Animal navigation and biological rhythms: the inertial theory by Antonio B. Nafarrate

Editor’s comments:
This paper is quite old but it does propose another navigation mechanism than the current obsession with magnetic orientation.  The magnetic field  has the terrible drawback of changing all the time and birds have migrating successfully before and after the Earth’s magnetic field flipped South for North.  Albatrosses fitted with head magnets (to see if this ruined their navigation) did not get lost.

Abstract
The Coriolis acceleration (or force when acting on a mass) can be used to define an inertial bicoordinate map over the surface of the Earth. These coordinates closely correspond to geographic latitude and longitude measured in units of time; in addition the Coriolis force can generate a clock frequency or time base to “calibrate” the biological rhythms.  The elementary detectors are intramolecular rotors or oscillators acting as inertially controlled ion gates forming part of “tunnel” proteins bridging cellular bilayer membranes.  The precessional monitors of these rotors generate the frequencies that encode the space-time coordinates. From an evolutionary standpoint the simplest and earliest application of this inertial model is in a non-statolithic gravity sensing system (detection of the local vertical), followed by sensing of the Earth rotation (timing information) and evolving later into the fully developed bicoordinate navigation system necessary in any animal species capable of migrating or homing.

Introduction
In spite of the large existing body of knowledge and the large numbers of investigators working in the study of animal navigation or biological rhythms science still has no answers to the fundamental questions on these subjects. Several of the models proposed for animal navigation involve the use of a “clock”, suggesting an interaction between navigation and rhythms; in this model both problems are shown to be essentially connected through the same physical mechanism.

The idea that animals use inertial navigation is not new; among the earlier proponents are Darwin (1), Ising (2), Yeagley (3) and Barlow (4). This model in addition to the concepts used in these earlier models brings a whole new focus to the way that organisms make use of bio-inertial sensors to gain spatio-temporal information.

The inertial theory
An inertial device such as the Foucault pendulum has a particular period of rotation of its plane of oscillation for each latitude; at either pole this period is equal  to the duration of the true sidereal day (23h 56min 4.0996s) and it becomes  infinite at the equator with opposite sense of rotation in the North from the South hemisphere; from these is clear that at least in theory it is possible to measure latitude using a Foucault pendulum, a chronometer and some sort of simple binary rule or cue to decide among North or South hemisphere.

The inertial device that measures longitude does not exist. Because of the geometry problem only changes of longitude can be measured from an arbitrary meridian with the use of a spinning top, a chronometer and again a binary rule or simple cue to decide whether the longitudinal changes are in the East or the West direction. It works as follows: a spinning top anywhere on the Earth, except at either pole, even under ideal conditions will always have some precession because of the contradictory tendencies of falling “asleep”(alignment of the rotational axis with the vertical or local direction of gravity) and the conservation of angular momentum that demands that the axis of rotation should continue pointing to the same direction in space in spite of the rotation of the Earth; as a result a given spinning top will precess with a certain frequency related to the velocity of the motion of the top as it is carried by a rotating Earth (tangential velocity), if in addition the top is transported East or West with some other velocity the precessional frequency will be shifted by the mechanical analog of the well-known Doppler effect of acoustic and optics.

It was shown that a spinning stationary top precesses with a certain frequency because of the Earth rotation, if this frequency is copied by a non-inertial oscillator (neuronal chemical in an organism) the frequency of this oscillator can be used to monitor changes in the inertial oscillator indicating longitudinal displacements; furthermore the frequency in the stationary case identical for both types of oscillators is a suitable “time base” or clock reference frequency useful to time other events of biological interest associated with the Earth rotation. To keep track of the longitudinal displacements only is needed a simple integration of the frequency shifts and it will be shown below that this can be achieved in a surprisingly easy manner.

The comparison of frequencies is usually done by the ”beat” or interference methods ;if an inertial oscillator and a non-inertial one are tuned to the same frequency in the stationary condition and then they are displaced eastwards or westwards at a certain velocity the mechanical Doppler frequency shifts towards lower or higher frequencies respectively experienced by the inertial oscillator will have it beat with the neuronal or chemical non-inertial oscillator, the maxima and minima of amplitude of the beat frequency will happen at nearly equidistant points along any parallel of latitude independent of the velocity of the displacement, counting the beats is equivalent to counting units of distance if simple mathematical linearity is assumed. It is easy to see that this process of velocity integration reduces itself to something similar to counting steps.

