Does rattling deter? The case of domestic dogs

Abstract

Although the rattling of rattlesnakes (Crotalus and Sistrurus) is widely accepted as being aposematic, the hypothesis that rattling deters approach from the snake's potentially dangerous adversaries has not been well tested. In a controlled study using rattling recorded from captive rattlesnakes (C. oreganus helleri) and a variety of comparison sounds or no‐sound controls, domestic dogs (Canis familiaris) showed no hesitation to approach camouflaged speakers projecting the recorded rattles. The dogs were equally likely to approach speakers projecting rattling as they were to approach speakers playing control sounds, or speakers that were silent. Furthermore, the dogs spent no less time in front of the speakers projecting the rattles than they did in front of speakers projecting control sounds or no sound. The dogs' reactions may not be representative of other species with whom rattlesnakes come into contact, but the data suggest a need for some circumspection about the role of rattling in the rattlesnake's defensive repertoire. Our results also suggest that dogs may be vulnerable to envenomation because they fail to react to the sound of rattling with avoidance.

Sounds and associated morphology of Hypostomus species from South‐East Brazil

“…However, even with an aposematic function, it is possible to find interspecific differences in the highly diverse taxa of Siluriformes since Heyd and Pfeiffer (2000) and Kaatz (1999) have found some species differences related to number of ridges and their widths. Acoustic aposematic signals are found in different clades (Heyd & Pfeiffer, 2000) like insects (Ratcliffe et al., 2008), frogs (Santos et al., 2014), and snakes (Caine et al., 2020). Perhaps one of the best‐known examples of aposematic sounds can be found in the rattlesnakes of the Crotalus and Sistrurus genera (Caine et al., 2020).…”

“…Acoustic aposematic signals are found in different clades (Heyd & Pfeiffer, 2000) like insects (Ratcliffe et al., 2008), frogs (Santos et al., 2014), and snakes (Caine et al., 2020). Perhaps one of the best‐known examples of aposematic sounds can be found in the rattlesnakes of the Crotalus and Sistrurus genera (Caine et al., 2020). However, the evidence of an aposematic sound function in rattlesnakes is in debate (Caine et al., 2020).…”

“…Perhaps one of the best‐known examples of aposematic sounds can be found in the rattlesnakes of the Crotalus and Sistrurus genera (Caine et al., 2020). However, the evidence of an aposematic sound function in rattlesnakes is in debate (Caine et al., 2020). Some authors have proposed that the rattling is not used to warn but to direct threatening attention away from the snake's head (Williams, 1966), and the rattling is observed only in defensive contexts (Greene, 1988) making unlikely the ‘caudal luring’ hypothesis for rattlesnakes (Schuett et al., 1984; Sisk & Jackson, 1997).…”

“…Some authors have proposed that the rattling is not used to warn but to direct threatening attention away from the snake's head (Williams, 1966), and the rattling is observed only in defensive contexts (Greene, 1988) making unlikely the 'caudal luring' hypothesis for rattlesnakes (Schuett et al, 1984;Sisk & Jackson, 1997). In addition, some species of birds (Owings et al, 2002) and nonvenomous snakes (Kardong, 1980;Sweet, 1985) can mimic rattling, reinforcing the hypothesis of a protective function (Caine et al, 2020). Hypostomus sounds could also have an alarm or distress function without an aposematic function.…”

Frequency modulation of rattlesnake acoustic display affects acoustic distance perception in humans

“…Therefore, we hypothesize that similar changes in rattling behavior might lead to similar changes in behavior in other animals, as in our observations in humans. While rattling does not effectively deter all animals 27 and can even be exploited by other (highly adapted) species to assess the threat of a snake, 11 there is a consensus that it is being employed as an effective deterrent. 28 Interestingly, burrowing owls employ a similar sound, also with a deterrent effect on other animals.…”