Orientation in a desert lizard (Uma notata): time-compensated compass movement and polarotaxis

Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye

“…Because in all of these experiments (including the present one) lizards with fully covered parietal eyes were disoriented in spite of the fact that their lateral eyes were unobstructed, the data so far available strongly suggest that contribution of the lateral eyes to sun-compass orientation of lizards is apparently irrelevant. Interestingly, several authors proposed that the lizard parietal eye could mediate a sky polarization compass sense, which may provide an advantage over a sun azimuth compass, because it remains functional even when the sun's position is obscured by vegetation and clouds (Adler and Phillips, 1985;Ellis-Quinn and Simon, 1991;Freake, 1999;Freake, 2001). This view is supported so far by anatomical data suggesting that the photoreceptors in the parietal eye are arranged in a pattern that would theoretically allow for analysis of the e-vector of linearly polarized light (Hamasaki and Eder, 1977;Freake, 1999).…”

“…Some investigations showed that lizards can use a time-compensated sun compass: orientation of 6 h fast or slow clock-shifted spiny lizards (Sceloporus jarrovi) deviates in the expected directions either in homing experiments in the field (Ellis- Quinn and Simon, 1991) or in orientation tests performed in an outdoor arena after directional training [fringe-toed lizard Uma notata (Adler and Phillips 1985)]. Homing experiments suggested that sleepy lizards (Tiliqua rugosa) use celestial cues to determine the compass bearing of the outward journey and reverse this bearing to orient in the homeward direction [course reversal (Freake, 2001)].…”

“…Further field work in S. jarrovi and T. rugosa examined whether the parietal eye of lizards is involved in homing orientation: lizards of both species orientated at random when the parietal eye was entirely covered with a patch whereas control individuals fitted with a sham parietal eye patch were homeward orientated (Ellis- Quinn and Simon, 1991;Freake, 2001). Interestingly, the lizard parietal eye was proposed to mediate a sky polarization compass sense but no experiments were carried out so far to directly test that hypothesis (Adler and Phillips, 1985;Ellis-Quinn and Simon, 1991;Freake, 1999;Freake, 2001).…”

Behavioural and physiological mechanisms of polarized light sensitivity in birds

“…[4,5]), reptiles (e.g. [6,7]) and birds (this review), apart from mammals. However, while PL sensitivity is relatively well studied in a large number of invertebrates and some fish species (for summary see [1]), the behavioural and physiological mechanism of PL sensitivity in most other vertebrate classes, including birds, remains one of the big mysteries in sensory biology.…”

“…It enables them to use the sun compass also on partly overcast days, when the Sun itself is obscured by clouds, but parts of the blue, partially polarized sky still visible (e.g. [6,9,10]; reviewed in [1]). …”