Commonly Misidentified and Misclassified Species

Mustelids being misidentified is a frequent problem that often leads to myths, false sweeping generalisations about their behaviour, and other harmful misinformation. It is not uncommon for some species to be falsely accused of preying on domestic animals or wildlife, or causing damage to property that was performed by a different mustelid, or an animal from another family entirely. Animals being misidentified can lead to unwarranted stigma and unnecessary killings. Not only can this be harmful for the animals, too many people making false claims can cause biologists and other wildlife experts to discount abnormal sightings or incidents that could be true.

While no one should ever be faulted for not knowing how to identify mustelids, not admitting uncertainly and instead confidently making claims based on impulsive guesses is a whole different matter. Anyone who expresses interest in mustelids should attempt to learn about their most basic differences to help reduce the chance of inadvertently spreading misinformation.

Commonly misidentified species

Some of the misidentifications below may seem absurd to those who are familiar with mustelids or other mentioned animals, but it shows how many different species can potentially be falsely accused of disturbances, attacks, or damage to property. These are just a few cases of mistaken identity we have encountered on social media and organisation websites when it comes to photos, videos, descriptions, and other online content. While most listed are misidentified because of superficial aspects, some were also included due to behavioural or vocal misconceptions.

Mustelids that are misidentified as these other mustelids, or vice versa

Ratel or North American badger for the European badger.

Fisher for the North American marten, ratel, or wolverine.

• North American marten or beech marten for the Eurasian pine marten.

Japanese marten for the Malay weasel.

North American mink for the European mink or a species of otter.

Ferret for the North American mink, European mink, North American polecat, European polecat, European polecat-ferret hybrid, species of stoat, and practically any other mustelid within the subfamily Mustelinae.

Long-tailed weasel for the Eurasian stoat, Haida stoat, or North American stoat.

Tip: When it comes to stoats, keep in mind that the term stoat and short-tailed weasel are referring to either of the same three species. Additionally, in the English language “ermine” is usually a term used to refer to any of the three species of stoats when in their white winter coat or pelt thereof.

Other creatures are also called ermine when sporting a black and white colouration such as certain types of moths, (Spilosoma lubricipeda, tautologically referred to as the white ermine, and the family Yponomeutidae). More detailed information regarding common names for stoats can be found here.

Non-mustelids that are misidentified as these mustelids, or vice versa

Common raccoonsskunks, groundhogs, porcupines, and the Virginia opossum for a species of badger.

• Raccoons, cats, and red foxes for a fisher.

Beavers for a North American mink, European mink, or a species of otter.

Bearswolves, Tasmanian devils, raccoons, and raccoon dogs for a wolverine.

Mongooses, chipmunks, and rats for a species of weasel.

Fossas, civets, cats, and binturongs for a species of marten.

• Civets for a species of ferret-badger.

Seals for a giant otter or sea otter.

Four tips to lessen the chance of misidentifying mustelids

1. It is important to remember that when comes to most mustelids, few in the general public are familiar with them, and merely have a foggy and often overgeneralised idea of what they look like. And when some people see an animal they cannot identify that matches that hazy visualisation of what a mustelid is, they tend to assume the first species that comes to mind. To make matters worse, some mustelid species have been so sensationalised in folk and pop culture, that some people may convince themselves to see trail cam footage of what is clearly a groundhog as a big “ferocious” wolverine or species of badger.

Taking this into account, it is imperative to not assume that every claim regarding the identity of a species is accurate, particularly if those claims are not coming from credible sources or people who are knowledgeable about mustelids. And not surprisingly, with artificial intelligence (AI) generated content from content farms making their way on to animal “facts” websites and other media, there is now an even greater chance of the public being misinformed and misidentifying species.

2. Do not overgeneralise species. Be aware that there is more than one species of badger, marten, otter, weasel, etc. in existence, and that they all have their own unique behaviours, characteristics, range, and vulnerabilities in relation to their respective environments. For instance, just because the beech marten is known to gnaw on the wiring and tubing of automobiles, that does not necessarily mean the Eurasian pine marten, North American marten, or any other marten species are likely to do the same.

3. If you think you saw a particular animal, do a little online research on sites like iNaturalist to learn about that animal’s range and habitat. See if it matches up with where you saw it to rule out other possibilities. You might be surprised to learn that the animal you saw in Ecuador that you thought was a species of stoat is in fact not found in that country, but a similar-looking animal called the long-tailed weasel is.

4. Sometimes people get excited and can leap to conclusions when they think they have spotted an elusive animal. Anecdotally, we have heard some say they thought they saw a weasel dash across a road, only to find out upon closer inspection that it was a chipmunk. This is not to say that it is impossible to see something rare, and unlikely animals have turned up in strange places. But as a general rule of thumb when identifying wildlife, when in doubt, you probably saw the least exciting option.(1)

Commonly misclassified species and their characteristics

Animals that are commonly misclassified or misidentified as mustelids

While misclassifying species is arguably not as harmful as misidentifying them, classifications are important to more easily communicate biological information and draw up protection for species. As with taxonomy, classifications can change due to new genetic evidence, and while the results are not always agreed upon by scientists, the goal is chiefly the same.

Some animals that are misclassified as mustelids tend to be on account of their superficial similarities to weasels or martens. However, in a taxonomical sense, animals are usually not classified by their outward appearance alone. For this reason, even if an animal has an elongated body, rounded ears, short legs, or well-developed anal glands, that does not necessarily mean it is a mustelid or even closely related to one. 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 form their own branch within the superfamily Musteloidea—which is sometimes misleadingly called the “weasel superfamily”, given that the common raccoon, red panda, and many other, mostly non-weasels are included in this branch.

The following families tend to have one or more iconic species that are commonly mistaken for mustelids or vice versa.

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.(2)

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 sometimes 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 resembles a cougar, and the Eastern falanouc has 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, which are hollow bony structures enclosing the middle and inner ear. Mustelids are caniforms and have single-chambered or partially divided auditory bullae.

Herpestidae: Mongooses

Species of mongoose (which include meerkats) may appear weasel-like or marten-like, but they are not mustelids. They are not even closely related.

Characteristics:

• Absence of ear pockets (also known as Henry’s pockets, or more formally referred to as cutaneous marginal pouches) 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, which are hollow bony structures 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 is misclassified as (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.(3) Sometimes skunks are also misleadingly called polecats, which in some cases may be due to people mistaking them for the striped polecat.

As for stink badgers, they were once considered mustelids and related to the European 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.(4)(5)

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.

Muridae: Mice, rats, gerbils, and allies

Many mustelid species continue to be mistaken for rodents. This is most apparent in art, animation, and other media where they are sometimes given buckteeth. Mustelids are not rodents, the majority of them eat rodents.

Characteristics:

• Unlike mustelids, rodents have a single pair of continuously growing incisors in each of the upper and lower jaws and lack canine teeth.

Viverridae: Civets, genets, binturongs, and allies

Members of this family are commonly called civets or genets. Most 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, which are hollow bony structures enclosing the middle and inner ear. Mustelids are caniforms and have single-chambered or partially divided auditory bullae.

References

  1. Miller, Matthew L. 20 August, 2022. A Field Guide to Commonly Misidentified Mammals. Accessed 04 November, 2022.
  2. Flynn, John J., et al. “Whence the red panda?”. Molecular phylogenetics and evolution 17.2 (2000): 190-199.
  3. Dragoo, Jerry W., and Rodney L. Honeycutt. Systematics of mustelid-like carnivores. Journal of Mammalogy 78.2 (1997): 426-443.
  4. 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.
  5. 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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