|
||||||||||
|
||||||||||
|
||||||||||
|
||||||||||
hey hear calls between transients. Prey are also more vigilant if they smell predatopotted each other, the prey can signal to the predator to decrease the likelihood of an attack. These honest signals may benefit both the prey and predator, because they save the effort of a fruitless chase.[110] Signals that appear to deter attacks include stotting, for example by Thomson's gazellsh-up displays by lizards;[110] and good singing by skylarks after a pursuit begins.[110] Simply indicating that the predator has been spotted, as a hare does l and attack seems imminent, the prey still has several options. One is to flee, whether by running, jumping, climbing, burrowing or swimming.[122] The prey can gain some time by startling the predator. Many butterflies and moths have eyespots, wing markings that resemble eyes.[123] When a predator disturbs the insect, it reveals its hind wings in a in a ny of their adaptations seem designed to counter each other. For example, bats have sophisticated echolocation systems to detect insects and other prey,n characterized as an evolutionary arms race, an example of the coevolution of two species.[129] In a gene centered view of evolution, the genes of predator and prey can be thought of as competing for the prey's body.[129] However, the "life-dinner" principle of Dawkins and Krebs predicts that this arms race is asymmetric: if a predator fails to catch its prey, it loses its dinner, while if it sue predator, may sometimes be snstantly alert for predators, warning of their presence winstance, longer legs have an increased risk of breaking,[1xtent of the asymmetry in natural selection depends in part on the heritability of the adaptive traits.[131] Also, if a predator loses enough dinners, it too will lose its life.[130][131] On the other hand, the fitness cost of a given lost dinner is unpredictable, as the predator may quickly find better prey. In addition, mostth loudies of prey to detect predators do have limits. Belding's ground squirrel cannot distinguish between harriers flying at different heights, although only the low-flying birds are a threat.[105] Wading bior predators. This makes it more difficult to feed and sleep. Groups can provide more eyes, making detection of a predator macks by predators. There are several mechanisms that produce this effect. One is dilution, where, in the simplest scenario, if a given predator attacks a group of prey, the chances of a given individual being the target is reduced in proportion to the size of the group. However, it is difficult to separate this effect from other group-related benefits such as increased vore likely and reducing the level of vigilance needed by individuals.[107] Many species, such as Eurasian jays, give alarm calls warning of the presence of a predator; these givrds sometimes take flight when there does not appear to be any predator present. Although such false alarms waste energy and lose feeding timstlings are particularly vulnerable to predation, so birds take measures to protect their nests.[98] Where birds locate their nests can have a large effect on the frequency of predation. It is lowest for those such as woodpeckers that excavate their own nests and progressively higher for those on the ground, in canopies and in shrubs.[103] To compensate, shrub nesters must have more broods and shorter nesting times. Birds also choose appropriate habitat
