Parasitic males and fish tails

I caught a glimpse of one of those countdown shows last week about weird animals and I thought I’ll share with you their number one wackiest animal ever (!). And it is the deep sea anglerfish. This animal has a face which would easily scare a child...

(Much of this article comes from http://waynesword.palomar.edu/ww0701.htm#Angler)

The deep sea anglerfish has huge jaws which are well adapted to snatch any prey unfortunate to come into range. It lives in total darkness and because of the sparseness of life in these waters some species of the female deep sea anglerfish carries a stalked, luminous bait above her. The bioluminescent of the stalk is used to attract curious fish towards that mouth.

But it is possible that the weirdest aspect of these creatures is their mating habits. Males of the species are discovered by deep sea anglers who discovered that small "growths" on the female are actually males. In fact, when a tiny male meets a female he bits into her flesh and literally fuses with her body. They share blood supplies so the male obtains nutrients and oxygen from the female. Without any need for most of his organ systems, such as eyes and digestive organs, the male's body degenerates into essentially a pair of sperm-producing testicles. Thus the female essentially becomes a hermaphrodite with up to six or more of these tiny male parasites attached to various parts of her body. Although functionally bisexual, the eggs and sperm come from genetically distinct parents, thus providing vital genetic variability through meiosis and genetic recombination. As a functional hermaphrodite she can have sex any time or place, without worrying about meeting a male in the dark abyss of the ocean. Clinging to her body like minute, blood-sucking parasites, the males have little interaction with the female, except to fertilize her eggs with sperm.
by Emily Wong