"Fiddler crabs wave their claws distinctively in a mating ritual to attract females (who must mate in the male burrows because the males cannot fit their large claws into the female burrows). This waving is also a prime defense against competing crabs, like soldier crabs." http://www.patreon.com/raocow https://talkhaus.raocow.com/viewtopic.php?f=3&t=17447