Animal Behavior Interspecies Enemy Identification Depends on Facial Recognition

The formation of social groups is believed to confer a survival advantage to individual members of the group (reviewed by Marzluff, Walls, Cornell, Withey, and Craig, 2010). For humans, these advantages include the sharing of resources, information, skills, and childrearing tasks. Social groups are not limited to humans, but are also evident in species as diverse as ants, yellowfin tuna, and coyotes. However, our understanding of interspecies social interactions and the potential survival advantages that they confer are not understood to the same degree.

Domesticated animals, like dogs and cats, can readily distinguish friend or foe based on past interactions. Non-domesticated animals like the American crow (Corvus brachyrhynchos) seems to have the same capability. To better understand the parameters of 'enemy' recognition in crows, a group of researchers at the University of Washington in Seattle studied this phenomenon during a trap and release encounter. Essentially, Marzluff and colleagues (2010) proposed that crows remembered...

Being captured was interpreted by the crows as an adverse experience. The association between the mask and the adverse experience was tested, by researchers walking through the crow territories after they had been released. The main dependent variables measured were scolding, following, and mobbing.
Results

A Mask worn during trapping (enemy mask) elicited a significantly stronger scolding response than masks not worn during trapping (neutral masks) (Marzluff, Walls, Cornell, Withey, and Craig, 2010, 702). In addition, enemy masks had no effect on crows that had never been trapped. The variable 'no mask' had no effect, as long as the person was not present during trapping. In addition, a hat worn during trapping was capable of eliciting a significant modest scolding response, but not a red arm band.

One of the more surprising results was that the scolding response…