Deep sea anglerfish are known for their frightening appearance and use of bioluminescent lures in order to catch their prey. Contrary to popular belief, only female anglerfish have a bioluminescent lure, which is located just above the jaw. Female anglerfish tend to be markedly larger than male anglerfish, with male anglerfish adopting a parasitic relationship with the female during mating. Once the male has fused with the female, he remains attached to her for the duration of her lifespan and is nourished by her bloodstream. Anglerfish can be pelagic or benthic, which refers to the depth of the ocean at which they dwell. Pelagic anglerfish are laterally compressed whereas benthic anglerfish are dorsoventrally compressed. Anglerfish are thought to have diversified during the early to mid Cretaceous period, between 130 and 100 million years ago.