Animals Mistaken for Mustelids

Animals that are commonly misidentified or misclassified as 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 an 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. In fact, given the diverse scale of the animal kingdom, some of these features are not uncommon or very distinctive.

Several animals that are frequently mistaken for mustelids actually form their own branch within the superfamily Musteloidea—which is sometimes misleadingly called the “weasel superfamily”, given raccoons, red pandas, and many other non-weasels are included in this branch.

Ailuridae: Red 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 specialised 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 are 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) Sometimes skunks are also erroneously called polecats because of their similar appearance to the striped polecat. As for stink badgers, they were once considered mustelids and related to the Eurasian badger, but recent DNA analysis indicated they share more in common with skunks, and as a result, they too were 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 is 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. Badgers.org.uk. 2012. Badger Pages: The stink badgers. Archived from the original on 5 May 2012. Accessed 4 September 2020.

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