Episodic-like memory in crossbred Yucatan minipigs (Sus scrofa)

Episodic-like memory, involving simultaneous recall of what, where and when aspects of a past event, has been demonstrated in some non-human species and is hippocampal-dependent. Our study explored episodic-like memory in pigs, a previously un-studied species that has shown evidence of highly developed mental abilities in other cognitive tests. We used a definition of episodic-like memory that equates the recall of time ("when") with the recall of context ("which"). Pigs performed a novel object recognition test and identified the less familiar of two object/location/context configurations. Since configurations only differed in familiarity if all aspects were remembered simultaneously, we concluded that pigs did recall what/where/which. This finding provides the first evidence of episodic-like memory in pigs. We discuss possible implications for pig welfare and identify future avenues of research. (C) 2009 Elsevier B.V. All rights reserved.