In stotting its bleeze, the Patagonian mara (Dolichotis patagonum) may be the most ungulate-like rodent on Earth

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The Patagonian mara (Dolichotis patagonum, https://academic.oup.com/mspecies/article/doi/10.2307/0.652.1/2600781?login=false) is a relatively cursorial caviid rodent (https://en.wikipedia.org/wiki/Caviidae), with a body mass of about 10 kg.

Please see https://www.researchgate.net/figure/Photo-of-a-mara-Dolichotis-patagonum-with-some-adaptations-for-running-being-highlighted_fig3_333504431 and https://go.gale.com/ps/i.do?id=GALE%7CA609539093&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=03279383&p=IFME&sw=w&userGroupName=anon%7E9e205385&aty=open+web+entry.

This may be the only rodent on Earth that

• stots (https://en.wikipedia.org/wiki/Stotting) by means of stiff-legged, bouncing locomotion, and
• possesses a bleeze (defined as a dark/pale pattern so bold that it makes the whole figure conspicuous, even at distance, and even when stationary).

The combination of stotting and displaying a large-scale conspicuous pattern on the hindquarters is associated with ruminants, from Ourebia ourebi (about 15 kg, https://www.dreamstime.com/oribioribi-sprinting-across-savannah-slightly-longer-shutters-speed-to-capture-motion-oribi-sprinting-across-image143323292) to Alcelaphus caama (about 130 kg, https://www.flickr.com/photos/neeravbhatt/6191239661/).

Among animals featuring this combination, the Patagonian mara is possibly

• the only rodent, and
• the smallest of all mammals.

(Please also see https://www.argentinat.org/journal/milewski/64011-flags-as-features-of-adaptive-colouration-in-lepus-part-2-other-species-of-semi-arid-north-america#.)

The following show that the bleeze of the Patagonian mara

• is situated on the hindquarters, from the base of the tail to each haunch,
• has a mainly horizontal orientation,
• shows dark/pale contrast, independent of sheen/anti-sheen effects, and
• subsumes but is not contributed to by the tail, which is short and bare.

https://www.inaturalist.org/observations/152145094

https://www.inaturalist.org/observations/149507669

https://www.inaturalist.org/observations/74038522

https://www.inaturalist.org/observations/143733867

The following shows that, in some individuals, there is a whitish patch near each knee (at the junction of flank and hindleg). In posteriolateral view, this extends the bleeze in an anterior direction (https://www.inaturalist.org/observations/51901419).

The following show that the bleeze of the Patagonian mara is conspicuous even when the standing figure is viewed in full profile (https://www.inaturalist.org/observations/116824024 and https://www.inaturalist.org/observations/35690755).

The following suggests that the white band of the bleeze can be flared/erected (https://www.inaturalist.org/observations/131837234).

The following shows the appearance of the bleeze when the animal flees (https://www.inaturalist.org/observations/73664556 and https://www.inaturalist.org/observations/147930616).

The following shows that the bleeze is concealed by sitting, which is a frequently used posture in the Patagonian mara (https://www.inaturalist.org/observations/126838562 and https://www.inaturalist.org/observations/109675491).

The following show the stotting gait of the Patagonian mara:

https://www.debrecensun.hu/local/2023/03/24/the-patagonian-mara-of-the-debrecen-zoo-got-a-partner/

https://www.inaturalist.org/observations/106457844

https://www.alamy.com/patagonian-mara-cavy-dolichotis-patagonum-stotting-valdes-peninsula-chubut-patagonia-argentina-image263028463.html

https://www.mindenpictures.com/stock-photo-patagonian-mara-cavy-dolichotis-patagonum-stotting-valdes-peninsula-naturephotography-image90672455.html

https://www.gettyimages.ie/detail/photo/rabbit-in-patagonia-argentina-royalty-free-image/1331275428?phrase=patagonian+hare&adppopup=true

