As befits animals toward the upper portions of the food web, carnivores tend to have smaller population numbers than herbivores. They also tend to have fewer kinds, perhaps because there are fewer prey-oriented ecological niches than there are niches for herbivores and omnivores—the tactics required to take one particular kind of small, nocturnal mouse likely will suffice for a number of other kinds of small, nocturnal mice. Thus there is no necessity for a one-to-one relationship between predator and prey. There are exceptions, however, where predators have evolved considerable reliance on a single prey type (e.g., Black-footed Ferret on prairie dogs).
There are about 15 families and 271 species of living carnivores. Carnivores are characterized by possession of a carnassial (shearing) pair of teeth which consist of P4/m1, rather than by diet (the Greater Panda, for example, is an herbivore), though most are indeed meat eaters though many also will take vegetal material. (Keep in mind that many non-Carnivora taxa eat or are even entirely dependent on animal protein. For the purposes of this section, "carnivore" will refer to members of the Carnivora.) All carnivores also have well developed canine teeth. Carnivores dependent on capture of prey (rather than being omnivorous or herbivorous) have a glenoid fossa (the socket of the squamosal into which the dentary fits) that partially surrounds the condyloid process of the dentary, providing support during powerful biting and pretty much limiting movement to the vertical plane.
Most carnivores have an os baculum (penis bone). One suggestion for its presence is that it allows prolonged copulation in forms that have induced ovulation (that is, forms that ovulate in response to copulation rather than spontaneously).
The centrale, scaphoid, and lunar carpals of the wrist are fused into a single element, the scapholunar. Generally, the clavicle is reduced, allowing increased stride and, where contact is lost between shoulder girdle and sternum, allowing the forelimb/girdle complex to act as a shock absorber (with no contact between forelimb/girdle and the remainder of the skeleton, the forelimb shock is taken up entirely by muscles). Claws are characteristic of carnivores (vestigial in at least one) and, in most felids and some viverrids, may be retractile; that is, the terminal phalanx is able to rotate to the point that the claw doesn't meet the ground.
Carnivores that tend to capture active prey are digitigrade; others, such as bears and some procyonids, are plantigrade. Except for the pinnipeds and the characters noted above, the postcranial skeleton tends to be primitive (that is, few losses or fusions).
Most carnivores have anal glands that produce odiferous secretions for communication and, in the case of skunks, protection. Members of the weasel (Mustelidae) and skunk (Mephitidae) families (weasels, otters, badgers, skunks, etc.) have such glands particularly well developed compared to felids and canids. Ursids and some procyonids lack them.
The two living suborders, Feliformia and Caniformia, are separated
by details of the auditory bullae, among other characters. In the Feliformia, the bulla is formed by the tympanic and endotympanic bones, and there is a septum within the bulla where the two bones
join. The tympanic forms almost the entire bulla in caniforms, however, and there is no septum.
Bobcat skull sectioned so as to reveal the septum within the bulla. On the left, the sectioning has broken away the lateral side of the septum, leaving the medial portion. On the right, the section is farther posterior and the septum can be seen within the bullar cavity.
The suborder Feliformia includes the families Felidae (cats), Viverridae (civets and kin), Eupleridae (fossa and relatives), Nandiniidae (palm civet), Herpestidae (mongooses), and Hyaenidae (hyaenas). Only the Felidae is native to the New World, though one extinct hyaenid occurred.
As a group, the cats are highly carnivorous, relying hardly at all on plant material for food. This carnivory is revealed in part by the highly sectorial nature of the teeth, lacking the crushing features seen, for example, in the canids. All are relatively short-snouted and with the carnassial teeth close to the jaw articulation; this configuration confers power to both the front of the jaw and to the carnassial region. Tooth reduction has gone further in this family than others (to 28 or 30 teeth total).
Various cats have specialized for different kinds of prey, including fish and birds, but the New World natives feed primarily on mammals. Division of prey among the different taxa is largely on the basis of size. The living felids (and probably extinct forms as well) are stealth hunters, either stalking their prey or lying in ambush until the prey is close enough for a lunge or for a short chase. In line with these tactics, most have spots or stripes that tend to blend into the background and to break up the outline of the animal. None is adapted for long term cursorial activity. Even the Cheetah, the fastest cursorial mammal, can sustain its speed only briefly and soon gives up if the prey is not taken quickly.
The family Felidae has attracted more than its share of splitters and lumpers. Some recent workers have recognized as many as 18 genera, while others have recognized as few as two. Following Wilson and Reeder (2005), we'll recognized the genera in our region as Felis (House Cat), Leopardus (including the Ocelot and Margay), Lynx (Bobcat and Lynx), Panthera (Jaguar), and Puma (Mountain Lion). Felis encompasses the "small" cats; Lynx the short-tailed cats with reduced dentition (28 teeth); Panthera, the "big" cats; Puma, only the Mountain Lion. In the Old World, the Cheetah is recognized as Acinonyx.
Regionally, we have three native felids: P. concolor, the Mountain Lion; L. rufus, the Bobcat; and P. onca, the Jaguar. The latter is marginal in our area, though it has been photographed in the Peloncillo Mountains of southwestern New Mexico in this decade and there are older records to central New Mexico.
Mountain Lions prey primarily on deer in our area, with the "take" estimated at about one deer per week for an average adult. Particularly in desert areas, home ranges must be large in order to have sufficient prey. Ranges of up to 50 square kilometers are known, often of great linear extent. Mountain Lions have denned in the Franklin Mountains in the El Paso area, and generally these animals occur in rough country with ample cover. A few years ago, a young animal was killed in the back yard of a house near the Franklins as it attempted to attack a dog; an autopsy showed an emaciated body and an empty gut.
Bobcats are common in our region, though again mostly in broken country. As with their larger relative, their ecological range is from desert to montane forests. They feed on smaller prey on average than Mountain Lions, with lagomorphs particularly taking the hits. Territories tend to be around 2 to 3 square miles.
The Bobcat skull is fairly typical of cat skulls except for having only two upper premolars instead of the usual three found in the others.
Last Update: 21 Mar 2009