Predator that sits and waits for prey to come to it
Ambush predators or sit-and-wait predators are
carnivorous animals that
capture their
prey via
stealth,
luring or by (typically
instinctive)
strategies utilizing an element of surprise. Unlike
pursuit predators, who chase to capture prey using sheer
speed or
endurance, ambush predators avoid
fatigue by staying in concealment, waiting patiently for the prey to get near, before launching a sudden overwhelming attack that quickly incapacitates and captures the prey.
The ambush is often opportunistic, and may be set by hiding in a
burrow, by
camouflage, by
aggressive mimicry, or by the use of a trap (e.g. a
web). The predator then uses a combination of
senses to
detect and assess the prey, and to time the strike. Nocturnal ambush predators such as
cats and
snakes have vertical slit
pupils helping them to judge the distance to prey in dim light. Different ambush predators use a variety of means to capture their prey, from the long sticky tongues of
chameleons to the expanding mouths of
frogfishes.
Ambush predators usually remain motionless (sometimes hidden) and wait for prey to come within ambush distance before pouncing. Ambush predators are often
camouflaged, and may be solitary.
Pursuit predation becomes a better strategy than ambush predation when the predator is faster than the prey.[2] Ambush predators use many intermediate strategies. For example, when a pursuit predator is faster than its prey over a short distance, but not in a long chase, then either stalking or ambush becomes necessary as part of the strategy.[2]
Bringing the prey within range
Concealment
Ambush often relies on concealment, whether by staying out of sight or by means of camouflage.
Trapdoor spiders excavate a burrow and seal the entrance with a web trapdoor hinged on one side with silk. The best-known is the thick, bevelled "cork" type, which neatly fits the burrow's opening. The other is the "wafer" type; it is a basic sheet of silk and earth. The door's upper side is often effectively camouflaged with local materials such as pebbles and sticks. The spider spins silk fishing lines, or trip wires, that radiate out of the burrow entrance. When the spider is using the trap to capture prey, its
chelicerae (protruding mouthparts) hold the door shut on the end furthest from the hinge. Prey make the silk vibrate, and alert the spider to open the door and ambush the prey.[7][8]
Many ambush predators make use of
camouflage so that their prey can come within striking range without detecting their presence. Among insects, coloration in
ambush bugs closely matches the flower heads where they wait for prey.[9] Among fishes, the
warteye stargazer buries itself nearly completely in the sand and waits for prey.[10] The
devil scorpionfish typically lies partially buried on the sea floor or on a coral head during the day, covering itself with sand and other debris to further camouflage itself.[11][12][13][14] The
tasselled wobbegong is a shark whose adaptations as an ambush predator include a strongly flattened and camouflaged body with a
fringe that breaks up its outline.[15] Among amphibians, the
Pipa pipa's brown coloration blends in with the murky waters of the Amazon Rainforest which allows for this species to lie in wait and ambush its prey.[16]
Many ambush predators actively attract their prey towards them before ambushing them. This strategy is called
aggressive mimicry, using the false promise of nourishment to lure prey. The
alligator snapping turtle is a well-camouflaged ambush predator. Its tongue bears a conspicuous pink extension that resembles a
worm and can be wriggled around;[17] fish that try to eat the "worm" are themselves eaten by the turtle. Similarly, some reptiles such as Elaphe rat snakes employ
caudal luring (tail luring) to entice small vertebrates into striking range.[18]
The
zone-tailed hawk, which resembles the
turkey vulture, flies among flocks of turkey vultures, then suddenly breaks from the formation and ambushes one of them as its prey.[19][20] There is however some controversy about whether this is a true case of
wolf in sheep's clothing mimicry.[21]
Flower mantises are aggressive mimics, resembling
flowers convincingly enough to attract prey that come to collect pollen and nectar. The
orchid mantis actually attracts its prey,
pollinator insects, more effectively than flowers do.[22][23][24][25]Crab spiders, similarly, are coloured like the flowers they habitually rest on, but again, they can lure their prey even away from flowers.[26]
Some ambush predators build traps to help capture their prey. Lacewings are a flying insect in the order
Neuroptera. In some species, their larval form, known as the
antlion, is an ambush predator. Eggs are laid in the earth, often in caves or under a rocky ledge. The juvenile creates a small, crater shaped trap. The antlion hides under a light cover of sand or earth. When an ant, beetle or other prey slides into the trap, the antlion grabs the prey with its powerful jaws.[27][28]
Some but not all
web-spinningspiders are sit-and-wait ambush predators. The sheetweb spiders (
Linyphiidae) tend to stay with their webs for long periods and so resemble sit-and-wait predators, whereas the orb-weaving spiders (such as the
Araneidae) tend to move frequently from one patch to another (and thus resemble active foragers).[29]
Detection and assessment
Ambush predators must time their strike carefully. They need to detect the prey, assess it as worth attacking, and strike when it is in exactly the right place. They have evolved a variety of adaptations that facilitate this assessment. For example,
pit vipers prey on small birds, choosing targets of the right size for their mouth gape: larger snakes choose larger prey. They prefer to strike prey that is both warm and moving;[31] their pit organs between the eye and the nostril contain
infrared (heat) receptors, enabling them to find and perhaps judge the size of their small, warm-blooded prey.[32]
The deep-sea tripodfish Bathypterois grallator uses tactile and mechanosensory cues to identify food in its low-light environment.[33] The fish faces into the current, waiting for prey to drift by.[34][35][36]
Several species of
Felidae (cats) and snakes have vertically elongated (slit) pupils, advantageous for
nocturnal ambush predators as it helps them to estimate the distance to prey in dim light; diurnal and pursuit predators in contrast have round pupils.[30]
Capturing the prey
Mantis shrimp captures its prey rapidly with its mantis-like front legs.
