One of the amazing facts about life on our planet is the way living things fill every niche of the environment. As science extends our knowledge of Earth’s remote regions, we find massive amounts of life with incredible diversity. We find the largest animal population on the Earth in biomass, the volume of the Earth occupied, and numbers of individuals in water deeper than sunlight can reach. The ocean depths make up 90% of Earth’s living space, and we now understand that living there are more than a million species that science has not named or described. Furthermore, they are part of the greatest daily migration on Earth.
Every day, ten billion tons of animals known as zooplankton move upward from as far as 3,000 feet below the surface. The zooplankton include copepods, salps, krill, and fish larvae. At only 1,000 feet down, the water is 20 degrees Fahrenheit colder than at the surface, and the pressure is 30 times as great. For a tiny fish larva, making a 1000-foot journey in about an hour would be like a human swimmer going 50 miles in that amount of time. These animals begin their ascent at sunset and stay near the surface until sunrise when they descend back to the cold dark below.
The purpose of this greatest daily migration on Earth is to eat and avoid being eaten. These zooplankton animals feed on phytoplankton, the microscopic aquatic plants that live in the top few hundred feet of water. Fish and squid feed on the zooplankton, which find protection at the great ocean depths. The first hint of this massive migration occurred in World War II when ships and submarines used sonar to sweep the ocean for enemy subs. They discovered that the seafloor seemed to be moving up and down, creating a deep “scattering layer” that reflected sonar signals. Now we have research tools to explore this layer, which turns out to be alive.
Science is just now beginning to understand the importance of the greatest daily migration on Earth. This huge mass of animal life, their excrement, and their remains sequester carbon in the very deep waters, making them rich in nutrients. Winds along the shores of continents push the surface water from the continental edges out into the open ocean. Their exit causes water to come up from ocean depths to the surface along the continent’s edges, bringing nutrients with it.
Our understanding of this mass migration is helping us to understand the carbon cycle, climate change, and many ecological issues. This greatest daily migration on Earth is a part of God’s creation. It reminds us of Proverbs 8:28-29, which says that Wisdom was there, “…when He established the clouds above and fixed securely the fountains of the deep, when He gave the sea its boundary so the waters would not overstep His command, and when He marked out the foundations of the earth” (NIV).
It’s a bird that isn’t great at flying and is awkward at walking on land, but it’s very skilled at diving. The common loon (Gavia immer), also known as the great northern diver, is an aquatic bird that somewhat resembles a large duck or small goose. Since flying isn’t their strong point, why do loons migrate?
Most birds have hollow bones to reduce their weight for flying. The fact that a loon’s bones are not hollow adds weight to facilitate diving but makes flying more of a challenge. Loons can dive as deep as 200 feet (60 meters) and stay underwater for three minutes. Because of their dense bones, they sit lower in the water than ducks or geese when they swim. The loons’ legs, located near the rear of their bodies, facilitate quick diving but make walking more difficult.
Loons are well-designed for catching fish and well-suited for life in the ocean, where they spend their flightless winters. When spring comes, the loons molt, shedding their gray feathers and growing black ones. They gain stiff wing feathers and begin exercising to build strength for the migration journey. After a couple of months of preparation, they are ready to fly hundreds of miles north to freshwater lakes, where they spend the summer.
Why should loons leave the oceans where they have an abundant food supply? Just think that they wouldn’t have to go through the changes necessary to fly to the northern lakes. They could also avoid the dangers involved in making the migration. They wouldn’t need the complex navigation methods they use to return to the same lakes where they originated. Why do loons migrate? Why not do what many northerners do when they retire and just enjoy life along the warm and sunny ocean shores?
The answer seems to be more beneficial to other living creatures than to the loons. Their departure from the ocean relieves pressure on fish populations in coastal marine areas. More than that, it helps to control fish populations in northern freshwater lakes. Loons return to the north to benefit the northern ecosystems. These birds are well-designed to fill a niche in the ecosystem that other life forms can’t fully meet.
So even though loons are not the best at flying and even less adapted for walking, they have what is needed to fill a niche in the ecosystem. Why do loons migrate? The loon’s migration may benefit other living creatures more than itself. How could natural selection explain this? According to the survival of the fittest, shouldn’t these birds survive and thrive doing their own thing rather than benefiting others? We don’t think natural selection fully explains the design of loons and their lifestyle. We suggest that the common loon is a testimony to the Creator’s wisdom of design in the life system we see all around us.
In a December 2021 National Geographic article, Peter Gwin portrays the wildebeest as the “Unlikely King of the Serengeti.” That title suggests that the animal and its role are too complex for us to comprehend. In the case of the wildebeest, both their physical design and their incredible mass migrations of more than 1.3 million animals have drawn the attention of scientists.
The wildebeest is an animal that seems to have been fashioned from the parts of other animals. They have a head like a warthog, a neck that looks like an American buffalo, stripes like a zebra, and the tail of a giraffe. Wildebeest are members of the antelope family, but they have small horns, shaggy beards, big humps, and small legs. Their three-week birthing period in January allows them to produce 500,000 calves at the rate of about 24,000 per day. Despite their clumsy appearance, a wildebeest can run 50 miles (80 km) per hour and annually migrate 1,750 miles (2,816 km). They are the largest animals to engage in such a long migratory journey.
In their migration, wildebeest cross rivers in massive numbers. Tourists come to watch these crossings where crocodiles feed on many of the animals. The king of the Serengeti is also a food source for lions, hyenas, cheetahs, and leopards. New studies of the wildebeest and the Serengeti show the complex design of these animals and their environment.
