Have you ever seen a tadpole shrimp? Members of the genus Triops, these small crustaceans can be found in a wide range including North America, South America and Asia. Measuring up to 4 cm (1.5 in) long, they inhabit the bottom of murky freshwater pools. These bugs have three eyes, including two compound eyes and a primitive light-sensing organ, as well as long antennae that they use to find food in their muddy habitats. Their life expectancy is only about 40 days.