61. New light on dancing bees…

Thanks to the pioneering work of Karl von Frisch, we have long known that honey bees returning to the hive can communicate both the distance and the direction of a food source to their hive-mates.

They achieve this astonishing feat by means of a curious ‘waggle dance’ they perform on the vertical surface of the hive - in complete darkness. To make sense of the dance, the ‘followers’ need to be able to do two things. They must keep track of the orientation of the ‘dancer’ relative to the vertical force of gravity (this supplies the course or vector that leads to the food source, relative to the sun’s position in the sky) and also monitor the duration of the dance (which supplies the distance the bee will have to travel to the food source).

For a long time researchers have wondered how the ‘followers’ - who surround the ‘dancer’ on all sides - can possibly keep track of the complicated patterns of the dance.

Ingenious new research by Anna Hadjitofi and Barbara Webb suggests a possible answer.

High speed video recordings reveal that the ‘followers’ adjust the angles of their antennae depending on where they stand in relation to the ‘dancer’.

In principle, if the ‘followers’ knew their own body angle relative to the ‘dancer’ (as encoded in the position of their antennae) and combined that with their heading relative to the vertical force of gravity, they could work out where the food source lies.

Hadjitofi and Webb have shown that navigational circuitry of just the kind employed by fruit flies would enable honey bees to perform all the necessary computations. (The details are a bit complicated - for a full explanation, follow this link to the original research.)

Since honey bees and fruit flies are very likely to share the same navigational circuitry, it is highly probable that Hadjitofi and Webb are onto something really important. But further research will be needed to establish whether they are correct.

60. Butterflies cross an ocean

Research just published shows that migratory Painted Lady butterflies (Vanessa cardui) found on the coast of South America had crossed the Atlantic from West Africa - and might even have started their journeys in Europe. That means they may have travelled - in total - 7000 km or more! Astonishing, even by comparison with the mighty Monarch butterfly, though the Painted Ladies would have been helped on their way by the Trade Winds.

Painted Lady butterfly

59. The Challenge of Light Pollution

Our abuse of the natural world is causing problems which grow more terrifying with every passing day.  

Understandably, climate change and the physical destruction of entire ecosystems attract the most attention. 

But we face another environmental threat - one which is insidious and fast-growing, yet still widely ignored. 

Light pollution.

The world we inhabit was, until modern times, governed by strict astronomical laws. Day followed night, and the night was always dark - except when the moon was full. This celestial regime shaped the behaviour and biological rhythms of (almost) every living thing on the planet. 

The coming of electric light changed everything - and continues to do so. In many places true darkness now never comes. And while we may welcome that change because some of our deepest fears are associated with darkness, all that new light is causing immense damage. 

There is overwhelming evidence of the destructive effects of artificial light on the animals (and plants) with which we share the planet. 

To give just a few examples, it is likely that billions - yes, billions - of migratory birds die when they are drawn to brightly lit buildings. And even that number is dwarfed by the number of insects that suffer a similar fate. Then there are the countless, doomed turtle hatchlings that are lured away from the sea by artificial light.  

Light pollution is a major but little-noticed factor in the massive problem of biodiversity loss. 

Moreover it is increasingly clear that by banishing darkness we are also damaging our own health and well-being.

Exposure to artificial light at night is associated with a host of physical and mental disorders including diabetes, depression and even some forms of cancer.

And we are suffering other, less tangible but important injuries.

The darkness that once permitted everyone on the planet to see thousands of stars, as well as the glowing ribbon of the Milky Way - our home galaxy - has been obscured by the halo of artificial light that surrounds every town and city. The arrival of the LED has only made matters worse.

Most people living today will never see the night sky in all its glory. 

The facts are not in dispute.  In some countries (France, for example) governments are already taking practical steps to address the problems of light pollution. In the US there are many cities that have taken steps to reduce the glare of outdoor lighting.

But the British government rejected an amendment to the recent Environment Act that would have added the reduction of light pollution as a target. 

