Thirty-five million years of evolution have honed Felis concolor into an almost perfect predator. The cougar's keen senses, muscular body, and remarkable adaptability make it ideally suited for a predatory existence. Because they are the most exclusive of meat-eaters, almost every feature of a cat's body is related to the way it detects and catches its prey.
DETECTING PREY
The big cats use all of their senses in their ongoing search for prey. When the Florida panther stepped in front of my truck that night in the Everglades, and the eerie glint of its eyes flashed back at me, I was witness to a universal feature of feline legend. But the eyes of a cat are not windows to the fires of Hell, as witch hunters in the Middle Ages believed;(2) they are actually the marvelous adaptation of a nocturnal hunter
Cats have extraordinary vision. The eyeball, pupil, and lens are proportionately larger than other carnivores. The eyes of a domestic cat are only slightly smaller than those of humans, but the cat can open its pupil to a maximum area three times larger than humans can;(3) this increases light-gathering ability and enhances night vision. Cougars are both nocturnal and crepuscular (active during the twilight hours of dawn and dusk). As a result, their eyes are proportionately smaller than the mostly nocturnal lynx, making pumas suited to hunting both in daylight and at night.(4, 5) The amount of light entering the eyeball is controlled by the pupil, and the pupil in smaller cats is elliptical.
While a cougar's extraordinary vision seems to give it a distinct advantage over its prey, nature has a way of compensating for advantages. In humans, the high concentration of cones in our eyes allows us to resolve (discern) visual detail in daylight, while the low concentration of rods inhibits our ability to resolve detail in low light. This resolving power is called visual acuity. While the concentration of rods and the presence of a tapetum has increased the cat's sensitivity to low light, it has sacrificed visual acuity. Rods do not allow for much discrimination between light wavelengths, and the tapetum further blurs the image the cat sees. As a result, cats' vision at night is six times better than that of humans, but humans have better visual acuity.(1, 2, 3)
Further, in prey species such as deer, the eyes are mounted on the side of their head. This arrangement does not allow binocular vision but does increase the total field of view and the ability to detect predators.(7) Cats also have a heightened sensitivity to movement, and biologists believe that it is the movement of prey that triggers the puma to attack. This may explain why prey typically will "freeze" after detecting a predator.(6) In the world of predator and prey, there seems to be a defense for every offense.
Although little research has been done on hearing in cougars, it is known that domestic cats can detect their prey by sound as well as sight. They can hear frequencies in the ultrasonic range and are able to move their small, rounded ears together or independently to isolate these sounds. It is also believed that an enlarged auditory bullae (the portion of the skull surrounding the middle ear) may enhance a cat's sensitivity to certain sounds.(1, 3, 8)
Experts speculate that in most cats, vision and hearing are important for hunting, while smell plays a more active role in social behavior) In Chapter Three: Cougars at Home it was explained that pumas have a special olfactory organ in the roof of their mouth that is employed during a flehman response, presumably to determine the reproductive condition of a female.(11) Cougars also seem to share their domestic cousin's attraction to catnip.(8, 12) Smell, a well-developed feline sense, is not primarily used in hunting. However, "We probably underestimate how much cougars use their sense of smell," says Fred Lindzey, "I once saw a captive male picking up the scent of a deer." Lindzey thinks cougars probably do not use their sense of smell in hunting, but can generally use it to determine whether deer are in the area.(9) Bogue and Ferrari observed a six-month-old puma kitten follow a scent trail they laid down through undergrowth with a piece of hide from a freshly killed deer.(10) Nonetheless, dogs' sense of smell is much more highly developed. The longer muzzle of a dog boasts almost 50 square inches of olfactory cells to the cat's 6 square inches, and 5 percent of canine brain volume is committed to its sense of smell, compared to 3 percent in cats.(1)
Cats have an acute sense of touch, particularly with the tip of their nose, toes, and paws.(8) A cat's whiskers are specially adapted as tactile sensors; during prey capture they are extended like a net in front of the mouth so the cat can determine exactly where the prey is to accurately inflict the killing bite.(13) Barry Lopez tells of one biologist who believes that a cougar's paws are so sensitive that when it attacks deer in pitch black it can determine the location of the head by instantly sensing the direction its hair is growing.(14)
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