Prey snapping and visual distance estimation in Texas horned lizards, <i>Phrynosoma cornutum</i>

Ott, Matthias; Ostheim, Joachim; Sherbrooke, Wade C.

doi:10.1242/jeb.01153

Cited by 13 publications

(4 citation statements)

References 18 publications

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“…On the contrary, by orienting directly toward a predator, a prey lacking or having limited binocular vision may lose sight of it or encounter focusing problems. However, the ability of many lizards to catch prey located directly in front of them (e.g., Ott et al 2004) emphasizes the need for studies of lizard visual fields.…”

Section: Discussionmentioning

confidence: 99%

Monitoring by prey that does not reveal awareness by turning toward approaching predators

Cooper

Sherbrooke

2015

Behav Ecol Sociobiol

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Prey monitor predator movements to assess risk, as required to make escape decisions and avoid being captured unaware. For prey that exhibit behavioral signs that they have detected predators, alert distance is the predator-prey distance when the prey performs the behavior and then continuously monitors the predator's approach. Many other prey do not usually give any indication of having detected a predator prior to fleeing. This is especially likely in prey having laterally placed eyes that are approached from one side, as in typical studies of lizards. We conducted field trials to detect overt signs of monitoring by zebra-tailed lizards, Callisaurus draconoides, which usually exhibit no signs of monitoring. When a researcher walked in an arc starting at some distance from a lizard's side and continuing until he was directly in front of or behind it, the lizard cocked its head and/or reoriented its body or fled and then reoriented. These behaviors allowed lizards to keep the researcher in view as he passed out of a monocular visual field. The findings demonstrate that monitoring occurs in these lizards, suggest that monitoring is so important that lizards risk being detected by moving, and suggest a possible method for studying effects of alert distance in prey that do not perform alerting behaviors when approached in full view. Alerting responses have been observed infrequently in lizards because researchers are in one of the wide lateral visual fields when they start to approach.Unless the predator moves out of view, prey with limited or no binocular vision have no need for postural adjustment to focus on the predator.

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Section: Discussionmentioning

confidence: 99%

Monitoring by prey that does not reveal awareness by turning toward approaching predators

Cooper

Sherbrooke

2015

Behav Ecol Sociobiol

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“…The use of a prehensile tongue for capturing prey is a typical feature of the three main iguanian lizard families Iguanidae, Agamidae, and Chamaeleonidae (phylum: Chordata, class: Reptilia, order Squamata) [ 111 ]. Although all iguanian lizards use their tongue to capture prey, there are differences in the mechanism and the maximum protrusion and projection distances of the tongue.…”

Section: Animalsmentioning

confidence: 99%

Shooting Mechanisms in Nature: A Systematic Review

et al. 2016

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BackgroundIn nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these mechanisms fulfill.MethodsWe systematically searched the literature using Scopus and Web of Knowledge to retrieve articles about solid projectiles that either are produced in the body of the organism or belong to the body and undergo a ballistic phase. The shooting mechanisms were categorized based on the energy management prior to and during shooting.ResultsShooting mechanisms were identified with projectile masses ranging from 1·10−9 mg in spores of the fungal phyla Ascomycota and Zygomycota to approximately 10,300 mg for the ballistic tongue of the toad Bufo alvarius. The energy for shooting is generated through osmosis in fungi, plants, and animals or muscle contraction in animals. Osmosis can be induced by water condensation on the system (in fungi), or water absorption in the system (reaching critical pressures up to 15.4 atmospheres; observed in fungi, plants, and animals), or water evaporation from the system (reaching up to −197 atmospheres; observed in plants and fungi). The generated energy is stored as elastic (potential) energy in cell walls in fungi and plants and in elastic structures in animals, with two exceptions: (1) in the momentum catapult of Basidiomycota the energy is stored in a stalk (hilum) by compression of the spore and droplets and (2) in Sphagnum energy is mainly stored in compressed air. Finally, the stored energy is transformed into kinetic energy of the projectile using a catapult mechanism delivering up to 4,137 J/kg in the osmotic shooting mechanism in cnidarians and 1,269 J/kg in the muscle-powered appendage strike of the mantis shrimp Odontodactylus scyllarus. The launch accelerations range from 6.6g in the frog Rana pipiens to 5,413,000g in cnidarians, the launch velocities from 0.1 m/s in the fungal phylum Basidiomycota to 237 m/s in the mulberry Morus alba, and the launch distances from a few thousands of a millimeter in Basidiomycota to 60 m in the rainforest tree Tetraberlinia moreliana. The mass-specific power outputs range from 0.28 W/kg in the water evaporation mechanism in Basidiomycota to 1.97·109 W/kg in cnidarians using water absorption as energy source.Discussion and conclusionsThe magnitude of accelerations involved in shooting is generally scale-dependent with the smaller the systems, discharging the microscale projectiles, generating the highest accelerations. The mass-specific power output is also scale dependent, with smaller mechanisms being able to release the energy for shooting faster than larger mechanisms, whereas the mass-specific work delivered by the shooting mechanism is mostly independent of the scale of the shooting mechanism. Higher mass-specific work-values are observed in osmosis-powered shooting mechanisms (≤ 4,137 J/kg) when compared to muscle-powered m...

