Farzana Anjum, Robert Naumann, Claudia Roth-Alpermann, Michael Brecht

While visuomotor behaviors and visual object recognition have been studied in detail, we know relatively little about tactile object representations. We investigate a new model system for the tactile guidance of behavior, namely prey (cricket) capture by one of the smallest mammals, the Etruscan shrew, Suncus etruscus. Due to their high metabolic rate and nocturnal lifestyle, Etruscan shrews are forced to detect, overwhelm and kill prey in large numbers in darkness. Crickets are exquisitely mechanosensitive, fast moving prey, almost as big as the shrew itself. Shrews succeed in hunting by lateralized, precise and fast attacks. Removal experiments demonstrate that both macro- and microvibrissae are required for prey capture, with the macrovibrissae being involved in attack targeting. Experiments with artificial prey replica show that tactile shape cues are both necessary and sufficient for evoking attacks. Prey representations are motion- and size-invariant. Shrews distinguish and memorize prey features. Corrective maneuvers and cricket shape manipulation experiments indicate that shrew behavior is guided by Gestalt-like prey descriptions. Thus, tactile object recognition in Etruscan shrews shares characteristics of human visual object recognition, but it proceeds faster and occurs in a 20000-fold smaller brain.