The buccal buckle: the functional morphology of venom spitting in cobras

Functional Bases of the Spatial Dispersal of Venom during Cobra “Spitting”

“…The results of this study support the functional model for venom spitting put forth by Young et al (2004), but they also reveal that the functional specializations for venom spitting in cobras are more complex than detailed in that earlier publication. More specifically, spitting cobras functionally couple the seemingly autonomous cervical axial muscles and the venomdelivery system.…”

“…Freyvogel and Honegger (1965) generated artificial spits by applying electrical stimulation to the lateral jaw muscles of anesthetized spitting cobras. Young et al (2004) combined this finding with the repeated observation (e.g., Pitman 1974;Broadley 1983) that the supralabial scalation of spitting cobras displaces during spitting (suggesting an underlying displacement of the maxilla) to produce a more complete model for the functional basis of venom spitting. The model put forth by Young et al (2004) proposed that venom spitting in cobras utilized the same two key elements found in venom expulsion in viperid snakes: skeletal muscle contraction to pressurize the venom gland and displacement of the fang sheath (Young et al 2002(Young et al , 2003Young and Kardong 2007).…”

“…Rapid oscillations of the cobra's head during venom spitting have been previously described (e.g., Young et al 2004;Westhoff et al 2005). These cephalic oscillations, like the spatial-dispersal patterns of venom, typically exhibit complex geometric patterns (Fig.…”

Functional Bases of the Spatial Dispersal of Venom during Cobra “Spitting”

“…The results of this study support the functional model for venom spitting put forth by Young et al (2004), but they also reveal that the functional specializations for venom spitting in cobras are more complex than detailed in that earlier publication. More specifically, spitting cobras functionally couple the seemingly autonomous cervical axial muscles and the venomdelivery system.…”

“…Freyvogel and Honegger (1965) generated artificial spits by applying electrical stimulation to the lateral jaw muscles of anesthetized spitting cobras. Young et al (2004) combined this finding with the repeated observation (e.g., Pitman 1974;Broadley 1983) that the supralabial scalation of spitting cobras displaces during spitting (suggesting an underlying displacement of the maxilla) to produce a more complete model for the functional basis of venom spitting. The model put forth by Young et al (2004) proposed that venom spitting in cobras utilized the same two key elements found in venom expulsion in viperid snakes: skeletal muscle contraction to pressurize the venom gland and displacement of the fang sheath (Young et al 2002(Young et al , 2003Young and Kardong 2007).…”

“…Rapid oscillations of the cobra's head during venom spitting have been previously described (e.g., Young et al 2004;Westhoff et al 2005). These cephalic oscillations, like the spatial-dispersal patterns of venom, typically exhibit complex geometric patterns (Fig.…”

Spitting versus Biting: Differential Venom Gland Contraction Regulates Venom Expenditure in the Black-Necked Spitting Cobra, Naja nigricollis nigricollis

“…The most important analysis was whether venom pulse duration during biting, measured here, exceeded that reported in a previous study for spitting (mean 5 0.066 sec from one specimen of unspecified size between 45 and 130 cm SVL, Young et al, 2004; 0.048-0.060 sec from another specimen between 150 and 180 cm SVL, Westhoff et al, 2005). Because the bite analyses above suggested independence between pulses from right and left fangs and among the three successive pulses, we pooled all of the pulses (including both independent and related data, mildly failing a Kolmogorov-Smirnov test for normality: P 5 0.049) for comparison to the single value for spitting.…”

“…The results were unequivocal. The duration of venom pulses ejected from a fang during biting (mean 5 0.35 sec; median 5 0.25 sec) exceeded by nearly fourfold (P , 0.001) that reported for spitting (mean 5 0.066 sec; Young et al, 2004;cf. Westhoff et al, 2005).…”

Functional Bases of the Spatial Dispersal of Venom during Cobra “Spitting”

“…The results of this study support the functional model for venom spitting put forth by Young et al (2004), but they also reveal that the functional specializations for venom spitting in cobras are more complex than detailed in that earlier publication. More specifically, spitting cobras functionally couple the seemingly autonomous cervical axial muscles and the venomdelivery system.…”