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“…To capture prey successfully, information about prey size (Schwenk and Throckmorton, '89; Anderson and Nishikawa, '96; Ferry‐Graham, '98), shape (Valdez and Nishikawa, '97), location (Monroy and Nishikawa, 2009), and velocity are particularly important. Many vertebrates, including parrotfish (Rice and Westneat, 2005), salamanders (Deban, '97), frogs (Anderson and Nishikawa, '96), and lizards (Ott et al, 2004), use visual cues to modulate prey‐capture behavior for prey that differ in size, shape, or location. Tactile (Comer and Grobstein, '81) and proprioceptive (Anderson and Nishikawa, '93, '96; Schaerlaeken et al, 2007) cues may also be used to modulate prey‐capture behavior.…”

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confidence: 99%

Prey capture in frogs: alternative strategies, biomechanical trade‐offs, and hierarchical decision making

Monroy

Nishikawa

2011

J. Exp. Zool.

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Frogs exhibit flexible repertoires of prey-capture behavior, which depend primarily on visual analysis of prey attributes. We review three examples of how visual cues are used to modulate prey-capture strategies. (1) Dyscophus guineti modulates tongue aiming in response to prey location. These frogs turn only their heads to apprehend prey located at azimuths o401. At azimuths 4401, the frogs switch from this strategy to one in which both head and tongue are aimed toward prey. (2) Rana pipiens modulates its feeding behavior in response to prey size, using tongue prehension for capturing small prey but switching to jaw prehension to capture large prey. (3) In Cyclorana novaehollandiae, visual processing of prey attributes involves hierarchical decision making. These frogs first assess prey size. For large prey, they ignore velocity but not shape. For small prey, they ignore shape but not velocity. Alternative prey-capture strategies are associated with biomechanical trade-offs that result from the interaction between the feeding apparatus and varying attributes of prey. Alternative strategies likely exist because biomechanical constraints prevent any one strategy from being effective over a range of prey attributes. Taken together, these studies emphasize the requirement that predators must somehow tune prey-capture kinematics simultaneously to multiple attributes of prey. In frogs, the choice among alternative prey-capture strategies involves a hierarchical decision-making process. Hierarchical decision making is expected to be widespread among animals. However, no previous studies were found except for humans, who frequently use this type of approach to make complex decisions.

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Prey snapping and visual distance estimation in Texas horned lizards, Phrynosoma cornutum

Cited by 13 publications

References 18 publications

Monitoring by prey that does not reveal awareness by turning toward approaching predators

Monitoring by prey that does not reveal awareness by turning toward approaching predators

Shooting Mechanisms in Nature: A Systematic Review

Prey capture in frogs: alternative strategies, biomechanical trade‐offs, and hierarchical decision making

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