According to MacRury, it wasn’t until his apprenticeship among hunters ended and he began running his own dogs that he started to realize how critical Inuit dogs were to finding one’s way. Again and again he discovered that some of his dogs had uncanny abilities to navigate in any condition. “I had some wild experiences in total blizzard conditions, and the dogs would get you home. They seem to have a sense that we’re going home and it’s in this direction and they follow it. I’m sure they never deviated five feet from the trail, and yet I couldn’t see a thing.” Not all his dogs had this capacity; some were better than others. “They are not all cookie-cutter types, they have very distinct abilities,” he explained. But the Inuit have been ruthlessly weeding out dogs from the breeding pool for hundreds of generations, producing what MacRury called simply a “pretty amazing animal.” He trusted their memory to such a great extent that in blizzard conditions he stopped directing his dogs and simply let them go, confident that they would take him home even if there was no trail on which to backtrack. Indeed, his lead dogs were often able to take shortcuts in the dark across miles of unknown country until they picked up a main trail leading into Iqaluit. The feats MacRury described seemed to rely on the creation and retention of incredibly specific and detailed cognitive maps. But do dogs have them? John MacDonald told me that around Igloolik there is a word for this capacity to unfailingly know where one is regardless of external conditions, and that it can apply to both people and dogs: aangaittuq. “The term can be translated as ‘ultra-observant,’” explained MacDonald. Its opposite is aangajuq, a term for “one who moves away from the community and immediately loses where his destination is at, so as a result will travel blindly.”
In the 1970s a behavioral psychologist at the University of Michigan argued that wolves do have cognitive maps. Roger Peters spent several years observing wolves in the wild and came to believe that they could create maps with a level of skill not usually granted to nonhuman animals. Furthermore, the shared capacity for cognitive mapping between men and wolves was not a coincidence. Both species evolved as social hunters of big game, meaning they formed groups and traveled over large areas of space in pursuit of prey, then returned to their young, pack, or camp. He estimated that the range of wolves and men was about the same: both could travel around a hundred miles in twenty-four hours. “Men and wolves have both had millions of years to evolve solutions to the problems of getting lost, where ‘lost’ means separation from your fellow-hunters, not knowing a quick way back to your young, or where your prey is headed.” Peters didn’t think this was a map in the sense of an aerial view but a simplification of the environment insofar as the brain threw away unnecessary information and retained and organized other elements, such as the locations of dens, feeding grounds, water, food caches, shortcuts, and predators and the spatial relationships between them. For wolves, these maps were particularly dependent on olfactory cues, which Peters noted were a much more important and vivid part of a wolf’s world than humans could imagine. “For wolves, the reality of an object may lie much more in its smell than in its visual properties,” he wrote. Peters knew from his field research that wolves marked their path every three hundred meters on average, and particular attention was paid to junctions—the intersection of paths that would most often serve as rendezvous sites with others in the pack. The wolves were creating nodes, turning an otherwise blank landscape into a network of landmarks.
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Though it was early morning, the sun had already been up for eight hours, showering the land in fluorescence. It was cold enough that I pulled my arms in from the sleeves of the anorak to hug myself, and in this compact form I began walking up the rocky hillside behind the cabin, sinking in pockets of snow and stepping over foot-high willow trees like a giant in a forest. Small as the trees were, some were likely over a hundred years old; most grow just a tenth of a millimeter a year in the Arctic. I was hoping to catch sight of snow geese arriving at this spit of land after a three-thousand-mile journey along an invisible avian superhighway with five hundred other bird species, each getting off at their respective feeding, breeding, and nesting places.