Low public awareness is a major obstacle, coupled with the common assumption that more light must be better, and a widely held (but questionable) belief that it always improves our security.  

Few people realise that the worst effects of light pollution can be reduced or eliminated by taking a few simple, inexpensive steps - such as installing lights with warmer colours, shielding them so that they don’t not spill upwards into the sky, and using motion sensors so that they only come on when needed. 

The best solution of all - just turning unnecessary lights off - has the great additional benefit of saving both energy and money.  

Often it is enough to draw someone’s attention to the problems. I recently persuaded the British Army to remove some outrageously bright lights from a military base in the middle of Chichester Harbour (a nature reserve on the South Coast of England) simply by having a conversation with the senior officer in charge. 

In the UK, the Council for the Protection of Rural England’s (CPRE) annual ‘star count’ has helped people become more aware of the problem of ‘skyglow’ - and it’s good news that several Dark Sky Parks have been designated in the UK.  

But while some UK charities take an interest in light pollution, none treats it as a priority. Because all their efforts are small and fragmented, progress in tackling the problem has been painfully slow.

 Much more needs to be done. 

 So here are a few ideas: 

Why don’t British environmental charities devise and adopt a code of conduct in relation to light pollution? 

Why don’t those same charities ask all their grant recipients to follow a similar code of conduct? Perhaps they could offer extra funding for this purpose. 

A good way of raising public awareness in the UK would be to establish an annual prize in recognition of outstanding achievements in tacking light pollution. Who would like to take this on? 

Above all, policy change is needed. Will one of our leading environmental charities launch a campaign to get the government to regulate light pollution? 

Yes, it’s a big challenge, but it’s also an urgent one.  

58. New National Geographic channel series: INCREDIBLE ANIMAL JOURNEYS

This spectacular - and very beautiful series - is now available on Disney + and if you’re interested in animal journeys you’ll really want to watch it!

I was asked to help the production team at Plimsoll Productions and had fun trying to answer their questions about the navigational tools employed by a pretty diverse set of animals.

It was very nice to be given an on-screen credit as a ‘series consultant’!

52. The wonder of whiskers →

Part of the charm of a seal is its whiskery face, but those whiskers are not just decorative. A fascinating new article reveals that they are astonishingly sensitive and can be used to track prey over long distances.

It’s long been known that seals (Phocidae) use their whiskers to detect things underwater - a useful skill, especially when visibility is reduced to zero. But until recently nobody knew just how sensitive they were. It now appears that they can pick up the turbulence left in the wake of a herring swimming 180 meters away!

A seal’s whiskers are obviously exquisitely sensitive - and are therefore well supplied with sensory nerves. But that’s not the whole story. The shape of their whiskers also seems to be significant. Rather than being simple, tubular structures like a human hair, they have curious undulating contours along their length. These increase their ability to detect the minute vortices that persist for a long time after a fish has swum by.

Scientists are interested in harnessing these discoveries to develop ‘autonomous underwater vehicles’ (i.e. robotic submarines) that can mimic the seal’s amazing tracking skills. No doubt the military are paying attention too.

51. The night sky and the problem of light pollution

I spent the month of July sailing from Southern Greece to Northern Spain - a 2000 nautical mile voyage in a 14-meter yacht.

It was the first time I’d been out of sight of land since the start of the COVID pandemic.

As we headed across the Ionian Sea to Siracusa, I saw a red sun disappear beneath the horizon with the briefest wink of green light. The so-called ‘green flash’ - so rarely seen that some doubt its reality!

On watch that night I was treated to the sublime spectacle of a truly dark night sky, unpolluted by artificial light - stretching from horizon to horizon.

The arch of the Milky Way glowed above us and the occasional meteor briefly slid across the sky. Jupiter and Saturn rose slowly in the east, Antares glowed low in the south, Arcturus descended towards the western horizon, and Cassiopeia looked down on us from her throne in the northern sky.

