(and no, it's not because they're willing to stop and ask for directions)⤒🔗

Since the advent of global positioning satellites, or at least since their availability for civilians, scientists have found many uses for these devices. One of the more in­teresting applications is to track animals. Of obvious popular appeal are programs such as "fish with chips."

This is a multimillion dollar Census of Marine Life project. In conjunction with this program, thousands of marine ani­mals in the Pacific Ocean, including many fish, have been fitted with electronic sur­veillance tags. As of 2005, midpoint in a ten-year program, some interesting results have been recorded. Thus far about 1,800 sharks, tuna and turtles have been fitted with transmitting devices which relay in­formation to a satellite when the animal surfaces. By this means, a bluefin tuna was tracked as it crossed the Pacific Ocean three times in 600 days. This fish swam 40,000 kilometers (km) with an average of 66 km/day.

More dramatic still were the exploits of Nicole, a 3.5 meter (m) long great white shark. This specimen swam 11,000 km from South Africa to Australia and back within three months. Nicole thus averaged 122 km/day. She swam in a straight line, never less than 5km/hr and 60% of the time she stayed within one meter of the surface. It is obvious she knew where she was going.

Scientists have been astonished to dis­cover how far these and many other ani­mals migrate. Another interesting study involved young fingerling salmon emerg­ing from 16 river systems on the Pacific coast of North America. The tags on several thousand of these fish were scanned as they passed over special receivers placed on the ocean floor from Washington State up to Alaska. This study revealed that the young salmon follow precise migration paths which vary depending upon their river of origin.

The results of these tracking studies intensify the question, long pondered, as to how animals navigate long precise routes through the oceans or skies. As our tools for study become ever more sophisticated, our insights might be expected to increase too. This may be, but the more famous cases still abound in unanswered questions.

Freshwater eels←⤒🔗

Eels are long snake-like fish which can grow up to 3 m long. While some might consider such creatures ugly, many in Eu­rope and North America consider them very tasty snacks.

However, there was one longstanding mystery concerning the freshwater eels of eastern North America and Europe. Why were no young eels ever observed? Did they spring fully grown from their parents, like the mythical goddess Minerva who was imagined to have sprung mature and fully clothed from Jupiter's brain?

A Danish biologist solved the problem early in the twentieth century. Johannes Schmidt discovered that freshwater eels from both sides of the Atlantic spawn in a remote region of the Atlantic Ocean east of the Bahamas Islands. As is typical when one mystery is solved, this answer raised many new questions. How and why do all these eels navigate so far?

The Sargasso Sea, a region of the At­lantic Ocean where water currents slowly move in a gigantic gyre (whirlpool), is roughly the size of Australia. Its existence is a by-product of the Gulf Stream which car­ries warm water north along the eastern coast of North America and then eastward toward Europe, and the North Equatorial Current which carries cold water south to­wards Africa and then west towards the Caribbean. It so happens that this sluggish whirlpool region of the Atlantic is very rich in mineral nutrients. Sargassum, a distinc­tive floating brown seaweed, grows so thickly there that the sea surface some­times looks more like a meadow than like open water. Naturally this region is a won­derful habitat for sea life and there the eels go to mate.

In the fall, eels which are about ten years old, undergo physical and physiolog­ical changes. They stop eating as their stomachs shrink, and their reproductive or­gans expand. These mature specimens then move from their preferred freshwater habi­tats down streams to rivers, and from rivers to the sea. They proceed from far inland along the Atlantic coast from Mexico up to Labrador, from Greenland's coast and Ice­land, from the British Isles, from Scandi­navia and from lands bordering the Mediterranean and Black Seas. As these eels converge on the Sargasso Sea, they show no specific preference to mate with specimens from their part of the world. Each female then lays up to twenty mil­lion eggs. These hatch into thin, flat, al­most transparent creatures about one half cm long. As they move north in the Gulf Stream, those which mature first, appar­ently stop off in the fresh waters of North America. Others may take longer to ma­ture, up to two or three years and these drift towards Europe. The American and European populations look different, but biologists think that genetically they may be almost identical.

It is apparent that we know some of the story concerning eels but there are ob­viously many blanks yet to fill. What causes the eels to migrate to a common area in the open ocean? Why do they not spawn closer to their feeding grounds? Drifting towards coastal areas is obviously easy enough, but how do the eels navigate their way back to the Sargasso Sea? There obviously is more to freshwater eels than a tasty snack.

Sea turtles←⤒🔗

Most of the seven species of sea tur­tle can be found throughout the world's tropical and subtropical seas. Despite this wide range, local populations exhibit very specific nesting site preferences and some­times even a specific preference in feed­ing site as well. This scarcely seems remarkable until we realize that the nest­ing and feeding sites may be thousands of kilometers apart. After decades of ecologi­cal studies, scientists still have only a poor understanding of the wonders of sea turtle navigation.

Green turtles are a rugged, long-lived species (up to 70 years). As is typical with sea turtles, the female lays her eggs at night in the sand of a wide beach along the seashore. She digs a pit, and lays as many as one hundred eggs. After covering the eggs, the mother then retreats into the sea. Several weeks later, all the eggs hatch at the same time. The hatchlings emerge from the sand and head straight for the ocean. Once immersed, they swim straight out, farther and farther from land with its multitude of avian, crustacean and hu­man predators. Only about one in one thousand hatchlings survives long enough to mature.

Once in the open sea, young turtles ap­parently set out for the feeding grounds. Green turtles hatched on beaches of Costa Rica later turn up in Spain, Chile and Brazil. Then, once mature, females return to the very same beaches from which they hatched fifteen to thirty years previously. Tagging programs with young turtles have never revealed an adult female nesting on a beach other than the one from which she emerged. How do these turtles, out at sea, navigate towards the appropriate beach?