Inuit taxonomy classifies life under three categories: anirniliit, those that breathe; nunarait, things that grow; and uumajuit, which includes everything that moves. Some uumajuit are tingmiat, those that fly, and others are pisuktiit, the walkers. This last category is where humans belong, alongside caribou and musk ox. Snow geese are tingmiat and precious to hunters, who anticipate their arrival for weeks each spring. In Iqaluit I saw twelve-year-old kids with shotguns strapped across their chests riding snowmobiles off into the hills to look for them. Two young hunters, intoxicated with the possibility of shooting geese, told me how they had recently driven 120 miles on their snowmobiles in the hopes of finding some. When the geese start to arrive en masse, hunters can easily shoot sixty or more birds over a day to eat, freeze, and share. Now I searched for them in the silent moonscape, moving to stay warm.
Life on earth has created millions of Ulyssean species undertaking epic journeys at scales both large and small. Getting lost is a uniquely human problem. Many animals are incredible navigators, capable of undertaking journeys that far eclipse our individual abilities. The greatest migration on earth belongs to the Arctic tern, a four-ounce argonaut that travels each year from Greenland to Antarctica and back again, a distance of some forty-four thousand miles. Flying with the wind, the tern’s return itinerary is a globe-trotter’s fantasy, circumnavigating Africa and South America. Sooty shearwaters fly over thirty-nine thousand miles, zipping around the Pacific Ocean in figure eights to take advantage of prevalent winds. The ornithologist Peter Berthold estimates that half of all known bird species—fifty billion birds in all—migrate each year. Epic journeys are not limited to the feathered tribes. Undulating herds of zebras and wildebeests travel across the Serengeti to follow the rain. Leatherback turtles leave the coast of California and swim to Indonesia ten thousand miles away, and then make their way back again to the same beaches where they were born.
The lesser-known journeys are no less spectacular. The word plankton was coined by a German physiologist from the Greek plazesthai, meaning to wander or drift, and describes the tiny microorganisms that are carried by the ever-moving mass of the ocean. But plankton’s random perambulations are only horizontal. Every twenty-four hours, trillions of these organisms, billions of tons of biomass in total, undertake an intentional vertical migration, rising to the surface of the ocean at twilight and descending at sunrise. Are these plankton similar to the first organisms that moved? Not the first to be swayed, pushed, flung, or caught by air or water, but the first to move from one place to another by their own volition? The earliest vertebrates, according to the authors of The Evolution of Memory Systems, developed a homologue to the hippocampus, giving them a navigation system that worked in tandem with older reinforcement systems. As they put it, this system guided behavior by linking stimuli and actions to biological costs and benefits, and just about all behavior in these ancient ancestors involved navigation: foraging, predator avoidance, temperature regulation, and reproduction. In order to survive, animals couldn’t just move randomly but had to wayfind from one specific place to another, a demand that has resulted in a diversity of navigation mechanisms in nature.
Scientists have conceptualized this diversity as evolution’s navigational toolbox. This idea was presented in 2011 by ten prominent scientists, including Kate Jeffery and Nora Newcombe, who study both animal and human cognition and behavior in the hopes of formulating common underlying principles of navigation. The scientists have broken the known mechanisms into four levels, from simple to complex. The first is the sensorimotor toolbox, which includes vision, audition, olfaction, touch, magnetism, and proprioception. At the second level they put “spatial primitives,” animals that orient using simple representations and landmarks, terrain slope, compass headings, boundaries, posture, speed, or acceleration. At level three are more complex i
ntegrations of these tools to build spatial constructs, tools like an internal cognitive map. And at the fourth level they put spatial symbols: external maps, signage, and human language, essentially the ability to communicate spatial information. According to this idea, the simplest tools are fundamental—they appeared early in evolution and have persisted through the eons, and the more complex tools are synthesized from the early ones.
But conceptualizing animal navigation as a toolbox creates its own confounding questions. More often than not, animals once thought by scientists to use relatively elementary tools are discovered to have far more flexible and sophisticated tools at their disposal. Some animals seem to have all the tools, while others that would logically seem to require the most complicated tools make do with very simple ones. And some of the simplest tools in the box are ones we don’t understand at all. We have evidence that they exist, but we can’t see them and barely know how they work. For these reasons, the field of animal navigation today still contains some of the most fascinating biological puzzles in science. We have amassed a body of data based on tens of thousands of observations of animals navigating across the planet, yet we still grope to explain how they do it.
