The smell of hunger: Norway rats provision social partners based on odour cues of need

Karin Schneeberger, Gregory Röder & Michael Taborsky

Abstract When individuals exchange helpful acts reciprocally, increasing the benefit of the receiver can enhance its propensity to return a favour, as pay-offs are typically correlated in iterated interactions. Therefore, reciprocally cooperating animals should consider the relative benefit for the receiver when deciding to help a conspecific. Norway rats (Rattus norvegicus) exchange food reciprocally and thereby take into account both the cost of helping and the potential benefit to the receiver. By using a variant of the sequential iterated prisoner’s dilemma paradigm, we show that rats may determine the need of another individual by olfactory cues alone. In an experimental food-exchange task, test subjects were provided with odour cues from hungry or satiated conspecifics located in a different room. Our results show that wild-type Norway rats provide help to a stooge quicker when they receive odour cues from a hungry rather than from a satiated conspecific. Using chemical analysis by gas chromatography-mass spectrometry (GC-MS), we identify seven volatile organic compounds that differ in their abundance between hungry and satiated rats. Combined, this “smell of hunger” can apparently serve as a reliable cue of need in reciprocal cooperation, which supports the hypothesis of honest signalling.
Keywords Rats
Volatile organic compounds
Citation Schneeberger, K., Röder, G., & Taborsky, M. (2020). The smell of hunger: Norway rats provision social partners based on odour cues of need. Plos Biology, 18(3), 1-13.
Type Journal article (English)
Date of appearance 24-3-2020
Journal Plos Biology
Volume 18
Issue 3
Pages 1-13
URL https://doi.org/10.1371/journal.pbio.3000628