Forked tongue

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File:Morelia spilota head.jpg
Forked tongue of a Carpet Python (Morelia spilota mcdowelli)

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.[9]

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.[10][11] A common behavioral characteristic that has evolved in those with forked tongues is that they tend to be wide foragers.[12][13]

Hummingbirds also have tongues that split at the tip.[14] Galagos (bushbabies) have a secondary tongue, or sublingua, used for grooming, hidden under their first.[15]

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[16]). 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.[17]

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, lingnam bisulcam, a forked tongue, to speake that, which was contrary to his knowledge and meaning, They should not die; and as hee did the Serpents, so hee can doe others."[18]

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..."[19]

See also

References

  1. Schwenk, K. 1994. Why snakes have forked tongues. Science 263:1573-1577.
  2. Kubie, J. L., and M. Halpern. 1979. Chemical senses involved in garter snake prey trailing. Journal of Comparative and Physiological Psychology 93:648-667.
  3. Waters, R. M. 1993, Odorizedair current trailing by garter snakes, Thamnophis sirtalis. Brain Behavior Evolution 41:219-223.
  4. Parker, M. R., B. A. Young, and K. V. Kardong. 2008. The forked tongue and edge detection in snakes (Crotalus oreganus): an experimental test. Journal of Comparative Psychology 122:35-40.
  5. Cooper, W. E. 1995a. Evolution and function of lingual shape in lizards, with emphasis on elongation, extensibility, and chemical sampling. Journal of Chemical Ecology 21:477-505.
  6. Baxi, K. N., K. M. Dorries, and H. L. Eisthen. 2006. Is the vomeronasal organ system really specialized for detecting pheromones? Trends in Neurosciences 29:1-7.
  7. Shine, R., X. Bonnet, M. J. Elphick, and E. G. Barrott. 2004. A novel foraging mode in snakes: browsing by the sea snake Emydocephalus annulatus (Serpentes, Hydrophiidae). Functional Ecology 18:16-24.
  8. Schwenk, K. 1995. Of tongues and noses, chemoreception in lizards and snakes. Trends in Ecology & Evolution 10:7-12.
  9. Schwenk, K. 1995. Of tongues and noses, chemoreception in lizards and snakes. Trends in Ecology & Evolution 10:7-12.
  10. Schwenk, K. 1994. Why snakes have forked tongues. Science 263:1573-1577.
  11. Townsend, T. M., A. Larson, E. Louis, and J. R. Macey. 2004. Molecular phylogenetics of Squamata: the position of snakes, Amphisbaenians, and Dibamids, and the root of the Squamate tree. Systematic Biology 53:735-757.
  12. Schwenk, K. 1994. Why snakes have forked tongues. Science 263:1573-1577
  13. Cooper, W. E. 1995b. Foraging mode, prey chemical discrimination, and phylogeny in lizards. Animal Behaviour 50:1709-1709.
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  16. Niles' Register, June 13, 1829
  17. Transactions of the New York State Agricultural Society, Vol 19, 1859, p. 230.
  18. https://books.google.com/books?id=iONBAQAAMAAJ&pg=PA604&dq=%22forked+tongue%22&hl=en&sa=X&ei=KiRTVLXgMImrjALk04CYAQ#v=onepage&q=%22forked%20tongue%22&f=false
  19. https://books.google.com/books?id=68BYAAAAcAAJ&pg=PA393&dq=%22forked+tongue%22&hl=en&sa=X&ei=wTpTVNaXI5HViALjoIGwCA&ved=0CDQQ6AEwBA#v=onepage&q=%22forked%20tongue%22&f=false