Piscivore

Northern water snake (Nerodia sipedon) eating a fish

A piscivore /ˈpɪsᵻvɔər/ is a carnivorous animal which eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the diet of early tetrapods (amphibians); insectivory came next, then in time, reptiles added herbivory.^[1]

Some animals, such as the sea lion and alligator, are not completely piscivorous, often preying on aquatic invertebrates or land animals in addition to fish, while others, such as the bulldog bat and gharial, are strictly dependent on fish for food. Humans can live on fish-based diets as can their carnivorous domesticated pets, such as dogs and cats. The name "piscivore" is derived from the Latin word for fish, piscis. Some creatures, including cnidarians, octopi, squid, spiders, sharks, cetaceans, grizzly bears, jaguars, wolves, snakes, turtles, and sea gulls, may have fish as significant if not dominant portions of their diets.

Examples of extant piscivores

• Aquatic genet
• Flat-headed cat
• Bulldog bat
• Sea lion
• Otter shrew
• European otter
• American mink
• Fishing cat
• Amazon river dolphin
• Giant otter
• Bottlenose dolphin
• Harbor seal
• Osprey
• Merganser
• Penguin
• Bald eagle
• Gharial
• Yellow-bellied sea snake
• African tigerfish
• Barracuda
• Lemon shark ^[2]
• Fishing spider

Extinct and prehistoric piscivores

Numerous extinct and prehistoric animals are either hypothesized to have been primarily piscivorous due to anatomy and or ecology, or have been confirmed to be piscivorous through fossil evidence.

Specimen of Diplomystus swallowing another fish

• Baryonyx (an opportunistic predator that had a crocodile-like skull, and scales of the lepidotid fish Scheenstia have been found in a skeleton where the stomach should be)^[3]
• Spinosaurus (close relative of Baryonyx, is hypothesized to have preyed on fish because of giant coelacanthids found in the same environment, and due to anatomical features, including a pressure-sensitive snout that could have detected movements of swimming prey)^[3][4]
• Laganosuchus (flattened head suggests that it passively waited for fish to swim near its mouth in order to engulf them)^[5]
• Pteranodon (remains of fish found in the beaks and stomach cavities of some specimens)
• Elasmosaurus (long neck, stereoscopicly positioned eyes, and long teeth are thought to be adaptations for stalking and trapping fish and other schooling animals)
• Thyrsocles (fossil specimen found with the stomach stuffed with the extinct herring Xyne grex)^[6]
• Xiphactinus (a 4-meter-long specimen was found with a perfectly preserved skeleton of its relative, Gillicus, in its stomach)
• Diplomystus (a small relative of the herring, numerous fossils of individuals that died while trying to swallow other fishes, including smaller individuals of the same species, are known)
• Ornithocheirus (hypothesized to be piscivorous due to anatomy of its jaws and dentition)
• Titanoboa (multiple crainial and tooth characteristics suggest it was primarily piscivorous)^[7]

References

1. Sahney, S., Benton, M. J. & Falcon-Lang, H. J. (2010). "Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica" (PDF). Geology 38 (12): 1079–1082. doi:10.1130/G31182.1.
2. Bright, Michael (2000). The private life of sharks : the truth behind the myth. Mechanicsburg, PA: Stackpole Books. ISBN 0-8117-2875-7.
3. Sereno, Paul C.; Beck, Allison L.; Dutheil, Didier B.; Gado, Boubacar; Larsson, Hans C. E.; Lyon, Gabrielle H.; Marcot, Jonathan D.; Rauhut, Oliver W. M.; Sadleir, Rudyard W.; Sidor, Christian A.; Varricchio, David D.; Wilson, Gregory P.; Wilson, Jeffrey A. (1998). "A long-snouted predatory dinosaur from africa and the evolution of spinosaurids". Science 282 (5392): 1298–302. Bibcode:1998Sci...282.1298S. doi:10.1126/science.282.5392.1298. PMID 9812890.
4. Dal Sasso, C.; Maganuco, S.; Cioffi, A. (26 May 2009). "A neurovascular cavity within the snout of the predatory dinosaur Spinosaurus". 1st International Congress on North African Vertebrate Palaeontology. Muséum national d'Histoire naturelle. Retrieved 22 September 2010.
5. Devlin, Hannah (November 20, 2009). "Meet Boar, Rat and Pancake: the ancient, giant crocodiles found in Sahara". Times Online.
6. David, Lore Rose. January 10, 1943. Miocene Fishes of Southern California The Society p 104-115
7. Head, J.J; Bloch, J. I; Moreno-Bernal, J. (2013). "Cranial Osteology, Body Size, Systematics and Ecology of the giant Paleocene snake Titanoboa cerrejonensis". Vertebrate Paleontology: 140–141.