Animals Mistaken for Mustelids

It is not uncommon for many animals to be mistaken for weasels or other mustelids, based on their superficial similarities. The complicated truth is, in a biological sense, animals are not classified by their outward appearance alone. For this reason, even if an animal has mustelid-like features (e.g., elongated body, rounded ears, short legs, or even well-developed anal glands), that does not necessarily mean it is a mustelid, or even closely related to one. Some animals that are frequently mistaken for mustelids in fact form their own branch within the superfamily Musteloideawhich is sometimes misleadingly called the “weasel superfamily”, given raccoons, red pandas and other non-weasels are included in this branch.

AiluridaeRed panda

Although this sole species is basal to both mustelids and procyonids (raccoons), the red panda forms its own unique family branch, Ailurids.(1)

CHARACTERISTICS:

Massive, rounded head shaped by jaw muscles evolved to consume a specialized vegan diet of bamboo that mustelids would never touch.

Tail has rings, a pattern not found in mustelids.

Eupleridae: Malagasy carnivores

A family endemic to Madagascar, closely related to Herpestidae. They may look more cat-like than weasel, but they are often mistaken for weasels because of their rounded ears.

CHARACTERISTICS:

Adapted to a diversity of niches entirely different than those of mustelids. For example, the fossa (Cryptoprocta ferox) resembles a cougar and the fanaloucs (Eupleres goudotii, E. major) have narrow jaws and flat teeth for a diet based on worms, slugs and larvae. Most bear more resemblance to members of Herpestidae and Viverridae (see below).

Vertically slit- or rectangular pupils.

Rough tongue, as in all feliforms.

Skull identification: All feliforms have double-chambered auditory bullae, capsules enclosing the middle and inner ear. Mustelids are caniforms and have single-chambered or partially divided auditory bullae.

HerpestidaeMongooses

They look similar in ways, but species of mongoose (which include meerkats) are not mustelids. They are not even closely related.

CHARACTERISTICS:

Absence of ear pockets on the outermost ridge of the ear rims.

The muzzle is more pointy.

Pupils are horizontal and rectangular (visible in the species with brightly coloured eyes). Most mustelids have horizontal slit pupils, but the mongooses’ pupils look- and function like those of horses, sheep and goats, enabling them to see their surroundings in wide-angle vision.

Digitgrade. Unlike mustelids, some species have four digits instead of five.

The limbs are thin and bony in comparison to the body.

When standing on their hind limbs they will do so at the very tip of their digits, using their strong tails for balance.

Rough tongue, as in all feliforms.

Skull identification: All feliforms have double-chambered auditory bullae, capsules enclosing the middle and inner ear. Mustelids are caniforms and have single-chambered or partially divided auditory bullae.

Mephitidae: Skunks and stink badgers

Perhaps the most common species that’s superficially mistaken for (or still believed to be) mustelids, are skunks. Skunks were formerly classified as a subfamily of Mustelidae, but due to genetic evidence, in the late 1990s they were given their own classification, Mephitidae.(2) Similarly, the stink badger was once considered to be related to the Eurasian badger, but recent DNA analysis indicated they share more in common with skunks, and as a result they were also placed in the family Mephitidae.(3)(4)

CHARACTERISTICS:

 Stocky, barrel-like build, even heavier set than the badgers and the wolverine.

Anal scent glands are even more developed as a weapon to deter predators, producing a foul liquid acid that can cause temporary blindness.

Skunks: The tail is extremely bushy with very long, feathery hairs.

Stink badgers: The tail is reduced to a stump.

ViverridaeCivets, genets, binturongs and allies

Members of the family Viverridae are commonly called civets or genets. Many species within this family share weasel-like to marten-like characteristics, and are understandably mistaken for mustelids.

CHARACTERISTICS:

Vertically slit pupils

The nose is fleshy, rounded or square in shape with a very deep philtrum (mid-line grove), as if it’s split.

The ears are deep and tall rather than flat and broad.

Fleshy paw pads in unique arrangement and shape that are always bare, sometimes with a padded heel.

Rough tongue, as in all feliforms.

Skull identification: All feliforms have double-chambered auditory bullae, capsules enclosing the middle and inner ear. Mustelids are caniforms and have single-chambered or partially divided auditory bullae.

References

  1. Flynn, John J., et al. “Whence the red panda?.” Molecular phylogenetics and evolution 17.2 (2000): 190-199.
  2. Dragoo, Jerry W., and Rodney L. Honeycutt. “Systematics of mustelid-like carnivores.Journal of Mammalogy 78.2 (1997): 426-443.
  3. Koepfli, Klaus-Peter, et al. “Multigene phylogeny of the Mustelidae: resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation.” BMC biology 6.1 (2008): 10.
  4. Jackson, S. 2012. Badger Pages: The stink badgers Badgers.org.uk. Archived from the original on 5 May 2012. Retrieved 4 September 2020.

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