The male anglerfish undertakes an extraordinary mating process in the deep ocean. The tiny male must locate a female many times his size and, once found, bites her skin. Their bodies then merge as their circulatory systems join, making him a permanent part of her. He receives nutrients from her blood and supplies sperm when needed, ensuring the species continues in an environment where finding a mate is nearly impossible. His unique immune system, lacking certain key genes, prevents rejection du