An Analysis of Snake‐Scent Application Behaviour in Siberian Chipmunks (Eutamias sibiricus asiaticus)

Abstract

Some rodents assault live snakes by mobbing. Another snake‐directed behaviour is shown by Siberian chipmunks, Eutamias sibiricus asiaticus, when encountering a dead snake. They approach the carcass cautiously, gnaw the snake skin, and chew and apply the gnawed bits to their body fur. We have termed this behaviour “Snake‐Scent Application” (SSA). SSA behaviour is also elicited by snake urine and feces. Chemicals in snake skin and rectal and cloacal sacs release SSA. Snake urine applied to dead mice tends to suppress ingestion by snakes.

Fossils and phylogeny uncover the evolutionary history of a unique antipredator behaviour

“…Six ground squirrel ( Spermophilus ) species and one antelope squirrel ( Ammospermophilus ) species were tested at two locations each, and two chipmunk species ( Neotamias ) were tested at single locations (hereafter distinct locations will be referred to as populations; Table S1). We also included a chipmunk and ground squirrel species tested with snake scent by other researchers ( Eutamias sibiricus , Kobayashi & Watanabe, 1986; Spermophilus spilosoma , P. Arrowood, unpublished data).…”

“…It is not known whether this behaviour evolved specifically because of the unique predator–prey relationship between rattlesnakes and these two ground squirrel species or whether it evolved in a more distant common ancestor in some other context. For example, there is evidence that predator scent application behaviour is expressed in other rodents: Siberian chipmunks ( Eutamias sibiricus ) and Southern grasshopper mice ( Onychomys torridus ) seem to apply snake scent in a manner very similar to ground squirrels (Kobayashi & Watanabe, 1986; M. Rowe 2000, unpublished data; respectively) and the Chinese rice‐field rat ( Rattus rattoides ) has been reported to apply the anal gland secretions of predator weasels ( Mustela sibirica ; Xu et al. , 1995; see Clucas et al.…”

Antipredator behavior.

“…Diverse taxa of nonpoisonous or nonvenomous animals, including insects, fish, and snakes, mimic poisonous or venomous animals and deceive predators to deter predation (Ruxton et al, 2004). Some squirrels (Eutamias sibiricus asiaticus, Spermophilus beecheyi, and S. variegatus) rub snake skins and add the scents to their body surface so as to evade predation (Clucas, Rowe, Owings, & Arrowood, 2008;Kobayashi & Watanabe, 1986). When these animals depend on resources of other species, they face a unique decision about defensive tactics.…”

Donning your enemy's cloak: ground squirrels exploit rattlesnake scent to reduce predation risk

“…Rodents, for example, self-apply the scent of their predators by chewing on the scent source and licking their bodies. Chipmunks, ground squirrels, and grasshopper mice apply snake scent in this way (Kobayashi & Watanabe 1986;Clucas et al 2008;M. Rowe 2000, unpublished data), and rats and ground squirrels apply weasel anal gland secretions ( Xu et al 1995;B.…”

“…Clucas 2006, unpublished data). These commandeered odours may reduce predation (Brodie 1977;Kobayashi & Watanabe 1986;Xu et al 1995;Clucas et al 2008), but the effects of the applied scent on predators have not yet been tested systematically. Some ground squirrels (Spermophilus spp.)…”