Magnetism
After a long history of contradictory reports there is now solid evidence that magnetic fields similar in strength and even weaker than the geomagnetic fields interact with living organisms, the emerging picture is showing two different types of detection one polar and the other axial (5). The polar form can be traced to the chains of magnetite crystal domains (or similar magnetic compounds) described by Blakemore (6), the axial form does not have an accepted explanation at this time, but in the context of the inertial model supplies the strongest evidence of the existency of spinning tops as gravitational-inertial sensor that because of their actual nature (intramolecular rotors or oscillators) are perturbed by magnetic fields.

The following interpretation of the experimental results of Lindauer and Martin (7) with honey bees constitutes a dramatic illustration of the previous statement. Lindauer and Martin measured with incredible patience and accuracy several millions of bee dances and found that the bees were making an error or “missweisung” (actually the bees were never wrong, the error was in the human expectations of what the bees were supposed to do), the human model for the dances predicted the proper result when the beehive was magnetically shielded or the geomagnetic field was compensated by using Helmholtz coils.                                              It will be shown that in the combined influence of the gravitational and geomagnetic field the bees dance as if using an electrically charged spinning top to detect the direction of the vertical and for this reason the “pure” mechanical precession is perturbed by the magnetic Larmor precession. Lindauer and Martin´s summary of results indicate the following:

1-    The magnetic field does not introduce any error when the dance vector direction is along it. The inertial theory claims that this happens because the electromagnetic component of the top is “asleep” along the magnetic field and the Larmor precession is zero and the mechanical precession (gravitational-inertial) shows itself “pure” without error in a full agreement with human expectations (the Karl von Frisch model)

  • The error is largest when the dance vector is perpendicular to the geomagnetic field.

Again the claim of the inertial theory is that the sum of two vectors (the mechanical angular velocities of precession) shows the largest misalignment with the direction of either component just about when the Wiltschko’s (8) model for the magnetic compass of European robins.

Experimental evidence
Over the years a wealth of information pointing to the inertial nature of the navigational system in animal has accumulated but the data that did not fit the “orthodox” school of thinking was easily swept under the rug, and this is in part the reason why Able (9) describes the study of this subject in chaos and turmoil, and indeed it is true because of the lack of comprehensive model to introduce order in a large and ever growing pile of data.

Besides the example already described of the axial form of magnetic detector, the strongest evidence for inertial navigation is the papers that show lunar influences in the orientation and timing of diurnal species (10-12). Within the framework of generally accepted physical science the Moon has only two types of influences over the Earth and its terrestrial inhabitants, one is the inertial-gravitational (mechanical forces; best example: the tides) and the other is electromagnetic, in turn the electromagnetic influence can be divided into optical (direct response to lunar light through the visual system; included here is most of the poetic-romantic influence) and electromagnetic (non-visual). While the electromagnetic lunar influences indeed exist and have been measured they are of an intensity and periodicity such that they add a very small modulation or contribution to solar influences of the same nature and for that reason it is unlikely that lunar rhythms in living organisms are driven or synchronized through electromagnetic cues, on the other hand the situation reverses for mechanical influences where the Moon dominates and the Sun is the lesser contributor. In summary when an organism shows lunar periodicities and visual cues can be ruled out, suspect mechanical effects, if a rhythm has solar frequency components check for electromagnetic effects.

An intriguing hint to the relation between gravity and timing comes from the chemical-hormonal fact that the hormone that mediates the gravitational response of plants, indole acetic acid and the hormone associated with circadian rhythmicity in the pineal gland of vertebrates, melatonin belong to the same chemical family of indoles with serotonin and tryptophan.

Conclusions
There is evidence that animal migration routes are genetically encoded, the just described method of inertial navigation that reduces latitude and longitude to time differences or steps counting lend itself for very simple encoding, the coordinates of a migration path are given by sets of three numbers (date, longitude and latitude) all in time units. Counting in some early cultures was made with the help of beads tied on stings, and today our civilization stores and manipulates information though stings of        data encoded in a variety of physical ways, hence it should not surprise anyone that genetic “stings” can be used as counters. When migrating species expand their range they add new path to their ancestral route as if adding or splicing a new section to their route specification gene.