A mysterious rain fell from that cloudless sky - a rain of wonder and peace - and I felt a strange, spine-tingling joy.

Among all the many precious things threatened by our reckless and greedy commitment to what economists and politicians call ‘growth’, is the darkess of the night.

Most of us now live in towns and cities where artifical light veils all but the brightest stars. And the plague is spreading ever wider. The night we see is quite different from that with which all our ancestors were familiar. Different, and profoundly impoverished.

Yet unlike many of the environmental problems we face, light pollution is relatively easy to fix.

It’s not difficult to turn off the many lights that serve no useful purpose, and it’s easy to shield those that we really need so that their light isn’t wastefully poured into the sky.

Light pollution is a serious threat to the welfare of many of the creatures with which we share the planet - from migratory birds and insects, to amphibians, crustaceans, reptiles and even plants. And there’s a strong body of evidence that it’s bad for our health too.

Of course reducing light pollution would also save a great deal of money as well as reducing energy consumption and CO2 emissions.

The UK Parliament is currently considering a new Environment Bill which contains a number of key targets. Bafflingly, however, reducing light pollution is not yet among them.

The UK charity Buglife has been working hard, in collaboration with others, to change that, but they need all the help they can get.

If, like me, you want to see light pollution reduced, why not lend Buglife your support? You can do so by joining as a member or by writing to your MP (if you live in the UK) to support their proposed amendment to the Envirnoment Bill.

You might also be interested in supporting the impressive work of the excellent US-based International Dark Sky Association.

49. Thoreau - on being lost

‘It is a surprising and memorable, as well as valuable experience, to be lost in the woods at any time.  Often in a snow-storm, even by day, one will come out on a well-known road and yet find it impossible to tell which way leads to the village. Though he knows that he has travelled it a thousand times, he cannot recognise a feature in it, but it is as strange to him as if it were road in Siberia. By night, of course, the perplexity is infinitely greater. In our most trivial walks we are constantly, though unconsciously, steering like pilots by certain well-known beacons and headlands, and if we go beyond our usual course we still carry in our minds the bearing of some neighbouring cape; and not till we are completely lost, or turned around - for a man needs only to be turned round once with his eyes shut in this world to be lost - do we appreciate the vastness and strangeness of Nature. Every man has to learn the points of compass again as often as he wakes, whether from sleep or any abstraction.’

Henry David Thoreau, Walden (The Village).

48. How can creatures without brains remember where things are?

You might well suppose that the ability to keep track of where things are depends on having a brain of some kind - or at least a nervous system

But you would be wrong. Not only can single-celled organisms find their way towards things they need (like food) and away from things they don’t like (such as too much heat), but some of them can also remember locations. This is of course a key navigational task.

One fascinating class of single-called critters - with the unappetising name of slime moulds - has long been known for its ability to build highly efficient transport networks. As I mentioned in Incredible Journeys/Supernavigators, these giant, unicellular organisms can even solve a problem that has taxed the brains of human engineers: how to create the most efficient rail network connecting a number of cities and towns of different sizes.

Until now it has not been entirely clear how slime moulds achieve these feats. But a new study reveals how these apparently simple organisms can ‘remember’ the things that most matter to them.

Slime moulds are in the business of building tubes for moving nutrients around (just as railroads are used for moving people or goods). It seems that they respond to the presence of food by expanding the diameter of the tubes they build. The richer the source, the bigger the tube leading to it. Information about nutrient locations is therefore encoded directly in the physical structure of the tube network. It is a kind of associative memory.

As the researchers put it, ‘nutrient location is stored in and retrieved from the networks’ tube diameter hierarchy’. Their findings help to explain ‘how network-forming organisms like slime molds and fungi thrive in complex environments’. Since slime moulds and fungi are now known to perform a wealth of vital tasks, this is an important discovery.
What’s more, it may prove helpful to human network designers.

45. How to make electronic navigation more engaging - and rewarding

Many navigators are worried about the consequences of our increasing reliance on automatic navigation systems - especially the ‘turn-by-turn’ apps based on GPS that are now embedded in every cell phone and every vehicle.

