Table 1.
Body size and antipredator behaviors (mean ± 1 S.E.) exhibited during venom extractions of mainland (N = 20) and Santa Catalina Island (N = 10), California, USA, populations of the southern Pacific rattlesnake (Crotalus helleri).
| Measure | Mainland (N = 20) |
Catalina Island (N = 10) |
|---|---|---|
| Snout–vent length (cm) | 91 ± 4 | 72 ± 3 |
| Rattle before grasping (%) | 50.0 | 50.0 |
| Rattle during grasping (%) | 90.0 | 80.0 |
| Rattle during extraction (%) | 80.0 | 70.0 |
| Cloacal gland discharge (%) | 15.0 | 10.0 |
| Attempted to bite (%) | 15.0 | 70.0 |
| Latency to capture (s) | 7.7 ± 1.0 | 15.8 ± 2.2 |
| Venom expended (mg wet mass) a,b | 0.13 ± 0.02 | 0.27 ± 0.03 |
| Bilateral venom pulses (number) a,c | 2.0 ± 0.3 | 2.5 ± 0.2 |
| Venom per bite (mg) a,b | 0.07 ± 0.01 | 0.15 ± 0.02 |
a N = 19 (mainland) and 9 (Catalina); one snake in each population refused to deliver venom. b Estimated marginal means (corrected for body size) are at 85 cm for snout–vent length. c Venom pulses corresponded to a bilateral bite (i.e., sum of pulses observed from right and left fangs, divided by two); thus, a unilateral bite (pulse from a single fang) counted as half a bite.