You probably know a couple who seem inseparable, but even the clingiest human relationships have nothing on anglerfish. When males find their ‘true love’ they bite on and never let go, eventually becoming just a small extension of her much-larger body.
It’s been said that maybe only one percent of male anglerfish actually find a mate (and even those that do often have to share). Because of this, it shouldn’t be surprising that once they do, they decide to form a permanent connection.
They bite onto the female, which can be up to sixty times longer and half a million times heavier than he is. The two fish then slowly fuse together as the male’s organs disappear; eventually he completely relies on the female to survive.
This arrangement wouldn’t work for most other animals – our immune systems are designed to fight anything that doesn’t belong in our bodies. Anglerfish DNA is missing these instructions, allowing their bizarre mating practice to continue.
Lachlan Writes Science 