Every year, across the vast expanses of our planet, a remarkable and often unseen drama unfolds in the animal kingdom. From the tiniest insects to the largest mammals, numerous species embark on epic journeys, traversing thousands of miles in search of food, mating grounds, or warmer climates.
These migrations are feats of endurance and navigation that have fascinated scientists and nature lovers alike. They highlight the incredible adaptability and resilience of wildlife, often facing daunting challenges and predators along the way. The reasons behind these migrations are as varied as the creatures that undertake them, driven by an ancient instinct and the need to survive and thrive.
Related: 10 Bizarre Animal Races
10 Dragonflies (Globe Skimmer)
The Pantala flavescens, also known as the globe skimmer dragonfly, embarks on an extraordinary annual migration from India to Africa. It covers an impressive nonstop distance of 1,553 miles (2,500 kilometers) across the Indian Ocean to Somalia. This journey, astounding for an insect barely two inches (5 cm) long, has fascinated biologists for years.
Researchers at the Indian Institute of Technology in Kharagpur, West Bengal, are investigating how these dragonflies achieve such a feat. They developed a model to study the energetics of dragonfly flight, factoring in elements like lift, drag, wing-beating frequency, and the insect’s fuel storage. The research indicates that a globe skimmer can sustain 90 hours of steady flight at a speed of 15 feet per second (4.5 meters per second).
However, for the migration to be successful, more than sheer endurance is needed. The prevailing winds, particularly the Somali jet stream, are crucial. Favorable conditions for the crossing from India to Somalia occur after September, with the best chances for success in December. This aligns with the sightings of the dragonflies in Somalia during November and December.
The return journey to India is also aided by the Somali jet stream, which influences the Asian summer monsoon. The team discovered multiple routes that meet the necessary flight conditions, explaining why dragonflies don’t always follow the same path and occasionally end up in different parts of Asia.
This study emphasizes the significance of timing and environmental factors in the dragonflies’ migration. It also sparks questions about how climate change might impact these migratory patterns. However, several mysteries persist, such as how the dragonflies ascertain optimal wind conditions, their navigation to tiny islands en route, and the transmission of this knowledge across generations.[1]
9 Caribou
Caribou migration is a breathtaking natural phenomenon, marked by the animals’ movement across diverse terrains to meet their survival needs. These patterns differ between subspecies, influenced by food availability and predator evasion. Usually, caribou migrate north toward mountains in the fall and winter, returning to coastal fields in the spring and summer. For example, the Porcupine subspecies commences its migration on the Alaskan and Canadian coasts, forming large herds in the warmer months to escape bugs, then dividing into smaller groups as they head north in the fall.
Each herd has distinctive birthing fields, which differ by species. By late June or early July, they start their trip back south, seeking bug-free areas. Caribou migrations are consistent, often led by inherited herd leaders. To guard young ones from predators like wolves, grizzly bears, and golden eagles, caribou migrate in large groups, positioning the young and mothers near the center.
The exact mechanisms guiding caribou migration remain under study, but environmental and weather cues are believed to play a major role. These migrations are among the largest globally, with herds ranging from 50,000 to 500,000 individuals. The largest is the Barren-Ground caribou herd, primarily in Northwest Canada, with about 300,000 members. The Porcupine Herd in Alaska, with over 170,000 members, has the longest migration route worldwide, covering nearly 1,500 miles (2,415 kilometers).[2]
8 Elephant Seals
Northern elephant seals embark on a biannual journey into the North Pacific, known as a double migration. This migration allows them to forage and build up energy reserves, which are necessary for fasting during land-based activities that last two to four months. Interestingly, males and females hunt in different areas and prey on different species, potentially due to their unique dietary needs.
Some seals eat en route, while others don’t—a behavior that is currently being studied. During the two migrations, males cover at least 13,000 miles (21,000 kilometers) and females just over 11,100 miles (18,000 kilometers), spending 250 (males) and 300 (females) days at sea. Their migration is limited by the need to return to land for breeding and molting at two specific times each year. Females tend to travel further and for longer during their second migration after molting. However, overall, males travel a greater distance than females despite spending less time at sea.
