All members of the order Carnivora fall into one of two sub-orders: Feliformia (cat-like), or Caniformia (dog-like). Outward appearance of carnivora can be deceiving; most people would classify the hyena and aard-wolf as “dog-like”, while the weasels and pole-martens are commonly considered “cat-like”, which they are not.
The Feliformidae are obligate carnivores; that is, they must eat meat to survive, as their body cannot produce one or more nutrients that cannot be found in plants, or that their digestive tracts cannot absorb large amounts of non-animal matter. They are not all hypercarnivorans (meat making up >70% of the diet), however. The order Feliformia includes all of the cats (Felidae), mongooses and meerkats (Herpestidae), hyenas (Hyaenidae), civets and genets (Viverridae), as well as two very small families: the Nandiniidae, which contains only the African palm civet; and the Prionodontidae, which contains the two Asiatic linsangs.
Caniformidae include the seals, sea lions, and walruses (Pinnipedia); true dogs (Canidae); bears (Ursidae); skunks (Mephitidae); badgers, weasels, and otters (Mustelidae); raccoons, coatis, and kinkajous (Procyonidae); and the family containing only the red panda (Ailuridae).
Most Caniformidae (except for the Canidae, interestingly enough) are plantigrade - that is, they walk on all of their podial and tarsal bones on the ground at the same time. This affords greater stability and weight-bearing ability and is helpful when standing your ground or trying to balance in trees.
The Feliformidae (and the true dogs, or Canidae) are almost completely digitigrade - they walk on just their finger and toe bones, and have elongated “heel” bones and Achilles tendons. Digitigrade animals can move much more quickly and quietly than plantigrade animals, and their specialized “heels” allow for spring-type motion, like what you see in cats.
Huge h/t to the ever-awesome Emily Graslie of The Brain Scoop for finding the words to simplify something I’ve wanted to post on for a while ;D Go watch The Brain Scoop and get smart!
More on Tetrapodal Locomotion!
The Brain Scoop
[Wolverine, Walrus] American Animals. Witmer Stone and William Everett Cram, 1902.
[Spotted Hyena, California Sea Lion] The Book of the Animal Kingdom: Mammals. W. Percivall Westell, 1910.
[Black-Footed Ferret, Polar Bear] Quadrupeds of North America. John James Audubon, 1851.
[Kinkajou, Lion] Dictionnaire Universel d’Histoire Naturelle. M. Charles d’Orbigny, 1849.