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, is a relatively cursorial caviid rodent (, with a body mass of about 10 kg.

Please see and

This may be the only rodent on Earth that

  • stots ( 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, to Alcelaphus caama (about 130 kg,

Among animals featuring this combination, the Patagonian mara is possibly

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

(Please also see

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.

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 (

The following show that the bleeze of the Patagonian mara is conspicuous even when the standing figure is viewed in full profile ( and

The following suggests that the white band of the bleeze can be flared/erected (

The following shows the appearance of the bleeze when the animal flees ( and

The following shows that the bleeze is concealed by sitting, which is a frequently used posture in the Patagonian mara ( and

The following show the stotting gait of the Patagonian mara:

The Patagonian mara has long, slender legs for a rodent, and might be described as a 'cavy on high heels'. However, it remains digitigrade (, not unguligrade (

The following show the walking gait of the Patagonian mara:

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


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

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

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

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.

Posted on June 05, 2023 12:39 AM by milewski milewski



Have you ever seen a photo showing stotting in Cervus canadensis?

Conceptual framework:

Cervus elaphus is well-known to stot, and is said to be so closely-related to C. elaphus that they may be a single species/superspecies.

However, it occurred to me for the first time today that I have never seen stotting in C. canadensis, which instead reacts to attacks by Canis lupus by something approaching a 'proud trot' with the muzzle held conspicuously high (

If this is a real difference, it might be further evidence that C. canadensis is more different from C. elaphus than was realised in the past.

Your thoughts?

I suspect that the following shows stotting in C. canadensis:

Posted by milewski about 1 year ago

Clear illustration of auricular flags and buccal semet in Cervus canadensis:

Posted by milewski about 1 year ago

Cervus elaphus and Cervus canadensis may indeed be conspecific, after all, there's zero problem when they hybridise. The definition of species in the genus Cervus is as trivial as the genus Canis.

Posted by paradoxornithidae about 1 year ago

Interestingly, Elaphurus can readily hybridise with Cervus without any fertility complications, producing seemingly normal offspring when crossed, with the hybrids being fully fertile. It's reasonable to assume Cervids are over-split by taxonomists.


Posted by paradoxornithidae about 1 year ago

@paradoxornithidae @dejong


Conspicuous colouration is unusual in rodents, for the obvious reason that these mammals tend to rely on hiding at, or under, ground level.

We can expect conspicuous colouration to be unusual also in primates, for different reasons. This order of mammals tends to be arboreal.

So, are there any examples of bleezes on the hindquarters of primates, particularly those forms most adapted to terrestrial activity?

One possible candidate is Nasalis larvatus (, which is often seen on the ground among mangroves.

In mature males of N. larvatus, the hindquarters have a conspicuous pattern ( and and

The main element of this pattern is the tail, but its whitish extends to the rump, where there is a remarkably sharp border with the brown of the back.

The conspicuous pattern in N. larvatus is plausibly more effective when the figure is sitting arboreally (

Another possible candidate is Erythrocebus (, the most terrestrial monkey on Earth.

As in N. larvatus, the conspicuous pattern is restricted to mature males, and consists mainly of whitish pelage. However, unlike N. larvatus, the pale surface is not on the tail and rump, but instead on the hindlegs, extending to the buttocks.

So, do these monkeys possess a bleeze, comparable to that of Dolichotis patagonum?

My verdict is no, because a) the pattern in the rodent is consistent with anti-predator display, whereas those in the monkeys are instead consistent with social/sexual display, and b) the patterns are not as conspicuous in the monkeys as in the rodent, partly because the environments of the monkeys tend to be cluttered with vegetation, and partly because there is no dark element on the hindquarters in Erythrocebus, limiting the pale/dark contrast.

I would, therefore, tentatively describe the patterns in these primates as a caudopygal flag in N. larvatus, and a fibuloischial flag in Erythrocebus.

(For a reminder of the appearance of a fibular flag, please see the comment above titled 'Fibular flag in Alces alces.)

Posted by milewski about 1 year ago

Interesting that the Proboscis monkey of Kalimantan/Borneo has such a pattern

Posted by paradoxornithidae about 1 year ago

Aren't members of Papionini (Baboons) also quite terrestrial?

Posted by paradoxornithidae about 1 year ago

Erythrocebus is more specialised for terrestriality than is any species of Papio. Theropithecus is as terrestrial as Erythrocebus while foraging, but remains dependent on climbing in cliffs.

No species of Papio or Theropithecus has a conspicuous pattern, in terms of dark/pale contrast, on the hindquarters that would be a candidate for a bleeze (

Posted by milewski about 1 year ago


The closest I have found to a dark/pale contrast on the hindquarters of a papionin is the following, of mature male Papio hamadryas:

The pink does not count w.r.t. my definitions of bleeze, because it is conspicuous by means of hue, not tone. It can be considered a flag, intraspecifically (because papionins see this hue).

Posted by milewski about 1 year ago

Dolichotis patagonum has body mass 8-9 kg.

For comparison, here are the body masses of other large rodents, in decreasing order:

Hydrochoerus hydrochaeris 60 kg (
Castor fiber 25 kg (
Myocastor coypus 13 kg (
Erethizon dorsatum 5 kg (
Coendou prehensilis 5 kg (
Lagostomus maximus 4 kg (
Cavia aperea 0.5 kg (

Posted by milewski about 1 year ago

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