One of the strongest and earliest opponents to the concept of inertial navigation is Matthews (13) others who follow mainly repeated Matthews’s mistake clearly seen in his book Bird Navigationwhen the Coriolis acceleration is discussed, Matthews’ asserts that the Coriolis acceleration can only provide one coordinate and not a bicoordinate grid necessary for complete map information; curiously enough this inertial model is very similar to Matthews “all solar model” and his concept of astronomical grids. Matthews’ solar model is a daylight version of celestial navigation and it has a profound connection with this form of inertial navigation though a path only recognized early this century by Einstein’s relativity; all the laws of physics have the same form when formulated with respect coordinate axis formed by the axis of telescopes pointing the stars or by the spinning axis of gyroscopes pointing to the same stars, and if this would have been known in the late 1800’s the Michelson and Morley experiment would then have been superfluous, because it would have been recognized that an optical (electromagnetic) experiment could not circumvent the limitations known from Newtonian mechanics that prevent  measuring absolute velocities.

It is to Matthews credit his belief in a simple navigational system and his clear statement that “time is longitude, longitude is time” (13), and this model adds that latitude is also time and both can be defined inertially.

This inertial form of navigation and timing makes use of very basic physical mechanisms available for living organisms at their most early evolutionary stages, and for this reason simple primitive species can amaze us with nearly incredible navigational performances.

Note: A more detailed expanded version of this paper with its additional impact in all areas of biology is under preparation; interested persons are encouraged to contact the author.

References

  • Darwin, C.R. Origin of certain instincts. Nature, 7, 417-418 (1873). Also Barrett,  H.(ed.). The collected paper of Charles Darwin. The University of Chicago Press. Chicago (1977).
  • Ising, G. Die physikalische  Moeglichkeit  eines tierischen  Orienterungssinnes auf Basis der Endrotation. Ark. Astr. Fys., 32,1-23 (1945).
  • Yeagley, H.L. A preliminary study of physical basis of bird navigation. J.Appl. Phys., 18, 1035-1063 (1947).
  • Barlow, J.S.Inertial navigation as a basis for animal navigation. J. Theor. Biol., 6, 76-117 (1964).
  • Phillips, J.B. Two magnetoreception pathways in a migratory salamander. Science, 233, 765-767 (1986).
  • Blakemore, R. Magnetotactic bacteria. Science, 190, 377-379 (1975).
  • Lindauer, M. and Martin, H. Die Schwereorienterung der Bienen unter dem Einfluss des Erdmagetfeldes. Z. vergel. Physiol., 60, 219-243 (1968).
  • Wiltschko, W. and Wiltschko, R. Magnetic compass of European robins. Science, 176, 62-64 (1972).
  • Able,K.P. Mechanisms of orientation, navigation and homing. In: Gauthreaux, Jr, S.A. (ed.).Animal migration, orientation and navigation, pp. 283-373. Academic Press, New York (1980).
  • Mewaldt, R. and Brown, I. Behavior of sparrows of the genus zonotrichia in orientation cages during the lunar cycle. Z. Tierpsychol.,25,668-700 (1968)
  • Keeton, W.T. and Larkin, T. An apparent lunar rhythm in the day-to-day variations in initial bearings of homing pigeons. In: Schmidt – Koenig, K. and Keeton, W.T. (eds.). Animal Migration, Navigation and Homing. Springer- Verlag, Berlin (1978).
  • Lohmann, K.J. and Willows, A.O.D. Lunar –Modulated geomagnetic orientation by a marine mollusk. Science, 235,331-334 (1987).

13-  Matthews, G.V.T. Bird Navigation, 2ndedn. Cambridge University Press, London ( 1968)

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Timing avian long-distance migration

Susanne Åkesson is one of the foremost academics working in the field of animal navigation.  Her recent paper: “Timing avian long-distance migration: from internal clock mechanisms to global flights” is impressive and important.

Please see attached the whole paper: Timing avian long-distance migration: from internal clock mechanisms to global flights.

One of the critical questions is how animals, here she especially covers birds, decide when to set out for their migrations.  Obviously getting your timing wrong and arriving in the wrong place in the wrong season is catastrophic.

