Olfactory discrimination between litter mates by mothers and alien adult cats: lump or split?
Mother cats can discriminate between their own and alien kittens using kittens’ body odour. Here we ask whether they can also distinguish between body odours of kittens from the same litter. We conducted three experiments using the habituation–dishabituation technique with the odour of 1- and 7-week-old kittens of both sexes. In Experiment 1, we found no evidence that mothers discriminated among their own kittens of either age when presented three times with the odour of one individual (habituation trials) and then with the odour of a different individual (dishabituation or discrimination trial), even when the donor kittens were of different sex. In Experiment 2, alien adults of both sexes distinguished between 7 but not between 1-week-old litter mates. In Experiment 3, mothers distinguished between unknown litter mates in a similar and age-dependent manner to the animals of Experiment 2. We conclude that litter mates possess individual odour signatures that can be discriminated by adult cats, that these cues take some time to develop, but are not discriminated by their own mother, at least not during the pre-weaning period. Mothers possibly perceive and respond to a learned “nest”/litter odour shared by all litter mates or categorize the individual odours of their kittens as belonging to an “own kitten” category. That mothers did not discriminate between the odours of their own kittens but did so between individual kittens of alien litters suggests that different levels of processing olfactory information exist in mothers’ ability to cognitively partition and differentially respond to such odours.
KeywordsDomestic cat Felis silvestris catus Habituation–dishabituation technique Individual recognition Odour discrimination Olfaction
Financial support was provided by a research grant from the Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (DGAPA-IN212416), to O. B. by the Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, and a doctoral fellowship to E. J. from the Consejo Nacional de Ciencia y Tecnología, México. We thank Royal Canin® for generous support in maintaining our cat colony, Andrea Urrutia for help with behavioural testing, Carolina Rojas for excellent technical assistance, and 28 private cat owners for allowing us access to their homes and pets. We also thank the reviewers for their helpful comments.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed were in accordance with the ethical standards of the institution or practice at which the studies were conducted. Throughout the study, animals were kept and treated according to the Guide for the Production, Care and Use of Laboratory Animals Mexico (Norma Oficial Mexicana NOM-062-200-1999), and with approval by the Institutional Committee for the Care and Use of Experimental Animals (SICUAE, permission number DC-2017/1–4) of the Faculty of Veterinary Medicine and Animal Science of the UNAM. This article does not contain any studies with human participants performed by any of the authors.
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