“…Freyvogel and Honegger (1965) generated artificial spits by applying electrical stimulation to the lateral jaw muscles of anesthetized spitting cobras. Young et al (2004) combined this finding with the repeated observation (e.g., Pitman 1974;Broadley 1983) that the supralabial scalation of spitting cobras displaces during spitting (suggesting an underlying displacement of the maxilla) to produce a more complete model for the functional basis of venom spitting. The model put forth by Young et al (2004) proposed that venom spitting in cobras utilized the same two key elements found in venom expulsion in viperid snakes: skeletal muscle contraction to pressurize the venom gland and displacement of the fang sheath (Young et al 2002(Young et al , 2003Young and Kardong 2007).…”

“…Rapid oscillations of the cobra's head during venom spitting have been previously described (e.g., Young et al 2004;Westhoff et al 2005). These cephalic oscillations, like the spatial-dispersal patterns of venom, typically exhibit complex geometric patterns (Fig.…”

Spitting versus Biting: Differential Venom Gland Contraction Regulates Venom Expenditure in the Black-Necked Spitting Cobra, Naja nigricollis nigricollis

“…The most important analysis was whether venom pulse duration during biting, measured here, exceeded that reported in a previous study for spitting (mean 5 0.066 sec from one specimen of unspecified size between 45 and 130 cm SVL, Young et al, 2004; 0.048-0.060 sec from another specimen between 150 and 180 cm SVL, Westhoff et al, 2005). Because the bite analyses above suggested independence between pulses from right and left fangs and among the three successive pulses, we pooled all of the pulses (including both independent and related data, mildly failing a Kolmogorov-Smirnov test for normality: P 5 0.049) for comparison to the single value for spitting.…”

“…The results were unequivocal. The duration of venom pulses ejected from a fang during biting (mean 5 0.35 sec; median 5 0.25 sec) exceeded by nearly fourfold (P , 0.001) that reported for spitting (mean 5 0.066 sec; Young et al, 2004;cf. Westhoff et al, 2005).…”

Functional Bases of the Spatial Dispersal of Venom during Cobra “Spitting”

“…The results of this study support the functional model for venom spitting put forth by Young et al (2004), but they also reveal that the functional specializations for venom spitting in cobras are more complex than detailed in that earlier publication. More specifically, spitting cobras functionally couple the seemingly autonomous cervical axial muscles and the venomdelivery system.…”

“…Freyvogel and Honegger (1965) generated artificial spits by applying electrical stimulation to the lateral jaw muscles of anesthetized spitting cobras. Young et al (2004) combined this finding with the repeated observation (e.g., Pitman 1974;Broadley 1983) that the supralabial scalation of spitting cobras displaces during spitting (suggesting an underlying displacement of the maxilla) to produce a more complete model for the functional basis of venom spitting. The model put forth by Young et al (2004) proposed that venom spitting in cobras utilized the same two key elements found in venom expulsion in viperid snakes: skeletal muscle contraction to pressurize the venom gland and displacement of the fang sheath (Young et al 2002(Young et al , 2003Young and Kardong 2007).…”

“…Rapid oscillations of the cobra's head during venom spitting have been previously described (e.g., Young et al 2004;Westhoff et al 2005). These cephalic oscillations, like the spatial-dispersal patterns of venom, typically exhibit complex geometric patterns (Fig.…”

Spitting versus Biting: Differential Venom Gland Contraction Regulates Venom Expenditure in the Black-Necked Spitting Cobra, Naja nigricollis nigricollis

“…The most important analysis was whether venom pulse duration during biting, measured here, exceeded that reported in a previous study for spitting (mean 5 0.066 sec from one specimen of unspecified size between 45 and 130 cm SVL, Young et al, 2004; 0.048-0.060 sec from another specimen between 150 and 180 cm SVL, Westhoff et al, 2005). Because the bite analyses above suggested independence between pulses from right and left fangs and among the three successive pulses, we pooled all of the pulses (including both independent and related data, mildly failing a Kolmogorov-Smirnov test for normality: P 5 0.049) for comparison to the single value for spitting.…”

“…The results were unequivocal. The duration of venom pulses ejected from a fang during biting (mean 5 0.35 sec; median 5 0.25 sec) exceeded by nearly fourfold (P , 0.001) that reported for spitting (mean 5 0.066 sec; Young et al, 2004;cf. Westhoff et al, 2005).…”