Skunks of the World: Hog-nosed Skunks

American hog-nosed skunk

There are, perhaps surprisingly, at least five different species of skunk living in the US. In fairness, two of them - the spotted skunks - are so similar to one another that it took genetic tests in the 1990s to prove they were more than subspecies, while the striped and hooded skunks are at least superficially similar as well. The fifth one is the American hog-nosed skunk (Conepatus leuconotus) and it's neither striped nor spotted.

If it's less familiar than the others, even to many Americans, that may be because it's only found in the southwest. It is common across Mexico, and also lives across Central America as far south as northern Nicaragua, but in the US it's restricted to Arizona, New Mexico, and Texas. Even here, it doesn't inhabit the whole region, being found in only certain parts of those states and avoiding, for example, both the harsher deserts and dense woodland. Although it does live in some tropical habitats at the far southern end of its range, its preference is instead for grassland and mesquite scrub, often with plenty of acacia thorn bushes. 

The precise range it inhabits may also have changed in recent years. Many online sources, for instance, show the animal as still living in southern Colorado and the western end of the Oklahoma panhandle, but, in reality, none have apparently been seen that far north since 1933. Populations in Texas have also declined, with them vanishing altogether from the eastern parts of the state. On the other hand, a new population may have become established in the Grand Canyon, where the skunks were previously absent, and they're probably common enough in Mexico.

Physically, the hog-nosed skunk is similar in size to the striped skunk, but with a stockier build and a shorter tail. It is also known as the "white-backed skunk" because of its white back, unbroken by any black stripes or similar patterns - the animal is simply white above and black below. Besides the rather obvious lack of stripes, another distinguishing feature is the lack of a white spot or stripe on the upper snout. There is some indication that the white back may be more striking in populations living in more open habitats, perhaps because the implied warning is more useful where it is clearly visible from a distance.

The hog-nosed species is so-named because of the comparatively large and broad tip to its nose, although this is clearly well short of what you'd expect on an actual hog. Nonetheless, it uses this in a similar manner to pigs, rooting around in the ground and under rocks. In its case, it's looking for insects and grubs, something that the claws on its muscular forelegs also help with. Like most skunks, they will eat pretty much anything, including plant matter and meat from larger animals, but insects form a larger part of their diet than they do for striped or spotted skunks, and they are willing to spend hours looking for them if they get the chance.

They are primarily nocturnal, although daytime activity is not especially rare. Like other skunks, they are solitary, but they don't seem to be territorial, overlapping their home range with others of their species, even if they are of the same sex. Having said which, males occupy areas three times larger than females do, apparently because they want to meet as many members of the opposite sex as possible, while the females just want somewhere with a good food supply and somewhere nice to sleep. 

Like most skunks, it would rather not spray if it doesn't have to. Faced with a potential predator, its first inclination is to run away and hide. Stands of pricky pear cactuses are apparently a popular choice here, although, on rare occasions, they have been seen to climb up a tree. If this isn't an option, they will stand their ground, and may try to make themselves look bigger by standing up on their hind legs, and taking a few steps forward before thumping down on their forefeet and letting out a loud hiss. If even that fails to make their opponent think twice, they stamp on the ground and lay their tail flat against their backs before attacking with their spray, and, if necessary, a nasty bite. The spray has two of the same primary components as striped skunk spray, although a third major component is missing, and there are some differences in minor chemicals that subtly alter the aroma (for all that that matters).

At least in the US, the species breeds in February and March, but they are capable of sexual activity throughout the year, so this might be different further south. Litters are small, with typically no more than three kits, and singletons being common; they are born after a two-month pregnancy and leave home at around six months old.

Contrary to the more common trend in recent decades, the American hog-nosed skunk was thought to represent two separate species through the 20th century, but research in 2003 showed that they weren't even distinct subspecies. Thus, many older sources refer to the animal as C. mesoleucus, with the current scientific name reserved only for those animals living along the west coast of the Gulf of Mexico. Although there was once some confusion around its more southerly relatives, too, they have been agreed to represent (at most) three species since the 1960s. More closely related to one another than to the "American" species, probably diverging just after North and South America first joined up around 5 million years ago.