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One of the devices that an animal needs to navigate is a “clock”—an internal mechanism for measuring or keeping time. The daily mass migration of zooplankton in the world’s oceans requires them to know when dawn and dusk are approaching. It would seem this is a simple response to light stimuli, but deep-sea zooplankton, which live at depths below where light penetrates, also migrate in accordance with the length of day at different latitudes. Even slightly more complex migrations can demand multiple clocks. In their book Nature’s Compass: The Mystery of Animal Navigation, James Gould and Carol Grant Gould describe the “eerily consistent” migration of Bermuda fireworms, a bioluminescent marine species that emerges en masse once every lunar month in the summer or, more specifically, fifty-seven minutes after sunset on the third evening after the full moon. To pull it off, the Goulds hypothesize that the fireworms must have a 27.3-day lunar clock, a twenty-four-hour daily clock, and an interval timer in order to measure the fifty-seven minutes from sunset. Animals that complete annual migrations or multiyear migrations have to possess a yearly clock, one that is finely attuned to the lengths of days and nights and their changes across each season. In all, evolution seems to have produced annual clocks, lunar clocks, tidal clocks, circadian clocks, and, perhaps for those that migrate under cover of darkness, a sidereal clock—which measures the time it takes a star to appear to travel around the earth.
One of the first people to discover the use of clocks by animals for navigation was an amateur entomologist fascinated by desert ants. Felix Santschi was a Swiss physician who left his home in Lausanne in 1901 and moved to a remote city in Tunisia. Santschi described and named almost two thousand ant species in his lifetime and was intrigued by their behavior, particularly how the ants outside the ramparts of the city he lived in navigated the desert. At that time, as the German neuroethologist Rüdiger Wehner has written, some surmised that ants oriented by scent trails; they foraged in one direction and then followed the scent they had laid down back again. But the desert is an environment where wind and sand create an ever-changing landscape, blowing away scents and landmarks that ants might use for orientation.
Santschi was the first to notice that ants weren’t just following trails back and forth on their foraging trips, they were traveling in circuitous routes and then taking a direct route back. The ability to calculate a shortcut meant the ants were essentially doing trigonometry, calculating the spatial relationships among all the places they had visited and divining the straightest route home. Santschi knew this required a directional cue of some sort by which they could reliably orient themselves in space, and his guess was that ants were using a celestial compass, most likely the sun, by tracking its position at sunrise and throughout the day. To test this, he took a mirror to deflect the sunlight and observed that the ants changed their course back home by 180 degrees.
But the earth is not stationary, and the sun’s position in the sky changes. For it to be an accurate navigational aid, an animal must change its angle of orientation over the course of the day to maintain a constant direction. Thus, Santschi thought ants had to have an internal representation of time in addition to the sun in order to derive accurate directions. Later he even tried limiting the ants’ view of the sun entirely, and found they could still find their way based on even a small patch of sky. Subsequent biologists discovered that an ant’s ocelli, light-sensitive photoreceptor organs on the head, can read information from a blue sky even when the sun and landmarks are obscured, using the polarized pattern of light to orient the ant and help it find its way home. It is, the entomologist Hugh Dingle ventures, a kind of “preprogramed ‘hard-wired’ representation of a celestial map.”
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Honeybees can also use polarized light to find their way. They have been called the most elegant of nature’s navigators, embarking on up to five hundred trips a day, as far as five miles from their hives, in search of flowers and food. Like desert ants, they not only take circuitous, meandering routes in search of pollen but are always able to take the straightest route back home—a “beeline.” How they manage to calculate shortcuts has been the subject of entire books and countless research papers—even Aristotle puzzled over them. Their feats are even more impressive because bees embark on far-reaching rambles with what we would deem considerable impairments. Their brains weigh less than a milligram and contain fewer than one million neurons, and they are blind by human standards with merely 20/2000 vision.
