Forked tongue
A forked tongue is a tongue split into two distinct tines at the tip; this is a feature common to many species of reptiles. Reptiles smell using the tip of their tongue, and a forked tongue allows them to sense from which direction a smell is coming . Sensing from both sides of the head and following trails based on chemical cues is called tropotaxis.[1] It is unclear whether forked-tongued reptiles can actually follow trails or if this is just a hypothesis.[2][3][4]

Forked tongues have evolved in these squamate reptiles (lizards and snakes) for various purposes. The advantage to having a forked tongue is that more surface area is available for the chemicals to contact and the potential for tropotaxis.[5] The tongue is flicked out of the mouth regularly to sample the chemical environment. This form of chemical sampling allows these animals to sense non-volatile chemicals, which cannot be detected by simply using the olfactory system.[6][7][8] This increased ability to sense chemicals has allowed for heightened abilities to identify prey, recognize kin, choose mates, locate shelters, follow trails, and more.[8]
Forked tongues have evolved multiple times in squamates. It is unclear, based on the morphological and genetic evidence, where the exact points of change are from a notched tongue to a forked tongue, but it is believed that the change has happened two to four times.[1][9] A common behavioral characteristic that has evolved in those with forked tongues is that they tend to be wide foragers.[1][10]
Hummingbirds also have tongues that split at the tip.[11] Galagos (bushbabies) have a secondary tongue, or sublingua, used for grooming, hidden under their first.[12]
Usage as First Nations cultural term
The phrase "speaks with a forked tongue" means to deliberately say one thing and mean another or, to be hypocritical, or act in a duplicitous manner. In the longstanding tradition of many Native American tribes, "speaking with a forked tongue" has meant lying, and a person was no longer considered worthy of trust, once he had been shown to "speak with a forked tongue." This phrase was also adopted by Americans around the time of the Revolution, and may be found in abundant references from the early 19th century — often reporting on American officers who sought to convince the tribal leaders with whom they negotiated that they "spoke with a straight and not with a forked tongue" (as for example, President Andrew Jackson told the Creek Nation in 1829[13][14]). According to one 1859 account, the native proverb that the "white man spoke with a forked tongue" originated as a result of the French tactic of the 1690s, in their war with the Iroquois, of inviting their enemies to attend a Peace Conference, only to be slaughtered or captured.[15]
Literary usage
There are appearances of the phrase "forked tongue" in English literature, either in reference to actual snakes' tongues, or as a metaphor for untruthfulness, such as a sermon by Lancelot Andrewes, who died in 1626:
"And he hath the art of cleaving. He shewed it in the beginning, when he made the Serpent, linguam bisulcam, a forked tongue, to speake that, which was contrarie to his knowledge and meaning, They should not die; and as he did the Serpent's, so he can doe others."[16]
The phrase also appears in Milton's Paradise Lost:
- "According to his Doom: He would have spoke,
- But Hiss for Hiss return'd with forked Tongue
- To forked Tongue, for now were all transform'd..."[17]
See also
- Doublespeak
- Tongue splitting (a surgical procedure)
- Silver tongue (disambiguation)
- Ankyloglossia
- Dicroglossidae, family of frogs commonly called the fork-tongued frogs
References
- Schwenk, K. (March 1994). "Why snakes have forked tongues". Science. 263 (5153): 1573–1577. Bibcode:1994Sci...263.1573S. doi:10.1126/science.263.5153.1573. PMID 17744784. S2CID 28010522.
- Kubie, J.L.; Halpen, M. (1979). "Chemical senses involved in garter snake prey training". Journal of Comparative and Physiological Psychology. 93 (4): 648–447. doi:10.1037/h0077606.
- Waters, R.M. (1993). "Odorized air current trailing by garter snakes, Thamnophis sirtalis". Brain, Behavior and Evolution. 41 (3–5): 219–223. doi:10.1159/000113841. PMID 8477343.
- Parker, M.R.; Young, B.A.; Kardong, K.V. (2008). "The forked tongue and edge detection in snakes (Crotalus oreganus): an experimental test". Journal of Comparative Psychology. 122 (1): 35–40. doi:10.1037/0735-7036.122.1.35. PMID 18298279.
- Cooper, W.E. (April 1995). "Evolution and function of lingual shape in lizards, with emphasis on elongation, extensibility, and chemical sampling". Journal of Chemical Ecology. 21 (4): 477–505. doi:10.1007/BF02036744. PMID 24234178. S2CID 33016552.
- Baxi, K.N.; Dorries, K.M.; Eisthen, H.L. (January 2006). "Is the vomeronasal organ system really specialized for detecting pheromones?". Trends in Neurosciences. 29 (1): 1–7. doi:10.1016/j.tins.2005.10.002. PMID 16271402. S2CID 6487660.
- Shine, R.; Bonnet, X.; et al. (February 2004). "A novel foraging mode in snakes: browsing by the sea snake Emydocephalus annulatus (Serpentes, Hydrophiidae)". Functional Ecology. 18 (1): 16–24. doi:10.1046/j.0269-8463.2004.00803.x.
- Schwenk, K. (January 1995). "Of tongues and noses, chemoreception in lizards and snakes". Trends in Ecology & Evolution. 10 (1): 7–12. doi:10.1016/S0169-5347(00)88953-3. PMID 21236937.
- Townsend, T.M.; Larson, A.; et al. (October 2004). "Molecular phylogenetics of Squamata: the position of snakes, Amphisbaenians, and Dibamids, and the root of the squamate tree". Systematic Biology. 53 (5): 735–757. doi:10.1080/10635150490522340. PMID 15545252.
- Cooper, W.E. (1995). "Foraging mode, prey chemical discrimination, and phylogeny in lizards". Animal Behaviour. 50 (4): 973–985. doi:10.1016/0003-3472(95)80098-0. S2CID 53189324.
- Bill Hilton Jr (2007-06-12). "Hummingbird Internal Anatomy and Physiology". Operation RubyThroat: The Hummingbird Project. Hilton Pond Center for Piedmont Natural History. Retrieved 2008-02-13.
The tongue itself splits in the floor of the mouth
- Monkeyland. "Bushbaby - Galago moholi". Meet Our Primates. Monkeyland Primate Sanctuary. Archived from the original on 2007-10-22. Retrieved 2008-02-13.
equipped with a second, pointy tongue underneath their normal one
- Niles' Register, June 13, 1829
- Foster, Thomas Flournoy (1830). Speech on the Bill to Provide for the Removal of the Indians, West of the Mississippi: Delivered in the House of Representatives of the United States, May 17, 1830. D. Green. p. 11.
- Transactions of the New York State Agricultural Society, Vol 19, 1859, p. 230.
- Andrewes, Lancelot (1632-01-01). XCVI. Sermons. R. Badger.
- Milton, John; Rice, John (1766-01-01). Paradise Lost ... With notes of various authors, by John Rice. London.