She covers the short daily body cycle but also the yearly cycle of breeding, moulting and migration.

One of the issues has always been how these internal body clocks which tend to drift are recalibrated.  Åkesson covers the issue of how calibrations with daytime could work, as in the tropics, birds such as cuckoos,  wintering in the Congo must know when to return to Europe to breed.  Equally birds in the high arctic with long summers with no nights have to know when to leave to go south in the autumn.

Tracking time must interact with tracking distance (some type of odometer).  Migrating birds must know how far they have flown on their long journeys to know where they are in relationship to their target destination.

Equally careful synchronisation must take place (especially for seabirds) to make their journeys to their breeding grounds. They must arrive on time to find partners and bring up their offspring.

Richard Nissen
Editor

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Human Navigation some ideas October 2017

Humans, who are after all sophisticated animals have a very highly developed frontal cortex. This does our intellectual thinking. The right side is usually dominant. It also tends to be where humans view their world. Almost no humans feel and respond to the sub conscious.

We have the concept of conscious frontal cortex operation and the sub-conscious operation that for instance runs our bodies on automatic. The sub-conscious is the description of our ancient brain at the base of our brains sitting directly on top of the spine just like other animals. Our navigational compass consisting of the firing of head cells as we change direction is located in the hippocampus in the very heart of this part of the brain.

Please see Prof Kate Jeffery’s work on how navigation works in the brain which is posted under the “how animal navigate “section.

As our navigational systems exist within this ancient brain of the sub-conscious it explains why, often enough, you find that asking native (human) navigators how they do it does not work as they do not consciously know what they are doing.

Of course, another of our heroes Tristan Gooley talks about how to carry out conscious navigation (natural navigation) based on clues in the landscape, but this, for me, is the same as how children just learn their own language but adults need to learn languages another more formal way.

Jon Ward has explained that his natural navigation in Africa was based on a know range where he knew all the landmarks etc. He has suggested that natural navigation is probably impossible outside the adopted home range. I think that London taxi drivers would agree.

Richard Nissen
October 2017

 

 

 

 

 

 

 

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Dr Kate Jeffery’s paper 0ct 2017

Dr Kate Jeffery is one of our heroes and has a lab at University College London where she experiments with what the brain is doing when rats navigate around a maze. In her experimental rig, she can see neurons fire up as the rat faces in different directions (head direction cells) while it is exploring. These head direction cells as the rat moves its head to each direction (each cell has its own preferred direction). So this provides an on-board compass that is not magnetic, but rather uses the visual world combined with information about movements. As we have described elsewhere landmarks are critical to navigation as they recalibrate the other navigational inputs and give a fix, while self-motion information allows the compass to be updated.

Her latest paper covers the problem of a rat navigating in three dimensions.

In a nutshell, the question is whether an animal (or indeed a human) can get away with a flat compass in a 3D world, given that a compass only gives you 360 degrees of direction but 3 dimensional space is 360 x 360 x 360 degrees (one for each plane – horizontal, North-South vertical and East-West vertical), which would be a lot more neurons for the brain to have to make. In addition, most of the neurons would also be silent most of the time, which is wasteful of the energy needed to keep cells alive. However, if you only have a flat compass that tracks yaw (head direction) rotations, then if you go around vertical corners, the compass ends up pointing the wrong way. Jeffery’s team showed that you can avoid this error if you adjust the compass to account for rotations around vertical corners (or indeed, any type of rotation around a vertical axis – not necessarily a corner).

So, the team propose two rules, one rule for adjusting the compass when you turn left or right in the body plane in the usual way, and a second one that adds an additional correction of the whole body plane itself rotates around a vertical axis. In this way, one could, for example, walk right around the side of a hill without turning left or right, and yet still have an appropriately updated compass.

Prof Jeffery’s team did some simulations to show this works in principle. They then recorded head direction cells from real rats navigating around the vertical corners of a cube and showed that they indeed seem to update according to this rule. Thus, it’s possible that rats, and maybe other animals, can use a flat compass when moving over non-flat surfaces, provided they use this dual-axis rule, without needing to make a lot of neurons and without accruing errors.