Striped hog-nosed skunk

While the most distinctive feature of the "American" species is its lack of stripes (or single, very broad, white stripe, depending on how you look at it) this is obviously not true of the striped hog-nosed skunk (Conepatus semistriatus). This also lacks the white spot on the snout, and has small, but pig-like, nose for which the genus is named, but it has two white stripes along the back, separated by a black stripe down the middle. 

It lives from southern Mexico through Central America into Venezuela and Colombia and down the western side of South America as far as northern Peru. An isolated population also lives in eastern Brazil, separated from the rest of the species by the Amazon basin. This may sound odd, but until one was photographed in Panama, it was also thought that the Mexican/Central American populations were also separated from the South American ones. What's probably happened here is that the species was more widespread during the Ice Ages, but the expansion of tropical forests at the end of that time split the Brazilian population off and it hasn't yet had time to evolve into an entirely separate species.

This is because, like its more northerly relative, the striped species prefers grasslands and scrub as habitat, although it is also common in sparse woodland and stands of palm trees. While it has been spotted in denser Brazilian forest in recent years, this is likely due to a lack of alternatives as human development continues in the region, forcing them into habitat that they'd normally avoid.

In most respects, their habits seem similar to those of the "American" species, although they are, perhaps, more thoroughly nocturnal and, while they do dig burrows in which to sleep, they may be less inclined to digging in general - perhaps with a less insect-based diet.

Molina's hog-nosed skunk

Further south, we come to Molina's hog-nosed skunk (Conepatus chinga), named for the Jesuit priest and polymath who gave it its scientific name in 1782. It lives through much of mid-South America, from southern Peru, Bolivia, and Brazil in the north, through Paraguay and Uruguay into the more habitable parts of northern Chile and Argentina. It is slightly smaller than the striped species, contradicting Bergmann's Rule that animals in a given group should get larger as one approaches the poles. In general, though, it looks much the same, but with a variable coat pattern that often has a brown or even reddish background over the parts of the body one would expect to be black.

Like its relatives, Molina's species prefers open terrain, ranging from savannah in the north to cold steppelands in the south. It also has a similar diet, preferring invertebrates, with beetles and spiders apparently being favoured foods. Living outside the tropics, such food can be in short supply during the winter months, when its wider omnivory becomes more obvious as it eats more small mammals, birds, lizards, and frogs. They prefer to sleep in burrows during the day, whether they have dug them themselves or stolen them from other animals, but may use above-ground shelters where the ground is too rocky for easy digging. Where possible, dens are likely to be in woodland or in rock piles at the bottom of cliffs, even if the skunks forage for food in more open grassland.

Individuals occupy much larger home ranges than the other hog-nosed species. Females have been reported to occupy an average area of 120 hectares (300 acres) each, while males occupy areas at least twice that size (roughly one square mile). This may be due to a greater difficulty in finding suitable food, since they seem to spend more time searching for it than related species do.

Humboldt's hog-nosed skunk

The same authors that recommended reducing the American hog-nosed skunk from two species to one also recommended merging the two most southerly species of the genus. In this case, however, the evidence is regarded as less clear-cut, and at least some current sources keep the two separate, thus maintaining Humboldt's hog-nosed skunk (Conepatus humboldtii) as a distinct species. Looking very similar to Molina's species, it is found only in Patagonia, across southern Argentina and Chile as far as - but not beyond - the Straits of Magellan. 

It seems to be less of a habitat specialist than the more northerly species, being more willing to live in wooded areas as well as grassland. They seem less keen on digging for themselves, denning in pre-existing spaces where possible, such as hollow trees, shallow caves, and even the spaces beneath log piles and inhabited buildings. While they prefer to prey on invertebrates such as beetles, crickets, and spiders, they consume a higher proportion of carrion than their kin, especially during the winter and also feed at human refuse piles. Perhaps because of the cold nights, they are more crepuscular than nocturnal and are often seen during the day as winter approaches - likely spending more time searching for food so that they can build their reserves up for months when heavy snowfall may make foraging impossible.

With that, I have covered every species of skunk from Canada to the edge of the Antarctic Ocean and included everything that would have been considered a skunk for most of the 20th century. But it turns out that the animals we actually call "skunks" are not the only members of the skunk family as we now understand it. So, to complete the survey of that family, I will have to head somewhere else entirely...

[Photos by Juan Cruzado Cortés, Washington L.S. Vieira, Enrique González, and "Payayita", from Wikimedia Commons.]