There’s plenty of evidence (which I discuss in Incredible Journeys/Supernavigators) that the passive use of these apps impedes the development of the mental maps that enable us to find our way around most efficiently.

There are even those who think that we may endanger our overall cognitive health by using them too much. And there’s no doubt that these apps impoverish our lives by discouraging us from taking an active interest in the world around us.

But nobody seriously thinks we can turn the clock back. Navigational apps are here to stay because they make life so much easier - and sometimes (though not always) safer.

The question is whether they can be tweaked so as to reduce or eliminate some of their drawbacks.

An interesting new study (Clemenson, G.D., Maselli, A., Fiannaca, A.J. et al. Rethinking GPS navigation: creating cognitive maps through auditory clues. Sci Rep 11, 7764 (2021). https://doi.org/10.1038/s41598-021-87148-4) examines the virtues of a different kind of app - one that does seem to help people develop a better grasp of the layout of their surroundings.

Instead of relying on the usual turn-by-turn directions, some participants in the new study followed a virtual, auditory compass (based on the Soundscape app - originally designed for visually-impaired users) in order to locate various goals dotted around the Microsoft campus. The compass indicated the straight-line route to each goal, and the user then had to navigate actively around any obstacles (like buildings) that stood in the way.

The authors acknowledge that the sample size was small, but they insist that - in contrast to a standard turn-by-turn app - the Soundscape virtual compass helped participants who were new to the campus develop a better sense of its geography.

They argue that “using auditory beacons to navigate can lead to greater explorative behavior and the formation of more accurate mental maps of the surrounding environment when compared to turn-by-turn navigation. Thus, demonstrating that it is possible to use GPS technology and promote learning through active navigation.”

They conclude that an auditory beacon is “a sensory augmentation that helps us create a stronger connection with our environment.”

This is a promising development, and I hope we’ll soon see more research of this kind. But I wonder whether the mass market navigational platforms will take heed of the new findings - and whether users are ready to embrace a more active approach to navigation than they have got used to. We’ll have to wait and see.

44. Where the Wild Things Go: New Yorker article

The latest edition of The New Yorker magazine (5 April 2021) carries an excellent article by Kathryn Schultz. It’s a review of the science of animal navigation based on her careful reading of several recent books on the subject, including my own Supernavigators. As you might expect from a Pulitzer Prize-winning writer, it’s lucid and elegant - and well worth a read.

42. Dust Devil - a beautiful short film about art and our place in nature

I’ve just seen a beautiful and touching short movie by a brilliant film-maker: Poppy Walker.

It was released in 2019 and it’s called Dust Devil - and it’s won a lot of prizes. It concerns the dancer, Marta Becket, and her extraordinary efforts to restore and maintain a theatre on the edge of Death Valley.

It doesn’t have much to do with navigation, but I want to share it because it says something profound about a subject that matters a lot to me: the deep connections between people and the natural world, and how these find expression in works of art.

It only lasts 9 minutes - do watch it!

41. Christiane Ritter on the Polar night - and the glory of the sun

In 1934, a young Austrian artist - Christiane Ritter - did something a bit crazy. She left behind her comfortable home and went to live with her husband and another man (both hunters), in a tiny hut at Gray Hook, on the northern shores of Svalbard - just 600 nautical miles from the North Pole. They spent the whole winter there and she wrote a remarkable book about the experience which, in translation, is called A Woman in the Polar Night (translated by Jane Degras and published by Pushkin Press). First published in German in 1938, it really deserves to be better known.

The hut at Gray Hook (follow the link to explore panoramic view)

Just to give you a taste, here’s a powerful passage about the psychological effects of the long Polar night - and dreams of the glorious, returning sun:

Now everything around us is quite dead; even the battering of the storm has ceased. A heavy mist weighs on everything; the hut is shrouded in stillness and darkness. It seems to me as if only now has the real night fallen, and slowly my courage begins to seep away. Perhaps the sun will never come back again. Perhaps it is dark all over the world.

