M8 Predation/Feeding Modes

Topic

Predation modes combine a predator's locomotor, sensory, and cognitive capabilities, with each mode solving the problem of capturing prey in a distinct way.

Among these locomotor capabilities, the high-speed pursuit practiced by the cheetah maximizes the predator's peak speed—reaching up to thirty meters per second—yet this speed is constrained by hyperthermia: the body heat generated during the sprint exceeds the cheetah's ability to dissipate it, forcing the animal to abandon the chase after a run of only twenty to thirty seconds.

In contrast to this brief, maximum-speed pursuit, African wild dogs prioritize endurance: they maintain a more moderate speed—around ten meters per second—over distances of several kilometers, far exceeding what a cheetah could sustain; this minimizes the energy cost of the prolonged chase while maximizing the exhaustion of the pursued prey.

A third method of capturing prey is the ambush, which—rather than maximizing sustained speed—maximizes the initial acceleration of the attack and the force of impact upon contact with the prey.

At the moment of capture, a portion of that impact force is concentrated into bite force, which depends on the mechanical advantage provided by the jaw acting as a lever system: the greater the distance between the jaw muscle's insertion point and the jaw's pivot point—relative to the distance between that pivot point and the point of the bite—the greater the force the predator can exert on the prey at the bite site. A predator's cognitive and social capabilities come into play more directly during cooperative pack hunting, which increases the likelihood of capturing large prey that a single individual could not take down alone; this probability of a successful group capture rises exponentially with both the number of participating hunters and the relative speed between predator and prey.

Underlying the very decision to pursue, ambush, or hunt specific prey in a group is the predator's cognitive ability to assess whether that prey is worth the effort: a predator includes a prey item in its diet if—and only if—the net energy value of capturing it exceeds the average rate of net energy the predator could otherwise obtain in its habitat. This same logic predicts that a predator living in a prey-rich habitat becomes more selective, rejecting low-energy prey, whereas one in a resource-poor habitat becomes less selective, accepting almost any available prey—demonstrating the very cognitive capacity with which this description of predation and feeding strategies began.

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