blue; this increases to four photoreceptors in total if including non-colour-processing rod cells), while most birds and reptiles have four.

A 2014 study by the University of Queensland in Australia indicated that a mantis shrimp's large number of photoreceptors has evolved not necessarily to detect a greater range of colour, but in order to perceive colour more quickly and efficiently – a biological advantage that enables these crustaceans to rapidly identify both prey and predators against the multi-coloured reef habitats where most stomatopods live.