Megamouth shark to be the sole extant species in the distinct family Megachasmidae, though suggestion has been made that it may belong in the family Cetorhinidae, of which the basking shark is currently the sole extant member. Researchers have predicted the feeding patterns of megamouth sharks in relation to the other two planktivorous sharks; the three plankivourous sharks have ram feeding in common, as it evolved from ram feeding swimming-type ancestors that developed their filtering mechanism to capture small prey like plankton. In addition to the living "M. pelagios", however, two extinct megamouth species – the Priabonian "M. alisonae" and the Oligocene–Miocene
Fear of fish by what is now called graduated exposure therapy: In contrast, radical exposure therapy was used successfully to cure a man with a "life affecting" fish phobia on the 2007 documentary series, "The Panic Room". Historically, the Navajo people were described as being ichthyophobic, due to their aversion to fish. However, this was later recognised as a cultural or mythic aversion to aquatic animals, and not a psychological condition. The "Journal of the American Medical Association" have published a research paper addressing the fears of eating fish because contaminants, such as mercury may be accumulated in fish. In his autobiography, Italian