The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

Rodda, Gordon H.

doi:10.1007/bf01350218

Cited by 69 publications

(40 citation statements)

References 26 publications

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“…Evidence for a magnetite-based ÔmapÕ in other animals is not yet available, although several authors (e.g. Quinn 1984;Rodda 1984;Phillips 1986;Lohmann and Lohmann 1994;Phillips and Borland 1994) have suggested that other vertebrates may derive navigational information from the magnetic field. If the ÔmapÕ of other vertebrates is also based on magnetic information, its underlying receptor is most probably magnetite-based.…”

Section: Discussionmentioning

confidence: 99%

Effect of Wavelength of Light and Pulse Magnetisation on Different Magnetoreception Systems in a Migratory Bird

Munro¹,

Munro²,

Phillips³

et al. 1997

Aust. J. Zool.

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Two hypotheses on magnetoreception in animals are currently discussed. The first hypothesis is based on light-dependent processes associated with the visual system, while the second hypothesis suggests that magnetoreception is based on biogenic magnetite. Both mechanisms are supported by experimental evidence, but whether the information they provide involves the magnetic compass or the ‘map’ is still open. In order to identify the relevance of light-dependent or magnetite-transduced processes in magnetoreception, juvenile migratory birds were tested for their orientation behaviour in the natural geomagnetic field as the only directional cue available to them. The test birds were juvenile Tasmanian silvereyes (Zosterops l. lateralis), which were caught on their native island soon after fledging, before they had an opportunity to establish a navigational ‘map’. (1) Under ‘white’ (full spectrum) and green light (571 nm), they were well oriented in their appropriate migratory direction, while they were disoriented under red light (633 nm). This coincides with previous findings on adult silvereyes and suggests that light-dependent processes are involved in an orientation mechanism used by both juvenile and adult migrants, namely the magnetic compass. (2) A short, high-intensity magnetic pulse, a treatment designed to alter the magnetisation of magnetite, did not affect the young birds´ orientation. They continued to select their seasonally appropriate migratory direction. In contrast, adult silvereyes from the same population had responded in a previous study with a 90° clockwise deflection from their normal migratory course. These results suggest that (a) magnetite is involved in an orientation mechanism used exclusively by adult migrants; and (b) a magnetite-based receptor is associated with the navigational ‘map’, which provides information on geographic position.

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Section: Discussionmentioning

confidence: 99%

Effect of Wavelength of Light and Pulse Magnetisation on Different Magnetoreception Systems in a Migratory Bird

Munro¹,

Munro²,

Phillips³

et al. 1997

Aust. J. Zool.

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“…This led to the hypothesis that ISOs are the first identified vertebrate integumentary osmoreceptors (Jackson and Brooks, 2007). Other investigators have proposed that ISOs could function as magnetoreceptors (Rodda, 1984) or electroreceptors (Bullock, 1999).…”

Section: Behaviormentioning

confidence: 99%

“…They have been hypothesized to play a role in secreting cleansing and waterproofing oils (Grigg and Gans, 1993), enabling osmoreception (Jackson and Brooks, 2007;Jackson et al, 1996), mediating mechanotransduction (Necker, 1974) and facilitating courtship behavior (Brazaitis and Watanabe, 2011). Other suggestions include possibly acting as electroreceptors, as a consequence of the aquatic habitat of crocodilians (Bullock, 1999), or acting as magnetoreceptors, an ability noted in alligators (Rodda, 1984). More recently, Soares (Soares, 2002) discovered that these structures in juvenile Alligator mississippiensis mediate an orienting response to the center of a water surface disturbance.…”

Section: Introductionmentioning

confidence: 99%

Structure, innervation and response properties of integumentary sensory organs in crocodilians

Leitch

Catania

2012

Journal of Experimental Biology

126

142

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2) receptive fields, often from a single ISO, were recorded from the premaxilla, the rostral dentary, the gingivae and the distal digits. These responded to a median threshold of 0.08mN. The less densely innervated caudal margins of the jaws had larger receptive fields (>100mm 2 ) and higher thresholds (13.725mN). Rapidly adapting, slowly adapting type I and slowly adapting type II responses were identified based on neuronal responses. Several rapidly adapting units responded maximally to vibrations at 20-35Hz, consistent with reports of the ISOsʼ role in detecting prey-generated water surface ripples. Despite crocodiliansʼ armored bodies, the ISOs imparted a mechanical sensitivity exceeding that of primate fingertips. We conclude that crocodilian ISOs have diverse functions, including detection of water movements, indicating when to bite based on direct contact of pursued prey, and fine tactile discrimination of items held in the jaws. Supplementary material available online at

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“…5 Geomagnetic cues have been shown to be used by several species of sea turtles 40,41 and alligators. 42 The work in sea turtles is notable because it has been shown that hatchlings first find the ocean by reflected light from the ocean's surface and then swim seaward by using the wave orientation. Orientation by these cues is then transferred to a magnetic compass system.…”

Section: Orientation Cuesmentioning

confidence: 99%

From slither to hither: Orientation and spatial learning in snakes

Holtzman

1998

Integr. Biol.

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The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

Cited by 69 publications

References 26 publications

Effect of Wavelength of Light and Pulse Magnetisation on Different Magnetoreception Systems in a Migratory Bird

Effect of Wavelength of Light and Pulse Magnetisation on Different Magnetoreception Systems in a Migratory Bird

Structure, innervation and response properties of integumentary sensory organs in crocodilians

From slither to hither: Orientation and spatial learning in snakes

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