Observations in iNaturalist remain insufficient to draw the border between the two subspecies of the vicuna

@michalsloviak @michaelweymann @tonyrebelo @jwidness @diegoalmendras @geichhorn

Please see:

Please also see my own recent Post about the vicuna (https://www.inaturalist.org/journal/milewski/74636-adaptive-colouration-in-the-vicuna-camelidae-vicugna-vicugna#).

The two subspecies of the vicuna (Vicugna vicugna) differ as follows.

The northern subspecies, Vicugna vicugna mensalis, possesses a conspicuous tract of pale pelage on and around the chest, with the whitish hairs on the chest itself being noticeably longer than those anywhere else on the figure. Please see the third photo in https://www.magazinehorse.com/en/vicuna/.

The southern subspecies, Vicugna vicugna vicugna, instead possesses a broad tract of fairly pale (but not particularly conspicuous) pelage on the posterior flanks, extending up to the level of the ileum (hip), as shown in https://www.flickr.com/photos/wdbowman/41823663541.

One of the puzzling aspects of the vicuna is that there is no obvious geographical barrier between the two subspecies. Instead, the distinction seems to be mainly latitudinal, within the endorheic region of the altiplano (https://en.wikipedia.org/wiki/Altiplano).

There are now more than a thousand observations of the vicuna in iNaturalist, offering the prospect of locating the subspecies-border precisely.

Today, I scrutinised the observations, but failed to locate this border satisfactorily.

This failure was because

  • many of the observations in the region concerned are too unclear, owing to photographic problems of distance and illumination, and
  • those photos that do clearly show the colouration present a confusing geographical pattern, at a small scale.

Just north of a north-south gap in the observations: https://www.inaturalist.org/observations/21493503 is identifiable as subspecies mensalis.

The first observation south of this gap is: https://www.inaturalist.org/observations/137351143, which is identifiable as subspecies vicugna.

This suggests that the subspecies-border lies at the latitude of Salinas de Garci Mendoza (https://en.wikipedia.org/wiki/Salinas_de_Garci_Mendoza), viz. 19 degrees 38 minutes South.


An observation in this general area showing subspecies vicugna is https://www.inaturalist.org/observations/103617990. This is at 20 degrees 31 minutes South.

So, the above observations collectively indicate that the subspecies-border lies at 20 degrees South - which happens to be the latitude of the largest salina on Earth (https://en.wikipedia.org/wiki/Salar_de_Uyuni#) - or slightly farther south.

This differs considerably from http://www.isocard.net/images/journal/FILE486198178b052d8.pdf, in which Wheeler (2012) gives the crucial latitude as only 18 degrees South.

However, precise delineation remains elusive, for now.

We need

  • more, and clearer, photographs around the latitude of 20 degrees South, and
  • more information on possible small-scale translocations made by those conserving the species for its valuable wool, but not necessarily respecting the subspecies-distinction.
Posted on 07 February, 2023 16:26 by milewski milewski


Dear Antoni. Thank you for your research. These are very interesting findings. However, it is difficult to say whether it would really be possible to determine the exact boundary of both subspecies based on observations with iNaturalist. The most ideal thing would be to reach out to someone who regularly moves in these areas to try to get additional observations with good pictures from a potential border area of vicugna/mensalis, in one time period. I would also like to know if these subspecies, remarkably similar, can hybridize with each other and in what areas (if there is no exist some natural natural barrier in the potential migration of populations). I think you could contact the relevant curators or administrators to add both subspecies to the Vicuna taxonomy on Inaturalist. But, from the point of view of the complexity of defining the exact boundaries of the ranges of both subspecies, I am not sure if our identifications will be relevant down to the subspecies level in this case.

Posted by michalsloviak over 1 year ago

@michalsloviak Dear Michal, Many thanks for your comment.

Posted by milewski over 1 year ago

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