Mustelids and procyonids generally seem to have horizontal pupils

(writing in progress)
We have seen that Sarcophilus has a vertical slit/slot pupil much like that of a cat, while Gulo – despite having impressive similarities to Sarcophilus – has a categorically different pupil which forms a horizontal slit/slot.

Important in this comparison is that both Sarcophilus and Gulo have small eyes for the sizes of their bodies.
We have also seen that certain diurnal mongooses, which possess large eyes relative to body size, have horizontal slit pupils.
This leads us to the question of which other carnivores, besides Gulo, have horizontal slit pupils despite having small eyes.
The answer seems to be ‘many’.
The ferret has horizontal slit pupils in small eyes, and it belongs to the same family as Gulo: Mustelidae. It is said that weasels are similar in this way. I have yet to find clear photos in the case of the honey badger or otters, but I suspect that all mustelids have horizontal pupils, the main difference among genera being how long the slot is.
Coatis also have horizontal slit pupils, and they belong to the raccoon family, Procyonidae. Another procyonid, the olingo, also has horizontal slit/slot pupils although these are short. I’d like to know the pupil shape in the case of the raccoon but so far no photos have shown this to me.
Although coatis are diurnal, they are like mustelids in having small eyes relative to body size.
So I have more research to do, but the pattern emerging is that many if not all mustelids and many procyonids do indeed have horizontal slit/slot pupils, in contrast to viverrids and felids as well as foxes (e.g. Vulpes, which certainly has a vertical slit pupil).

And I am getting the impression that, in Carnivora, a major correlate with long, horizontal slit/slot pupils is small eyes relative to body size – certain extremely specialised mongooses being the exceptions because they have big eyes.
Altogether, an intriguing topic well beyond the scope of any comparison between Sarcophilus and Gulo; and in a way Sarcophilus is the least interesting part of this topic, not so?
Mustela putorius:
Procyonidae: Nasua nasua:
Procyonidae: Bassaricyon gabbii:
Compare the above mustelids and procyonids with the following viverrid:
Viverridae: Arctogalidia trivirgata:

(writing in progress)

Posted on Σεπτέμβριος 02, 2022 0543 ΠΜ by milewski milewski


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