In addition to a compass, the rats, as all good navigators, must have a way of measuring distance (odometer). To do this they probably use several things – footfall, optic flow, vestibular signals. These are processed in another part of the brain by a different type of neuron called grid cells – more on these another time.

Please follow the link : http://jn.physiology.org/content/jn/early/2017/10/06/jn.00501.2017.full.pdf

Prof Kate Jeffery has kindly helped me understand some further truths about animal navigation. These are not proved but seem to stand up to investigation. For humans, it isn’t just head-on-neck turning, it is anything that rotates the whole head in space that is what helps guide navigation. You’ll find that in the course of a day you face pretty much all directions without becoming disoriented, even when going over and around hills, so that her work investigates how this is achieved.

In summary we are beginning to tease out how animals navigate but we are still far from understanding how migratory species and long distance travellers know where they are going.

Richard Nissen
Editor

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The Albatross

You will find other descriptions here of Henri Weimerskirch’s work on Albatrosses under Albatrosses on this site as well as Anna Gagliardo’s work on the use of smell in navigation.

A book recently written by Adam Nicholson called “The Seabirds Cry” is fascinating about the mythology and lives of the sea birds in his book; he covers Fulmars, Puffins, Kittiwakes, Gulls, Guillemots, the Cormorant and Shag, the Shearwater, Gannet, the Great Auk and its cousin the Razorbill, and the albatross.

You will see his book reviewed on the home page under “book reviews”

He is a great expert and lover of seabirds and talks about the work that many of scientists working in the animal navigation field have covered.

I particularly like his discussion about the wandering albatrosses and the way that they cannot really operate without the wind to keep them aloft. He quotes Gabrielle Nevitt who discovered that a lot of these Seabirds (including the Albatrosses and Shearwaters use their acute small to find their prey just like the land based vultures). They cruise around until they find the smell the rotting squid, which they feed on, then drop down to take. This is why so many are killed by Tuna long lines bated with squid. They smell the squid, from as much as 15 miles away and then get snared by the hooks and drown. One way of dealing with this menace is to bait the line at night when the albatross sits on the sea and does not hunt. However, bright moonlight nights give the albatross the light they need to fly.

Albatrosses range over the entire southern oceans as they take advantage of the various weather fronts, whose winds take them effortlessly, they lock and hang from their wings gliding using almost no energy with a low pulse rate.

In a New Scientist article (14 October 2017) Abdessattar Abdelkefi and his team from New Mexico State University discovered that the black top sides of the Albatross as opposed to its white underside meant that the top of the bird was heated by about 10C giving the bird added lift.

The birds can use the Northerly winds to take them south and the Westerlies (the roaring 40s) to reach and finally the Southerlies to get home. They are always on the prowl for food but seem to be able to ride the winds to come home to their nesting islands of le Crozet. For an albatross, gliding in high winds takes no effort so a journey of 8000 miles is of nothing to them. Over their lives of up to 80 years they will cover millions of miles.

The question about how they find their home again to breed remains the same mystery as for other wandering and migrating animals. It is certain that Albatrosses and Sheerwaters use their highly developed sense smell to hunt and navigate by. Anna Gagliardo sent some Cory’s Sheer into the middle of the Atlantic Ocean and those whose sense of smell was deprived got lost and the others not. But how does the sense of smell help navigate in the ocean where I imagine the location of smells are changing all the time? Of course smell can get them to their breeding places when they are near enough. For me it all to do with the different stages of navigation and how all navigators use as many signals as possible, as well as, different ones at different stages in their journeys.

Richard Nissen
Editor October 2017

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Conversations about animal navigation…

At a recent meeting of the Royal Institute of Navigation I met Jon Ward.

Jon was brought up in Africa as a boy and spent much time roaming the countryside and going to distant villages out of sight of his home.

We talked about Animal navigation and I told him that I thought that as humans are animals too, animals are likely to use the same methods to navigate by as we do when we do not rely on instruments.

Work by Prof Kate Jeffery of University College London tells us that her rats have an on-board compass which is a hemispherical display of neurons which operates when the rat turns its head. With head direction known and an odometer of the distance travelled you have a dead reckoning system.

Other enquiries of mine have discovered that indeed navigation without instruments is not a cognitive operation. It is not carried out by the conscious front cortex but rather the sub conscious. In prof Jeffery’s rats in the navigational area is inside the hippocampus (part of our subconscious). This is born out with my discussions with native people who simply cannot describe how they navigate through difficult terrain which is often featureless or it is dark.

