Cues used during poststrike trailing in rattlesnakes

SMITH, T.L.*; KARDONG, K.V.: Cues used during poststrike trailing in rattlesnakes

Research on snake predatory behavior has involved identifying the specific cues eliciting foraging and attack behaviors. Prey integument and feces have been shown to produce behaviors correlated with increased predatory behavior. In addition, recent studies have shown that blood, itself, provides similar cues in some groups of snakes. It has been proposed that blood acquired during a predatory strike in rattlesnakes might elicit elevated levels of tongue-flicking. Rattlesnakes typically release rodents immediately poststrike, and exhibit a high rate of tongue flicking along with increased movement. Collectively these behaviors have been defined as strike-induced chemosensory searching (SICS). The strike releases SICS, and it releases specific poststrike trailing of the envenomated rodent. The exact cue (or cues) used during poststrike trailing is unknown, but integumentary cues (mouse odor) are likely used to locate and follow the trail of the envenomated rodent. Because blood has been shown to elicit SICS, we asked if blood might also serve as a chemosensory cue guiding poststrike trailing as well. In other words, can rattlesnakes (Crotalus viridis oreganus) use blood, alone, as a prey odor trail during poststrike trailing? Fifteen snakes were run in a series of Y-maze choice trials, presenting them with blood from the mouse they just envenomated versus a control trail. We found that although the group of snakes showed an elevated rate of tongue-flicking, poststrike, they failed to follow a blood trail alone. Therefore, although blood seems to elicit SICS, it is not a chemosensory cue used directly in poststrike trailing.

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