The biologist James Gould at Princeton University has been studying bee navigation for decades. On its surface, beelining seems to require what is called path integration, dead reckoning, or inertial navigation; by keeping track of each stage of a journey, the insects can compute their location and the direction home. But as a young biologist, Gould found that no matter where he displaced bees within their foraging areas, they were always able to find new shortcuts, suggesting that they have a flexible memory or internal representation of space. In other words, bees are using a far more complex evolutionary tool, what is often called the cognitive map. Bees not only seem to have an internal representation of space but appear to possess the ability to communicate this “map” to other bees, a capacity that, according to the navigational toolbox idea, is assumed to be specific to the human species.
In the 1940s, the Austrian scientist Karl von Frisch observed that bees, after discovering a rich source of food on their foraging journeys, flew back to the hive and began waggling their bodies in a figure-eight pattern. There was a very specific grammar to this dance, particularly if the bees were returning from flights greater than fifty meters away. The bees moved their bodies along a vertical sheet of honeycomb, and it turned out that the angle at which they positioned themselves against this surface to waggle was the angle their hive mates should fly in relationship to the sun. Furthermore, the duration of the dance was proportional to the distance of the food from the hive. The bees were giving directions to their hive mates to follow but using their bodies to illustrate the journey. Some bees would keep up the dance for hours, or restart the dance the next day, or even after several months of freezing weather, and their accuracy never seemed to suffer.
As he describes in his 1950 book Bees, von Frisch also discovered that like ants, bees were orienting in space using the sun as a compass, which meant they were also using internal clocks: a twenty-four-hour internal clock and a seasonal calendar tracking the passage of time. As to how honeybees learn the movement of the sun and its coinciding times, studies show that the third week of a honeybee’s life is spent close to the hive, embarking on short flights, during which the bee learns the azimuth angles of the sun, its movement, and how to orient, before launching into long-distance foraging. In 2005 a team of German and British scientists led by Randolf Menzel describ
ed these early flights as a period in which young bees are forming an exploratory memory, perhaps the very cognitive map suggested by Gould. But they discovered that the map is far richer and more flexible than previously understood. In the journal Proceedings of the National Academy of Sciences (PNAS), the scientists reported how they took three different groups of bees and displaced them in the night, tracking their flight paths with a harmonic radar—transponder antennas that were attached to individual bees and that emitted a wavelength picked up by a receiver. The bees recognized familiar landmarks from different angles and created new courses from arbitrary locations.
Monarch butterflies, lizards, shrimp, lobsters, cuttlefish, crickets, and rainbow trout as well as numerous migratory birds have been proven to use polarized light as a “compass,” raising the question of whether this is a case of convergent evolution (a kind of coincidence of natural selection among independent organisms) or a shared ancient mechanism, present in the earliest species and carried through the eons.
While some animals navigate using the sun, others follow the stars. African ball-rolling dung beetles were known to navigate by the sun and moon, but in 2012 some scientists were puzzled by their ability to find their way even on moonless nights. They decided to release beetles with their dung balls in a walled space that limited their visual cues to the night sky and filmed their movements. It was clear that the beetles were orienting without the moon, meaning they must be using the stars to find their way. But how? The vast majority of stars, as the scientists pointed out, should be too dim for the beetles’ eyes to detect. By taking the beetles into a planetarium, they soon discovered that the insects relied on the bright light of the Milky Way to get home. Likewise, southern cricket frogs, Namibian desert spiders, and large yellow underwing moths have all been proven to orient by the stars. Several bird species, including indigo buntings, European pied flycatchers, and blackcaps, seem to orient by the North Star, using it as a rotational center to guide them through the night.
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