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The Language of Odors: Different Odor Dialects in Wild Otter Populations

Photo: Drew Avery, via Wikimedia Commons. Distributed under a CC BY 2.0 license.

Researchers from Cardiff University in Wales have shown for the first time that genetically distinct populations of wild mammals have different “odor dialects.” In a study published in Scientific Reports, they describe how populations of otters from across the UK possess sex- and biogeography-specific odors and speculate on how these odor dialects may affect individual behavior and conservation efforts.

Chemical communication is essential for most mammal species, underpinning territoriality, mate choice and reproduction, and parental care. In addition to providing identifying information regarding sex and age, odors may also signal genetic information. Such information could play a role in inbreeding avoidance and kin recognition.

Otters use secretions from a pair of anal glands in scent marking. The odor of these secretions is associated with an otter’s age, sex, reproductive status, and individual identity.

Photo: Cloudtail the Snow Leopard, via Flickr. Distributed under a CC BY-NC-ND 2.0 license.

Researchers with the Cardiff University Otter Project, led by Elizabeth Chadwick, investigated the relationship between genetic information and odor profiles in Eurasian otters (Lutra lutra) across England and Wales.

“To an extent, our results proved our hypothesis that there would be regional scent differences that mapped onto genetic differentiation,” says Chadwick.

Photo: Bernard Landgraf, via Wikimedia Commons. Distributed under a CC-BY-SA-3.0 license.

The evidence indicated that odor varies between genetically distinct subpopulations of otters. Subpopulations of otters with the most distinctive odor profiles were the most genetically diverse, but not the most genetically differentiated. And what’s more, geographic distance between otters did not explain regional odor differences, suggesting that geographical separation may drive a divergence in odor dialects.

Differences in odor dialects between subpopulations could impact reproduction and gene flow, keeping subpopulations reproductively isolated.

Chadwick says that with the recovery of the UK otter population, previously separated subpopulations are now contiguous.

“It is not clear whether the differences in scent signal might affect the nature of communication between individuals from different populations,” says Chadwick. “It might be that it hinders mixing, i.e., if they don’t “like” unfamiliar scents, or it may be that it enhances mixing, i.e., if they prefer to breed with different individuals to avoid inbreeding.

“Given the evidence that difference in scent do reflect genetic differentiation, it is something that ought to be given more attention, for instance in species recovery programs and captive releases.”



Kean, E. F., Bruford, M. W., Russo, I. M., Müller, C. T., and Chadwick, E. A. (2017). Odour dialects among wild mammals. Scientific Reports 7: 13593. doi: 10.1038/s41598-017-12706-8.

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