Jon and others I have spoken to said they never go lost on their journeys when he was younger and were never worried that they would. But he adds that when a person is alone that is the test of confidence, the navigator must then use their own ideas ‘whatever they are’ to get from A – B, primitive people grow up learning these skills from their elders and often the skills relate to only their area of need, moving cattle, hunting for food, navigating between islands, some of these trips may take days to accomplish. The navigator may have no concept of North and East or South and West, but his survival is dependant on different elements. After all that is what is important to him.

He made some very interesting observations about his journeys though, He said he was always very conscious of the time of year and therefore where the sun would be at different times.

Jon explained that an acute sense of smell was very important. For instance he could smell grasses and know that they were in the shade of had not been heated by the sun because of their smell. This sort of information gives you orientation

There has been a lot of work by Italian teams such as Anna Gagliardo of the Department of Biology Pisa, Italy.  For instance, they have released Shearwaters about 400 km from their home colony and birds made anosmic by washing the olfactory mucosa with zinc sulphate, which destroys specifically olfactory neurons.  The birds where the olfactory neurons were destroyed got lost and never made it home.  Gagliardo also says that homing pigeons use olfaction for navigation. So I am sure that it is these sort of olfactory cues that the birds use too, recent work on other sea birds seems to underline smell as an important navigational tool especially in the featureless (to us) ocean.

We must remember that all navigators use all the information available to them all the time and if some clues are missing then you rely on others as you can. It seems that landmarks are very important.

Talking to the Sami people in the featureless north of Sweden (in the winter) these used topography and the prevailing wind to navigate by.

Jon is interesting in that he later joined the Navy (before GPS) and was in charge of getting his ship home from At a recent meeting of the Royal Institute of Navigation I met John Ward

John was brought up in Africa as a boy and spent much time roaming the countryside and going to distant villages out of sight of his home

We talked about Animal navigation and I told him that I thought that as humans are animals too, animals are likely to use the same methods to navigate by as we do when we do not rely on instruments.

Work by Prof Kate Jeffery of University College London tells us that her rats have an on-board compass which is a hemispherical display of neurons which operates when the rat turns its head. With head direction known and an odometer of the distance travelled you have a dead reckoning system.

Other enquiries of mine have discovered that indeed navigation without instruments is not a cognitive operation. It is not carried out by the conscious front cortex but rather the sub conscious. In prof Jeffery’s rats in the navigational area is inside the hippocampus (part of our subconscious). This is born out with my discussions with native people who simply cannot describe how they navigate through difficult terrain which is often featureless or it is dark.

John and others I have spoken to said they never go lost on their journeys when he was younger and were never worried that they would. But he adds that when a person is alone that is the test of confidence, the navigator must then use their own ideas ‘whatever they are’  to get from A – B, primitive people grow up learning these skills from their elders and often the skills relate to only their area of need, moving cattle, hunting for food, navigating between islands, some of these trips may take days to accomplish. The navigator may have no concept of North and East or South and West, but his survival is dependant on different elements. After all that is what is important to him.

He made some very interesting observations about his journeys though, He said he was always very conscious of the time of year and therefore where the sun would be at different times.

John explained that an acute sense of smell was very important. For instance he could smell grasses and know that they were in the shade of had not been heated by the sun because of their smell. This sort of information gives you orientation.

There has been a lot of work by Italian teams such as Anna Gagliardo of the Department of Biology Pisa, Italy.  For instance, they have released Shearwaters about 400 km from their home colony and birds made anosmic by washing the olfactory mucosa with zinc sulphate, which destroys specifically olfactory neurons.  The ones where the olfactory neurons were destroyed go lost and never made it home.  Gagliardo also says that homing pigeons use olfaction for navigation. So I am sure that it is these sort of olfactory cues that the birds use too, recent work on other sea birds seems to underline smells as an important navigational tool especially in the featureless (to us) ocean.

We must remember that all navigators use all the information available to them all the time and if some clues are missing then you rely on others as you can. It seems that landmarks are very important.

Talking to the Sami people in the featureless north of Sweden (in the winter) these used topography and the prevailing wind to navigate by.