One of the more remote destinations on earth is Ascension Island. Situated in the mid South Atlantic Ocean, this island of 88 square kilometers lies about 1100 kilo­meters northwest of Saint Helena, itself an island famous for its remote location. (Napoleon Bonaparte spent his last days on Saint Helena, a site chosen as his prison because its distance from everywhere made escape impossible). However Ascension Is­land is even more isolated than Saint He­lena. Nevertheless green turtles, feeding in shallow waters along the Brazilian coast, and others in similar habitats near Gabon (Africa), swim due east or west (respec­tively) to nest on the beaches of Ascension Island. The journey from Africa to the is­land is 2500 km and from Brazil to the is­land is 2250 km. It is like finding a needle in a haystack. Nevertheless adult female tur­tles make the journey once every three to four years. Moreover they do not eat at all during the entire eight month return trip.

Amazing skills in navigation are not unique to green sea turtles. Studies on the largest turtle of all, the leatherback, reveal some interesting details too. Unlike the green turtle, the leatherback forages for food in the deep ocean so they are less tied to specific feeding grounds. Nevertheless there are only a few dozen places in the world where these turtles lay eggs. Of these, only four beaches attract large num­bers of nesting leatherbacks. One of these four beaches is Playa Grande Beach on the west coast of Costa Rica. Tagging studies have revealed that these turtles travel 2500 km west from Costa Rica toward the Gala­pagos Islands and beyond into deeper wa­ters. They confine this travel to a narrow corridor up to 480 km wide. The females return to Playa Grande to lay eggs up to ten times per season. The females of an­other leatherback population, which feeds on jellyfish in the waters off Canada's Nova Scotia coast, later proceed to beaches within the Caribbean Sea in order to nest.

Studies on turtle navigation have re­vealed that young hatchlings react posi­tively to wave direction, the earth's magnetic field, moonlight, and perhaps chemical gradients. Nobody has, however, established precisely how adult turtles navigate thousands of kilometers in the open ocean, or even why they do so. Even if turtles are able to orient themselves in a specific direction, how do they locate the particular beach from which they hatched ­so many years previously and on which they spent so short a time?

Monarch butterflies←⤒🔗

One of the most amazing examples of navigation is that of the monarch butterfly. During the spring, these insects leave tiny stands of trees in Mexico where they spent the winter. They fly northeast to destina­tions throughout eastern North America. Then in the fall, several generations later, these butterflies head back to the very same stands of trees from which their great-great grandparents had emerged the pre­vious spring.

Several questions naturally arise. It may be that day length triggers the in­stinct to fly southwest in the fall, but how do these tiny brains identify the appropriate direction? Recent laboratory studies have shown that adult butterflies emerge at dawn from the chrysalis. This time is ap­parently internalized within each insect's 24 hour physiological clock. (Your own physiological clock tells you, for example, when it is time to sleep and time to eat.)

It is the insect's awareness of passing time which allows these butterflies to nav­igate with the sun as their reference point. As the sun moves across the sky, the but­terflies automatically adjust their orienta­tion to the sun according to the time of day and thus they maintain a constant south­west direction. If any butterflies are artifi­cially caused to emerge from the chrysalis at a different point in the day, they cannot navigate according to the sun's position and consequently they get lost.

Imagine a navigating system that au­tomatically adjusts for time of day! This is a fancy computer to cram into a very small insect brain. Obviously the whole system was designed to function in a sophisti­cated manner while using on a few sim­ple cues. In the spring after over-wintering, these very same butterflies will fly toward the northwest.

Arctic birds←⤒🔗

In certain instances a much simpler navigating system than that of the butter­flies may suit the needs of an animal. This situation applies to arctic birds on their an­nual migration south. Navigation appar­ently is most difficult near the poles since many useful parameters, like magnetic field, all converge.

During the late summer of 2005, sci­entists carried out a study of arctic bird nav­igation. As flocks of birds passed over the Bering Strait between Alaska and Siberia, scientists briefly tracked them by radar. From hundreds of such tracks, the travel trajectories (direction) could be calculated. Already the scientists had calculated the various routes that birds would follow if they were using one or other navigational cues. If the birds were navigating by means of a magnetic compass, for example, they would proceed towards the northeast (not an ideal direction). If they used the sun as their reference point, adjusting their calcu­lations according to time of day, they would proceed towards the east. However if they followed the sun without adjusting direc­tion for time of day, they would proceed in a southeast direction. This was indeed the path these birds appeared to follow.

The end result of this strategy is that their route then traces an arc, part of a great circle. Such a route is by definition the shortest distance connecting two points on the globe. For people relying on technology, a great arc requires continu­ous changes in compass direction. Navi­gating by compass (magnetic field) is longer but much easier. Obviously, how­ever, one expends less energy on a shorter route. In the case of arctic birds, lacking complex computer programs, they nevertheless manage to follow a sophisticated path out of the arctic. Scientists cannot re­frain from asking how these birds learned such a navigational strategy.

Conclusion←⤒🔗

There is no doubt that recent tracking studies have revealed exciting details about animal navigation. In addition, physiologi­cal studies continue to give us glimpses into methods which these creatures use to plot their routes. But none of these environ­mental cues would be any help at all with­out senses designed to perceive them, and brains to interpret the data correctly, and to act upon it. Secular scientists may even­tually describe the tracking mechanisms ever so precisely, but they will never be able to tell us why or how these remark­able designs were conferred on these crea­tures Christians know.