title: Target tracking during venom 'spitting' by cobras.
abstract: Spitting cobras, which defend themselves by streaming venom towards the face and/or eyes of a predator, must be highly accurate because the venom they spit is only an effective deterrent if it lands on the predator's cornea. Several factors make this level of accuracy difficult to achieve; the target is moving, is frequently >1 m away from the snake and the venom stream is released in approximately 50 ms. In the present study we show that spitting cobras can accurately track the movements of a potentially threatening vertebrate, and by anticipating its subsequent (short-term) movements direct their venom to maximize the likelihood of striking the target's eye. Unlike other animals that project material, in spitting cobras the discharge orifice (the fang) is relatively fixed so directing the venom stream requires rapid movements of the entire head. The cobra's ability to track and anticipate the target's movement, and to perform rapid cephalic oscillations that coordinate with the target's movements suggest a level of neural processing that has not been attributed to snakes, or other reptiles, previously.
authors.affiliation: Institute of Zoology, University of Bonn, Bonn 53115, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Westhoff
authors.forename: Melissa
authors.initials: M
authors.lastname: Boetig
authors.forename: Horst
authors.initials: H
authors.lastname: Bleckmann
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Young
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004546:Elapid Venoms / Q000378:metabolism*; D017815:Elapidae / Q000502:physiology*; D009068:Movement; D011235:Predatory Behavior
chemical_list: D004546:Elapid Venoms
references.citation: Oecologia. 1985 Jan;65(2):284-288
references.pmid: 28310679
references.citation: J Exp Biol. 2004 Sep;207(Pt 20):3483-94
references.pmid: 15339944
references.citation: Experientia. 1991 Feb 15;47(2):205-9
references.pmid: 2001726
references.citation: J Exp Biol. 2002 Nov;205(Pt 21):3321-6
references.pmid: 12324541
references.citation: Physiol Biochem Zool. 2009 Jan-Feb;82(1):63-79
references.pmid: 19025501
references.citation: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2009 Aug;195(8):753-7
references.pmid: 19462171
references.citation: J Exp Biol. 1998 Mar;201 (Pt 6):837-50
references.pmid: 9464964
references.citation: Toxicon. 1999 Sep;37(9):1271-9
references.pmid: 10400288
references.citation: Behav Processes. 2001 Aug 15;55(2):93-105
references.pmid: 11470501
references.citation: Physiol Biochem Zool. 2009 Jan-Feb;82(1):80-9
references.pmid: 19046067
references.citation: J Exp Biol. 2000 Nov;203(Pt 21):3255-63
references.pmid: 11023845
references.citation: Am J Trop Med Hyg. 1976 May;25(3):525-9
references.pmid: 1084700
references.citation: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2008 Oct;194(10):871-8
references.pmid: 18704442
references.citation: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2005 Oct;191(10):873-81
references.pmid: 16007458
references.citation: Mol Phylogenet Evol. 2007 Nov;45(2):437-53
references.pmid: 17870616
references.citation: J Opt Soc Am A. 1987 Mar;4(3):530-9
references.pmid: 3572580
references.citation: Vision Res. 1988;28(12):1323-35
references.pmid: 3256150
references.citation: Curr Biol. 2006 Feb 21;16(4):378-83
references.pmid: 16488871