The purpose of this study was to determine whether the western rattlesnake (Crotalus viridis) aims its predatory strike at the head/thorax region of mice primarily on the basis of cues related to the direction of prey movement. We hypothesized that when rattlesnakes strike at anesthetized, backward-moving mice, most strikes would be aimed at the forward-most-moving region, i.e., the posterior (abdomen/tail) region of prey. However, most mice were struck in the anterior (head/thorax) region, implying that the visual-infrared image of mice, rather than directional movement, guides the aim of predatory strikes.
Schmidt, Douglas F.; Hayes, William K.; and Hayes, Floyd E.
"Influence of prey movement on the aim of predatory strikes of the western rattlesnake (Crotalus viridis),"
Great Basin Naturalist: Vol. 53
, Article 14.
Available at: http://scholarsarchive.byu.edu/gbn/vol53/iss2/14