Frogfish traps its prey by suddenly opening its jaws and sucking the prey in.
Ambush predators often have adaptations for seizing their prey rapidly and securely. The capturing movement has to be rapid to trap the prey, given that the attack is not modifiable once launched.[6][37]Zebra mantis shrimp capture agile prey such as fish primarily at night while hidden in burrows, striking very hard and fast, with a mean peak speed 2.30 m/s (5.1 mph) and mean duration of 24.98 ms.[37]
Chameleons (family Chamaeleonidae) are highly adapted as ambush predators.[38] They can change colour to match their surroundings and often climb through trees with a swaying motion, probably to mimic the movement of the leaves and branches they are surrounded by.[38] All chameleons are primarily
insectivores and feed by
ballistically projecting their
tongues, often twice the length of their bodies, to capture prey.[39][40] The tongue is projected in as little as 0.07 seconds,[41][42] and is launched at an acceleration of over 41
g.[42] The
power with which the tongue is launched, over 3000 W·kg−1, is more than muscle can produce, indicating that energy is stored in an elastic tissue for sudden release.[41]
All fishes face a basic problem when trying to swallow prey: opening their mouth may pull food in, but closing it will push the food out again.
Frogfishes capture their prey by suddenly opening their jaws, with a mechanism which enlarges the volume of the mouth cavity up to 12-fold and pulls the prey (
crustaceans,
molluscs and other whole fishes) into the mouth along with water; the jaws close without reducing the volume of the mouth cavity. The attack can be as fast as 6 milliseconds.[43]
^Kramer, Donald L. (2001).
"Foraging behavior"(PDF). In Fox, C. W.; Roff, D. A.; Fairbairn, D. J. (eds.). Evolutionary Ecology: Concepts and Case Studies. Oxford University Press. pp. 232–238.
ISBN9780198030133. Archived from
the original(PDF) on 12 July 2018. Retrieved 20 September 2018.
^Spindel, E. L.; Dobie, J. L.; Buxton, D. F. (2005). "Functional mechanisms and histologic composition of the lingual appendage in the alligator snapping turtle, Macroclemys temmincki (Troost) (Testudines: Chelydridae)". Journal of Morphology. 194 (3): 287–301.
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10.1002/jmor.1051940308.
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^Mullin, S.J. (1999). "Caudal distraction by rat snakes (Colubridae, Elaphe): A novel behaviour used when capturing mammalian prey". Great Basin Naturalist. 59: 361–367.
^Smith, William John (2009).
The Behavior of Communicating: an ethological approach. Harvard University Press. p. 381.
ISBN978-0-674-04379-4. Others rely on the technique adopted by a wolf in sheep's clothing—they mimic a harmless species. ... Other predators even mimic their prey's prey: angler fish (Lophiiformes) and alligator snapping turtles Macroclemys temmincki can wriggle fleshy outgrowths of their fins or tongues and attract small predatory fish close to their mouths.
^Annandale, Nelson (1900). "Observations on the habits and natural surroundings of insects made during the 'Skeat Expedition' to the Malay Peninsula, 1899–1900". Proceedings of the Zoological Society of London. 69: 862–865.
^Levine, Timothy R. (2014).
Encyclopedia of Deception. Sage Publications. p. 675.
ISBN978-1-4833-8898-4. In aggressive mimicry, the predator is 'a wolf in sheep's clothing'. Mimicry is used to appear harmless or even attractive to lure its prey.
^Janetos, Anthony C. (1982). "Foraging tactics of two guilds of web-spinning spiders". Behavioral Ecology and Sociobiology. 10 (1): 19–27.
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abTolley, Krystal A.; Herrel, Anthony (2013).
The Biology of Chameleons.
University of California Press. p. 128.
ISBN978-0-520-95738-1. Chameleons may also employ a form of movement-based camouflage, ... [they] often rhythmically rock backward and forward as they walk ... [perhaps] imitating a swaying leaf ... moving in the breeze ... The behavior is widespread in highly cryptic, generally slow-moving, ambush predators, notably chameleons and some snakes and mantids
^Anderson, C. V.; Sheridan, T.; Deban, S. M. (2012). "Scaling of the ballistic tongue apparatus in chameleons". Journal of Morphology. 273 (11): 1214–1226.
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^Browne-Cooper, Robert; Brian Bush; Brad Maryan; David Robinson (2007). Reptiles and Frogs in the Bush: Southwestern Australia. University of Western Australia Press. pp. 145, 146.
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^Ryan, P. G. (2007). "Diving in shallow water: the foraging ecology of darters (Aves: Anhingidae)". Journal of Avian Biology. 38 (4): 507–514.
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10.1111/j.2007.0908-8857.04070.x.