Wildebeest migration follows the rain. As they travel through Kenya and Tanzania, wildebeest can sense where it is raining, and they follow the precipitation. By eating the new grass that the rain produces, wildebeest prevent the grass from growing tall enough for wildfires to develop. The lack of fires allows forests to grow, thus allowing more insects for birds to eat and more leaves to feed the herbivores. That sustains the elephant, giraffe, zebra populations.
It’s easy to see why the king of the Serengeti is not the lion but the wildebeest. It is a keystone species that, by its design, feeds many life forms and, by mass migrations, allows a stable ecology in the Serengeti. This is an example of God’s design of an animal that is only now being understood and appreciated. Everywhere we look, we see that a wonder-working hand has gone before.
References: The National Geographic issue for December of 2021 is one of the most interesting issues that popular magazine has produced. It is connected to a Disney program that will be streamed starting on December 8. The program titled “Welcome to Earth” will be hosted by actor Will Smith and feature many different animals and plants, including the wildebeest.
One of the most amazing things we see in the natural world is the ability of some living things to make incredible migrations. In the past, we have described the monarch butterfly’s migrations from wintering areas in Mexico to northern parts of the United States covering a round trip of about 10,000 kilometers. However, we see that painted lady butterflies out-migrate monarchs.
Scientists have studied how the monarchs navigate such incredible distances with formidable obstacles in their way. Biologists have proposed a variety of models as to how these fragile butterflies could acquire such an ability. However, in the case of the monarchs, the journey is not made by a single butterfly but by a succession of generations.
Science News for July 21, 2018 (page 4) told about a study of another butterfly with an amazing migration. It has the scientific name Vanessa cardui and is commonly known as the painted lady butterfly. These butterflies live in Southern Europe and migrate to Africa in the fall–a distance of 12,000 km. That’s 2000 kilometers farther than the monarchs, and the journey involves crossing the Sahara Desert. As with the monarchs, scientists had believed that the migration involved several generations. New techniques allowed researchers to put markers on the painted ladies when they were caterpillars. We now know that at least some of the butterflies make this incredible journey in one lifetime.
One of the most interesting examples of design in living things is the ability that various forms of life have to migrate great distances for a wide variety of reasons. Sea turtles have an uncanny ability to return to the same beaches over and over to lay their eggs. Whales can travel long distances when they are ready to calve, giving their offspring a greater chance of survival. Migrations can be critical to animals or plants other than the animal making the migration. Sometimes the migration is critical to an environmental ecosystem. The salmon migration in Alaska, for example, is critical to the entire area sustaining plant life and a wide variety of animal life.
When insect migrations are studied, the question of how they make the migrations and why becomes even more complicated. Monarch butterflies make migrations of great lengths even though their life expectancy is too short for any single butterfly to make the entire migration. The champion of insect migrations is the globe skimmer dragonfly (Pantala flavescens). This insect has wide wings that look very delicate, but those wings can carry it for thousands of miles seeking wet seasons when it can reproduce. Migration has spread this insect’s DNA worldwide to every continent except Antarctica. Globe skimmers can fly for hours without landing and have been seen as high as 20,000 feet (6,200 m) in the Himalayas. They are sometimes called wandering gliders because they can glide on thermals in a way similar to birds. They seem to prefer moist winds, and they don’t stop for bad weather.
It is easy for humans to minimize the design that is needed for life to exist on Earth. How do you feed massive numbers of birds, especially in the spring when winter has taken away most of their food sources, and their food needs are maximized as they lay eggs and feed baby birds? In the past scientists have shrugged their shoulders and imagined that there are food sources we don’t recognize that fill this gap until the summer season generates sufficient seeds and insects to sustain the growing populations. Similar problems exist for many other animals like bats that depend on insects for their nutritional needs.
In the April 2017 issue of Scientific American (page 84), there is an interesting report about previously unknown migrations of insects. We have known about monarch butterflies for some time, but this study by British researchers shows that migrations of insects are massive. Over southern Britain alone there are 3.3 trillion insects migrating. That is an average of 3200 tons of bugs moving through the skies over Britain every year. The study also reports that similar patterns have been observed in Texas, India, and China.
The complexity of this migration is astounding. Insects don’t live long enough for one bug to complete the migration. Researchers found that in some cases six generations were involved to complete a migration. The insects do not just get randomly blown about. They travel in a well-programmed pattern taking advantage of wind direction and speed. The elevation at which they fly to get the strongest support for their journey is carefully chosen. For a number of reasons, spring migrations are different from fall migrations.
Over the years we have presented data on some amazing migrations. We have had several discussions about the Arctic tern and how it makes its incredible 12,000-mile journey. Research has shown that the Arctic tern uses multiple cues including magnetism, sight, smell, and even sound. We have also talked about whales, salmon, and sea turtles and the way they benefit multiple ecosystems by their migrations. Now we have a new migration that has just been discovered and is equivalent to 20,000 flying reindeer. It’s migrating insects.
According to the study, 2-5 million migrating insects fly over the United Kingdom each year. The study is reported in the December 23, 2016, issue of Science by a team headed by Jason Chapman. Tracking these arthropods involves the use of special radar designed to detect insects. The team estimates that the total biomass of these arthropods is 3200 tons which is 7.7 times more than the biomass of the songbirds in the same area. These are tiny creatures with some of them weighing less than 10 milligrams.
Chapman notes that these arthropods are not just accidentally caught up in the wind. Some of them climb to the top of a plant to launch their flight. Some stand on tiptoe and put out silk until the wind catches them and carries them away. The animals only launch when the wind is to the north from May to June, and in August and September, they launch when the wind blows to the south. Chapman concludes “these arthropods must have some kind of built-in compass plus a preferred direction and the genetics that change that preference as they or their offspring make the return migration.“