John is interesting in that he later joined the Navy (before GPS) and was in charge of getting his ship home from At a recent meeting of the Royal Institute of Navigation I met John Ward.

John was brought up in Africa as a boy and spent much time roaming the countryside and going to distant villages out of sight of his home.

We talked about Animal navigation and I told him that I thought that as humans are animals too, animals are likely to use the same methods to navigate by as we do when we do not rely on instruments.

Work by Prof Kate Jeffery of University College London tells us that her rats have an on-board compass which is a hemispherical display of neurons which operates when the rat turns its head. With head direction known and an odometer of the distance travelled you have a dead reckoning system.

Other enquiries of mine have discovered that indeed navigation without instruments is not a cognitive operation. It is not carried out by the conscious front cortex but rather the sub conscious. In prof Jeffery’s rats in the navigational area is inside the hippocampus (part of our subconscious). This is born out with my discussions with native people who simply cannot describe how they navigate through difficult terrain which is often featureless or it is dark.

John and others I have spoken to said they never go lost on their journeys when he was younger and were never worried that they would. But he adds that when a person is alone that is the test of confidence, the navigator must then use their own ideas ‘whatever they are’  to get from A – B, primitive people grow up learning these skills from their elders and often the skills relate to only their area of need, moving cattle, hunting for food, navigating between islands, some of these trips may take days to accomplish. The navigator may have no concept of North and East or South and West, but his survival is dependant on different elements. After all that is what is important to him.

He made some very interesting observations about his journeys though, He said he was always very conscious of the time of year and therefore where the sun would be at different times.

John explained that an acute sense of smell was very important. For instance he could smell grasses and know that they were in the shade of had not been heated by the sun because of their smell. This sort of information gives you orientation

There has been a lot of work by Italian teams such as Anna Gagliardo of the Department of Biology Pisa, Italy.  For instance, they have released Shearwaters about 400 km from their home colony and birds made anosmic by washing the olfactory mucosa with zinc sulphate, which destroys specifically olfactory neurons.  The ones where the olfactory neurons were destroyed go lost and never made it home.  Gagliardo also says that homing pigeons use olfaction for navigation. So I am sure that it is these sort of olfactory cues that the birds use too, recent work on other sea birds seems to underline smells as an important navigational tool especially in the featureless (to us) ocean.

We must remember that all navigators use all the information available to them all the time and if some clues are missing then you rely on others as you can. It seems that landmarks are very important.

Talking to the Sami people in the featureless north of Sweden (in the winter) these used topography and the prevailing wind to navigate by.

John is interesting in that he later joined the Navy (before GPS) and was in charge of getting his ship home from Cape Town to just south of the Canaries. The ship was enveloped in fog for several days so there was no possibility of a sextant sight. But when he was able to check his position he found that the dead reckoning that he had been working on had not let him down and he was where he thought he should be.

There are many examples of people who said that they had a great “sense of direction” being completely disorientated by trying to navigate in the southern hemisphere when they had lived their lives in the Northern one. Jon’s other important point is that aborigine navigators work well in their home range. Wilfred Thesiger, the explorer, found that when crossing the empty quarter in Arabia he had to use his compass to find his way and save them from certain death as the native guides were lost as they were not in their territory.

There is no magic method for navigation but the clever use of all the information that is at hand. It seems the people best at navigation with a sense of direction are probably the best at reading the landscape and collecting all the available information. We must remember that the Australian Aborigines used song lines and the Polynesians also use the stars to navigate by.

Jon Ward and Richard Nissen
October 2017

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Successful acceptance test of the ICARUS qualification model

This site takes you into the world where technology is trying to understand animal migration by using tags and a sophisticated satellite system to follow routes taken by animals.  Up until now tags have often been very heavy, or at least too heavy for a lot of tiny birds that make huge migrations such as the cuckoo. Other tracking has used daylight length so that during the equinox when birds ofter migrate they are inefficient.  Papers have been written on very incomplete evidence such as 4 individuals.  The Icarus project will deliver enormous amounts of data which should enable us to understand these animal movements better.
Richard Nissen
editor
Posted in Animal Migration, Bird Navigation, Sense of Direction | Comments Off on Successful acceptance test of the ICARUS qualification model