Pursuit predation
Pursuit predation is a form of predation in which predators actively give chase to their prey, either solitarily or as a group. It is an alternate predation strategy to ambush predation — pursuit predators rely on superior speed, endurance and/or teamwork to seize the prey, while ambush predators use concealment, luring, exploiting of surroundings and the element of surprise to capture the prey. While the two patterns of predation are not mutually exclusive, morphological differences in an organism's body plan can create an evolutionary bias favoring either type of predation.
Pursuit predation is typically observed in carnivorous species within the kingdom Animalia, such as cheetahs, lions, wolves and early Homo species. The chase can be initiated either by the predator, or by the prey if it is alerted to a predator's presence and attempt to flee before the predator gets close. The chase ends either when the predator successfully catches up and tackles the prey, or when the predator abandons the attempt after the prey outruns it and escapes.
One particular form of pursuit predation is persistence hunting, where the predator stalks the prey slowly but persistently to wear it down physically with fatigue or overheating; some animals are examples of both types of pursuit.
Strategy
There is still uncertainty as to whether predators behave with a general tactic or strategy while preying. However, among pursuit predators there are several common behaviors. Often, predators will scout potential prey, assessing prey quantity and density prior to engaging in a pursuit. Certain predators choose to pursue prey primarily in a group of conspecifics; these animals are known as pack hunters or group pursuers. Other species choose to hunt alone. These two behaviors are typically due to differences in hunting success, where some groups are very successful in groups and others are more successful alone. Pursuit predators may also choose to either exhaust their metabolic resources rapidly or pace themselves during a chase. This choice can be influenced by prey species, seasonal settings, or temporal settings. Predators that rapidly exhaust their metabolic resources during a chase tend to first stalk their prey, slowly approaching their prey to decrease chase distance and time. When the predator is at a closer distance, it finally gives chase. Pacing pursuit is more commonly seen in group pursuit, as individual animals do not need to exert as much energy to capture prey. However, this type of pursuit requires group coordination, which may have varying degrees of success. Since groups can engage in longer chases, they often focus on separating a weaker or slower prey item during pursuit. Morphologically speaking, while ambush predation requires stealth, pursuit predation requires speed; pursuit predators are proportionally long-limbed and equipped with cursorial adaptations. Current theories suggest that this proportionally long-limbed approach to body plan was an evolutionary countermeasure to prey adaptation.Group pursuers
Vertebrates
Group pursuers hunt with a collection of conspecifics. Group pursuit is usually seen in species of relatively high sociality; in vertebrates, individuals often seem to have defined roles in pursuit.Mammals
packs have been known to split into several smaller groups while in pursuit; one group initiates the chase, while the other travels ahead of the prey's escape path. The group of chase initiators coordinate their chase to lead the prey towards the location of the second group, where the prey's escape path will be effectively cut off.Bottlenose dolphins have been shown exhibiting similar behaviors of pursuit role specialization. One group within the dolphin pod, known as the drivers, give chase to the fish - forcing the fish into a tight circle formation, while the other group of the pod, the barriers, approach the fish from the opposite direction. This two-pronged attack leaves the fish with only the option of jumping out of the water to escape the dolphins. However, the fish are completely vulnerable in the air; it is at this point when the dolphins leap out and catch the fish.
In lion pack hunting, each member of the hunting group is assigned a position, from left wing to right wing, in order to better obtain prey. Such specializations in roles within the group are thought to increase sophistication in technique; lion wing members are faster, and will drive prey toward the center where the larger, stronger, killing members of the pride will take down the prey. Many observations of group pursuers note an optimal hunting size in which certain currencies are maximized with respect to costs. Groups size is often dependent on aspects of the environment: number of prey, prey density, number of competitors, seasonal changes, etc.
Birds
While birds are generally believed to be individual hunters, there are a few examples of birds that cooperate during pursuits. Harris's hawks have two cooperative strategies for hunting: Surrounding and cover penetration, and long chase relay attack.The first strategy involves a group of hawks surrounding prey hidden under some form of cover, while another hawk attempts to penetrate the prey's cover. The penetration attempt flushes the prey out from its cover where it is swiftly killed by one of the surrounding hawks.
The second strategy is less commonly used: It involves a "relay attack" in which a group of hawks, led by a "lead" hawk, engage in a long chase for prey. The "lead" hawk will dive in order to kill the prey. If the dive is unsuccessful, the role of the "lead" shifts to another hawk who will then dive in another attempt to kill the prey. During one observed relay attack, 20 dives and hence 20 lead switches were exhibited.
Invertebrates
As in vertebrates, there are many species of invertebrates which actively pursue prey in groups and exhibit task specialization, but while the vertebrates change their behavior based on their role in hunting, invertebrate task delegation is usually based on actual morphological differences. The vast majority of eusocial insects have castes within a population which tend to differ in size and have specialized structures for different tasks. This differentiation is taken to the extreme in the groups isoptera and hymenoptera, or termites and ants, bees, and wasps respectively.Termite-hunting ants of the genus Pachycondyla, also known as Matabele ants, form raiding parties consisting of ants of different castes, such as soldier ants and worker ants. Soldier ants are much larger than worker ants, with more powerful mandibles and more robust exoskeletons, and so they make up the front lines of raiding parties and are responsible for killing prey. Workers usually butcher and carry off the killed prey, while supporting the soldiers. The raiding parties are highly mobile and move aggressively into the colonies of termites, often breaking through their outer defenses and entering their mounds. The ants do not completely empty the mound of termites, instead they only take a few, allowing the termites to recover their numbers so that the ants have a steady stream of prey.
Asian giant hornets, Vespa mandarinia, form similar raiding parties to hunt their prey, which usually consists of honeybees. The giant hornets group together and as a team can decimate an entire honeybee colony, especially those of non-native European honeybees. Alone, the hornets are subject to attack by the smaller bees, who swarm the hornet and vibrate their abdomens to generate heat, collectively cooking the hornet until it dies. By hunting in groups, the hornets avoid this problem.
Individual pursuers
Vertebrates
Mammals
While most big cat species are either solitary ambush predators or pack hunters, cheetahs are primarily solitary pursuit predators. Widely known as the fastest terrestrial animal with running speeds reaching, cheetahs take advantage of their speed during chases. However, their speed and acceleration also have disadvantages, as both rely on anaerobic metabolism and can only be sustained for short periods of time. Studies show that cheetahs can maintain maximum speed for up to a distance of approximately, which is only about 20 seconds of sprinting, before fatigue and overheating set in. Due to these limitations, cheetahs are often observed quietly walking towards the prey to shorten the distance before running at moderate speeds during chases.There are claims that the key to cheetahs' pursuit being successful may not be just burst of sheer speed. Cheetahs are extremely agile, able to change directions in very short amounts of time while running at very high speeds. This maneuverability can make up for unsustainable high-speed pursuits, as it allows a cheetah to quickly close the distance without having to decelerate when the prey suddenly changes direction. Due to being lightly built, cheetahs will try to foot sweep and unbalance the prey, instead of grasping and tackling. Only after the prey has fallen over and thus momentarily stopped running, the cheetah will pounce and try to subdue it with a throat bite.