https://www.alamyimages.fr/cavi-de-patagonie-dolichotis-patagonum-peninsule-de-valdes-site-du-patrimoine-mondial-de-l-unesco-province-de-chubut-patagonie-argentine-image396012030.html?imageid=67D29AC8-2DDD-4730-BA46-8F64B855A9A5&p=1360155&pn=4&searchId=fdf407efb395ee4e1da5818b4f0aac6e&searchtype=0

https://www.alamy.com/stock-photo-patagonian-mara-cavy-dolichotis-patagonum-stotting-valdes-peninsula-86749556.html?imageid=518140A7-DE66-4D56-AC01-B56AB482092B&p=269381&pn=1&searchId=589d9d24beda2dcae20b7ee79d560a38&searchtype=0

The Patagonian mara has long, slender legs for a rodent, and might be described as a 'cavy on high heels'. However, it remains digitigrade (https://en.wikipedia.org/wiki/Digitigrade), not unguligrade (https://en.wikipedia.org/wiki/Ungulate).

The following show the walking gait of the Patagonian mara:

https://www.inaturalist.org/observations/164868054

https://www.inaturalist.org/observations/104542547

https://www.inaturalist.org/observations/62059798

https://www.inaturalist.org/observations/38340582

https://www.shutterstock.com/image-photo/patagonian-mara-dolichotis-patagonum-rodent-genus-1207058716

https://www.shutterstock.com/image-photo/patagonian-mara-dolichotis-patagonum-599052566

https://www.alamyimages.fr/photo-image-mara-de-patagonie-81921558.html?imageid=A36AB68D-A326-4319-8811-EE760D18CF22&p=46571&pn=1&searchId=3f16e8ad5731abf977a4bcd41d46be22&searchtype=0

The following show the similarity in walking gait between the mara and a like-size African bambi, Raphicerus campestris (about 10 kg):

https://www.shutterstock.com/image-photo/patagonia-mara-portrait-while-running-grass-399321796

https://www.alamy.com/stock-photo-steenbok-raphicerus-campestris-walking-south-africa-krueger-national-76132028.html

DISCUSSION

Bambis (ruminants with body mass 15 kg or less) occur in South America. However, all of these depend on cover, and have inconspicuous colouration. The niche for a bambi in open vegetation has been usurped by a rodent, on this continent.

With the possible exception of one species/subspecies of Ourebia (which is marginal to the body mass criterion for bambis, anyway), no bambi on Earth possesses a bleeze.

(Please see https://colombia.inaturalist.org/journal/milewski/70050-the-three-main-types-of-oribi-ourebia-at-a-glance.)

The steenbok possesses a conspicuous white patch on the buttocks. However this qualifies as a flag rather than a bleeze, because it is

• located relatively ventrally, where it is normally out of sight,
• hidden by slight hunching of the sacrum (https://www.inaturalist.org/observations/59156961), and
• only raised and flared in alarm (https://www.inaturalist.org/journal/milewski/70293-the-bambis-part-9-bleezes-flags-and-semets-in-the-bovid-genus-raphicerus#).

Furthermore, the steenbok does not stot.

Aspects of the Patagonian mara that are evolutionarily convergent with bovid bambis include

• extremely large eyes, adapted for good vision by day,
• hue-differentiation in the ground-colour
• monogamy, and
• precociality at birth.

However, there is negligible convergence with bovid bambis in

• number of offspring per birth,
• dentition,
• anatomy and function of the stomach,
• cud-chewing (the Patagonian mara is instead coprophagous),
• diminution of the faecal pellets (compare https://www.inaturalist.org/observations/114536300 with https://www.inaturalist.org/observations/76872272 and https://www.inaturalist.org/observations/106239384 and https://www.inaturalist.org/observations/96703224),
• form of the claws, and
• form and mobility of the ear pinnae.

in view of the limited convergence between the Patagonian mara and ungulates, its possession of a well-developed bleeze is surprising. In displaying this conspicuous pattern, particularly by stotting, it outdoes its bovid counterparts - despite being otherwise only superficially ungulate-like.

Publicado el junio 5, 2023 12:39 MAÑANA por milewski