The teardrop muzzle of a cheetah or puma, the creamy chest crescent of a moon bear, the bold black-and-white complexion of a European badger, the eyeshadow of a meerkat: seen head-on, your average carnivore's appearance often lands on the striking side of the spectrum.

A team of scientists recently took a close look at those, well, looks – specifically, the facial and chest (aka anterior) patterns of a grand, globe-spanning lineup of terrestrial carnivores – to explore possible explanations for their evolution.

Their study, published last month in Behavioral Ecology & Sociobiology, analysed photographs of 164 sharp-toothed mammals from across six families: the canids (dogs), felids (cats), ursids (bears), mustelids (weasels and kin), viverrids (civets and kin) and herpestids (mongooses). (The hyenids missed the cut due to the fact that there are only four hyena species – too few to effectively compare and contrast under the study's approach.)

Within each carnivore family, the researchers came up with scores for the complexity and contrast of facial and chest colour patterns, and assessed these against a slew of independent variables: from geographic overlap (sympatry) between related species to diet and relative levels of sociality. Those factors were chosen in order to explore several hypotheses linking the evolution of anterior fur markings with particular habits.

Certain findings seemed to square with some prevailing ideas. The notion that more social carnivores might sport more complex frontal patterns – perhaps to enforce individual recognition within the group – jibed with the results for the facial markings of mongooses and the chest markings of dogs.

The markings sported by meerkats and other mongooses might play a role in helping members of a group recognise each other. Image: Pixabay

Meanwhile, the researchers weren't exactly surprised to find a correlation between complex, high-contrast facial pizzazz in mustelids such as the zorilla and the possession of sprayable anal musk: as in skunks, such flashy markings could at least partly serve as a visual warning to potential predators that this critter comes armed and loaded.

Among the weasel crew as well as the viverrids and mongooses, facial pattern also seemed to be associated (in somewhat different ways) with pugnacity. Many carnivores with striped faces hole up in burrows or dens, and it's possible their conspicuous markings direct a don't-even-try-it message straight at potential antagonists as the carnivore in question backs into its lair.

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Among weasels, high-contrast markings might carry a back-off message. Image: USFWS Mountain-Prairie/Flickr

For members of both the civet and mongoose families, a more complex facial pattern tended to square with a diet skewed towards mammals – possibly because the markings help conceal the carnivore as it stalks such especially keen-sighted prey.

Among the bears, the study found species that significantly overlapped in range with other ursids tended to show less variation in facial contrast. Perhaps, the researchers speculated, that helps bears more easily recognize others of their own kind. But the relatively small number of bear species (eight) makes it tough to draw firm conclusions. Only one bear exists in complete isolation from others across its entire range: the spectacled bear, the only South American ursid and, incidentally, notable for its fancy face.

South America's spectacled (or Andean) bear is the only one of the bear bunch with distinctive facial markings. Image: Amy_Mac_82/Flickr

And the cats? Well, they lived up to their whole independent, uncooperative image by offering no statistically significant results in the study: no positive associations between face or chest flourishes and the particular lifestyles under analysis.

The authors suggest their inquiry, boiled down, mostly underscores the probability that carnivore face and chest patterns evolve for multiple purposes, and that it's risky to "assum[e] that similar markings serve similar functions even within a single taxonomic order".

The lead author of the study, Tim Caro of the University of California, Davis, told Science’s Michael Price that another group of mammals well known for its splendid array of face and chest markings definitely warrants this sort of investigation. "The holy grail in colouration is primates," he said. "We're just beginning to lay the groundwork that will get us there."