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Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioral and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system. ...
The eyes of insects are sensitive to a natural phenomenon that man is blind to: the polarized light of the daytime sky. It is this capacity that underlies the remarkable navigational ability of many insect species.
There is one point in the sky that by itself leads to unambiguity in navigation: the position occupied by the sun. This point lacks polarized light. It is also the brightest point in the sky. When we followed our desert ants after adapting the tracking vehicle so that the entire sky was depolarized, the navigational ability of the ants became very erratic. This happened in spite of the fact that the position occupied by the sun still remained the brightest part of the depolarized sky. One might conclude that whatever the ant's internal representation of the sky may be, the sun may be predominantly recognized as the point of least polarization.
In bees that point has become particularly meaningful. Because bees have developed the abstract language of the dance as a means of telling one another about navigation angles, each individual worker bee must be able to make use of a reference point that is common to all its fellow workers. Moreover, such a common reference point must be uniquely recognizable within the overall pattern of sky polarization. Therefore the position of the sun-the point of zero polarization-is the only point bees could select for unambiguous communication. The importance of the sun as a cue in bee navigation may well have resulted from its lack of polarization rather than from its relative brightness ...
While a number of animal species have been demonstrated to use the stars as a source of directional information, the strategies that these animals use to convert this complex and variable pattern of dim-light points into a reliable ‘stellar orientation’ cue have been more difficult to ascertain. In this review, we assess the stars as a visual stimulus that conveys directional information, and compare the bodies of evidence available for the different stellar orientation strategies proposed to date. In this context, we also introduce new technologies that may aid in the study of stellar orientation, and suggest how field experiments may be used to characterize the mechanisms underlying stellar orientation. ...
During their autumn migration, wild-caught birds were presented with an autumn starry sky in the Longway Planetarium (Flint, Michigan) while constrained within funnels of blotting paper that monitored the direction of their hops when they attempted to take-off. Their hops were consistently oriented southwards, as when presented with a real starry sky [13]. This behavior persisted with the removal of successive constellations, and P. cyanea was only disoriented when all of the constellations within 35° of Polaris were blocked from view [14]. Birds attempting to migrate south in autumn, and those manipulated physiologically for early spring migration northwards, displayed season-appropriate orientation when presented with the same planetarium sky [15]. Various attempts to demonstrate stellar orientation in other migratory bird species [16–19] indicate that several other night-migrating species also use the centre of celestial rotation as their stellar orientation reference.
In a series of studies involving the harbour seal Phoca vitulina, it was established that seals can detect simulated and real bright stars [29] and that they can learn to orient within a floating planetarium [30].
It is often assumed that navigation implies the use, by animals, of landmarks indicating the location of the goal. However, many animals (including humans) are able to return to the starting point of a journey, or to other goal sites, by relying on self-motion cues only. This process is known as path integration, and it allows an agent to calculate a route without making use of landmarks
Path integration—first postulated by Darwin (1873) and described by Murphy (1873), in reply to Darwin, as the integration of inertial signals— appears to operate in a great number of diverse species with a fixed home base, both vertebrate and invertebrate, during the exploration of a new environment or in commuting between the home and familiar resource sites. It may also provide continuous information to the animal about where it is located on its internal representation of space (Gallistel, 1990), particularly in the intervals between visual fixes (e.g., in darkness). PI functions automatically and constantly, whenever the agent moves in continuous space. Thus, a central place forager may, for instance, interrupt its excursion to return home at any place and at any moment of its journey ...
With regard to the question of the means by which animals find their way home from a long distance, a striking account, in relation to man, will be found in the English translation of the Expedition to North Siberia, by Von Wrangell.[note 1] He there describes the wonderful manner in which the natives kept a true course towards a particular spot, whilst passing for a long distance through hummocky ice, with incessant changes of direction, and with no guide in the heavens or on the frozen sea. He states (but I quote only from memory of many years standing) that he, an experienced surveyor, and using a compass, failed to do that which these savages easily effected. Yet no one will suppose that they possessed any special sense which is quite absent in us. We must bear in mind that neither a compass, nor the north star, nor any other such sign, suffices to guide a man to a particular spot through an intricate country, or through hummocky ice, when many deviations from a straight course are inevitable, unless the deviations are allowed for, or a sort of "dead reckoning" is kept. All men are able to do this in a greater or less degree, and the natives of Siberia apparently to a wonderful extent, though probably in an unconscious manner. This is effected chiefly, no doubt, by eyesight, but partly, perhaps, by the sense of muscular movement, in the same manner as a man with his eyes blinded can proceed (and some men much better than others) for a short distance in a nearly straight line, or turn at right angles, or back again. The manner in which the sense of direction is sometimes suddenly disarranged in very old and feeble persons, and the feeling of strong distress which, as I know, has been experienced by persons when they have suddenly found out that they have been proceeding in a wholly unexpected and wrong direction, leads to the suspicion that some part of the brain is specialized for the function of direction. ...