My husband calms my fears. Again and again, on little scraps of paper, he marks the course of the sun, which since 23 December has been on its way back to us…. But I am in despair. All his explanations tell me only how far away the sun is. There is no glimmer of light to show that it is coming nearer, and although 78 days of darkness have already passed, there are still another 54 days before, for the first time, the sun will peep for a few seconds over the southern horizon…

The days pass uneventfully, without any real work, without a consoling glimpse into the reality of the world. At night we lie down, neither tired nor wakeful, encompassed by the unending darkness and the profound quiet.

Surrounded by this boundless deadness and rigidity of everything physical, one's living senses begin slowly to go their own way. More frequently and more brightly as the winter is prolonged, a strange light spreads before the inner eye, a remote and yet familiar vision. It is as though here, in this apartness, we develop a particularly sharp awareness of the mighty laws of the spirit, of the unfathomable gulf between human magnitudes and eternal truth. Outside of time, everything is annihilated. The imprisoned senses circle in the past, in a scene without special dimensions, a play in which time stands still.

Often I see the flowers and trees of the distant sun world, but I do not see them as I used to see them. They are glowing with colour and piercingly beautiful. Their most secret meaning lives in their growth and their colour. But the people who live under the sun seem distant and small to me. With bent heads they are running round in circles, the circles of their anxieties and troubles. Only a few of them see the glory of the sun.

38. In memory of Barry Lopez

One of the oldest dreams of mankind is to find a dignity that might include all living things. And one of the greatest of human longings must be to bring such dignity to one’s own dreams, for each to find his or her own life exemplary in some way. The struggle to do this is a struggle because an adult sensibility must find some way to include all the dark threads of life. A way to do this is to pay attention to what occurs in a land not touched by human schemes, where an original order prevails.

The dignity we seek is one beyond that articulated by Enlightenment philosophers. A more radical Enlightenment is necessary, in which dignity is understood as an innate quality, not as something tendered by someone outside. And that common dignity must include the land and its plants and creatures. Otherwise it is only an invention, and not, as it should be, a perception about the nature of living matter.

From the last chapter of ‘Arctic Dreams’, the masterpiece of Barry Lopez (1945-2020) who died on Christmas Day in Eugene, Oregon.

34. How cells can successfully navigate a microscopic Hampton Court maze... →

It’s long been known that cells can navigate towards chemicals that attract them by following concentration gradients. This process is known as chemotaxis.

But this simple form of navigation isn’t equal to the task of guiding cells over long distances (more than 1 mm) or along a tortuous, branched paths - which is exactly what we see, for example, when an embryo is developing, during an immune response or when a tumour is metastasising.

So how is any of that possible?

New research suggests that it depends on a process called ‘self-generated chemotaxis’.

The idea is that, rather than passively responding to the presence of a chemical attractant, some cells actively alter their environment by breaking the attractant down as they move along. The local depletion of the attractant results in diffusion of fresh attractant towards the cells from its source. This dynamic flux, rather than the absolute amount of attractant around the cells, seems to be the key to the whole process. In effect, the cells create their own local chemical gradients and use these as a basis for choosing their direction of travel.

Luke Tweedy and his colleagues set a tough pathfinding challenge for cells of an organism called Dictyostelium discoideum (known for its long-range navigational ability), as well as metastatic pancreatic cancer cells. They had to find their way through a variety of mazes, some of which were quite complex. One of them was actually based on the famous maze at Hampton Court Place.

Remarkably enough, the cells could efficiently find optimal routes, detect dead ends before they reached them, and could sense an approaching junction, even when it was around a corner!

Significantly, these experimental results were accurately predicted by a computer model - which means that they probably apply to any system in which an attractant is degraded by cells that are drawn towards it.

The authors believe that self-generated chemo-attractant gradients ‘could offer answers to many unexplained physiological behaviors’.