Vikings have gone down in history as legendary navigators, sailing their long ships to places like Britain, Ireland, Greenland and even Newfoundland. Without magnetic compasses or tools like astrolabes, the Vikings likely relied on primitive solar compasses to navigate, which uses the position of the sun to determine north.
Although the Vikings are widely known to have been excellent mariners, exactly how they navigated the seas is not well understood. Since the northern Atlantic Ocean where they sailed has up to 24 hours of daylight in the summer, they could not have relied heavily on the stars, but likely took full advantage of the sun to navigate.
Compasses that used the angle and length of the sun's shadow to determine the position of the north were used throughout of human history in several forms, ranging from simple techniques used in ancient Greece and Rome to the caved half-discs of Viking sailors that could not only work during the day, but also very reliable (with just a few percent of error) determine the position of the north even up to 45 minutes after the sunset. ...
Although eleventh-century Vikings did not have magnetic compasses at their disposal, it is thought that they could determine their orientation at sea using sun-compasses. Sun-compasses use the position of the sun's shadow to tell which way north is, and look somewhat similar to sundials, which use the position of the sun's shadow to tell the time of day. But the famous Viking-era wooden fragment that inspired the idea that Vikings used sun-compasses contains some lines that don't quite match scientists' interpretations. In a new study, a team of researchers has proposed that these flaws hint at the possibility that the instrument served a more sophisticated purpose than determining orientation, which was determining latitude. ...
Our results show that the sky-polarimetric navigation is surprisingly successful on both days of the spring equinox and summer solstice even under cloudy conditions if the navigator determined the north direction periodically at least once in every 3 h, independently of the type of sunstone used for the analysis of sky polarization. This explains why the Vikings could rule the Atlantic Ocean for 300 years and could reach North America without a magnetic compass. Our findings suggest that it is not only the navigation periodicity in itself that is important for higher navigation success rates, but also the distribution of times when the navigation procedure carried out is as symmetrical as possible with respect to the time point of real noon.
If the navigation periodicity Δt is 1, 2 or 3 h, then the navigation success s is between 92.2 and 100% for all three sunstones and at both spring equinox and summer solstice. ...
Aboriginal Australians are the oldest continuing culture on Earth, and have been living in Australia for over 50,000 years. They may be the world’s oldest astronomers, as their culture has retained much astronomical knowledge, passed down through stories, song and art. They have a sophisticated knowledge of the night sky, including the movement of the Moon and its effect on the tides, the mechanism of solar eclipses, and the location and movement of planets and stars down to 5th magnitude.
traditional Pacific navigators (and Western navigators before the time of Cook) had no way in which they could precisely fix their position on the open ocean as modern, instrument navigators can. Instead, Pacific navigators were accomplished in the art of dead reckoning, a world-wide practice whereby a navigator deduces his position from estimates of course and speed “made good” after allowing for the estimated effects of leeway (sideways drift of the vessel caused by the wind) and current.
Pacific Island navigators, however, had to develop a system which allowed them to overcome a very special handicap: without written language, their practice of navigation was entirely mental, with reckoning of position being carried forward through the voyage in a navigator's memory. The continuous level of concentration required is much higher than in modern navigation, with its written logs, and plots on charts, regularly updated.
Exactly how traditional Polynesian navigators used dead reckoning is not known. For the Caroline Islands there are abundant data on a dead reckoning system which involves mentally dividing a voyage into segments marked by the change in the bearing of an etak or “reference” island, as judged by its envisioned movement from one star compass point to another ...
There are eight distinct swells. Each one is connected to a specific position of a star on the star compass. But swells tell more than what course you’re on. If you can read their shapes, you can know the strength and direction of the current running beneath them. If you don’t know what the current’s doing, you can steer a perfect course and still become lost. ...
originally posted by: blend57
Path integration:
It is often assumed that navigation implies the use, by animals, of landmarks indicating the location of the goal. However, many animals (including humans) are able to return to the starting point of a journey, or to other goal sites, by relying on self-motion cues only. This process is known as path integration, and it allows an agent to calculate a route without making use of landmarks
That's the clearest/simplest definition I could find. Animals use this to navigate short distances mostly. A simple example would be knowing where "home" is and traveling 200 paces North, then 200 paces to the right, then another 200 paces to the right, then once more. Doing that will get you back to your starting point. It can be as simple or complex as you need it to be honestly. But the point is to keep track of the distance you cover rather than the land marks or direction.
originally posted by: InspectorGadget13
Very cool! Commenting so i can come back and read the whole thread later.