Males and females exhibit different migratory patterns and diets. Males typically migrate north to northwest along the continental margin toward the nutrient-rich Gulf of Alaska, foraging at the bottom of the sea (benthic environment). In contrast, females usually migrate west-northwest and forage within the water column (pelagic environment).
These distinct foraging preferences are inferred from the correlation between dive depth and ocean depth. Even though males, due to their larger size, require more food, they spend less time foraging than females. This suggests that males may consume larger amounts of food and food types with higher caloric values. The areas above the continental shelf and within the Gulf of Alaska, where males typically forage, are known for their rich food sources.[3]
7 Bar-Tailed Godwits
The bar-tailed godwit, a marvel of the avian world, is celebrated for its extraordinary annual migration that commences in Alaska and concludes in New Zealand each fall. This epic journey, a nonstop flight that stretches over a mind-boggling 7,000 miles (11,265 kilometers), takes approximately eight days to complete. Throughout this grand voyage, these avian adventurers fly relentlessly over the expansive Pacific Ocean, never pausing for rest or retracing their path.
Nils Warnock, the Executive Director of Audubon Alaska, has devoted his time to studying the godwits by employing sophisticated satellite tags. His extensive research has unveiled that these birds are not merely ordinary migrants but extraordinary travelers that push the boundaries of endurance. One particularly impressive godwit, affectionately named E-7, astounded researchers by flying nonstop for an astonishing seven days, traversing a distance of 6,214 miles (10,000 kilometers) from New Zealand to the Yellow Sea. This region serves as the solitary stopover site between New Zealand and Alaska, making it an indispensable checkpoint on the godwits’ migratory path.
The bountiful tidal mudflats of the Yellow Sea, teeming with nourishment, are vital for the birds to replenish their energy reserves, gain weight, and fortify themselves for the grueling flights that lie ahead. However, these nourishing mudflats are now under threat. They are rapidly disappearing, an unfortunate circumstance that poses a significant threat to the godwits’ migration. This loss of habitat could disrupt their migratory patterns and pose a challenge to the future of this incredible species.[4]
6 Salmon
Salmon are renowned for their remarkable navigation skills, especially when returning to their birth streams. This navigational prowess relies heavily on their extraordinary senses rather than vision. From their natal freshwater environments to the vast expanses of the ocean, salmon imprint on the unique smells and chemical compositions of these habitats throughout their life stages. This sensory imprinting allows them to embark on expansive journeys across the North Pacific Ocean, only to return precisely to their birthplace.
While this homing instinct is inherited, the specific migration pattern is not. As they journey further from their home stream, their reliance on smell decreases due to the dilution of scent in the ocean waters. Fascinatingly, it has been discovered that salmon also imprint on the earth’s magnetic field when they first enter the ocean.
Salmon possess an acute ability to detect minor variations in this field, which aids them in pinpointing their location in the ocean. This process of geomagnetic homing is facilitated by the salmon’s lateral line, a sensory organ that picks up magnetic variations, vibrations, and electrical currents in water. Though the full extent of this sensory process remains a mystery, it’s thought that this internal compass not only informs them of their current location but also provides timely cues for their return journey.[5]
5 Great White Sharks
Like bears and sea lions that use fat and blubber to sustain themselves over long periods, great white sharks also need to store energy for their extensive travels. These sharks migrate annually over distances exceeding 2,500 miles (4,000 kilometers), moving between feeding and breeding grounds. However, they face the challenge of limited food availability in the vast Pacific Ocean.
Researchers from Stanford University and the Monterey Bay Aquarium conducted studies to understand how these sharks manage such long journeys without constant feeding. Due to the inherent danger in studying great white sharks closely, the researchers had to create safe methods to collect data. They observed a well-fed great white shark at the Monterey Bay Aquarium and noticed that as the shark gained mass, it also became more buoyant.
The key to their findings came from analyzing data from shark archival tags, focusing on a behavior known as “drift-diving.” This behavior involves sharks relaxing their fins and allowing currents and momentum to carry them forward. The data showed that migrating sharks gradually lose buoyancy over time. This loss of buoyancy was connected to the sharks’ use of stored oil in their livers, which can make up to a quarter of their body weight.
Before migration, sharks store oil, increasing their buoyancy. As they use this stored energy during their journey, they become less buoyant and start to sink more. This discovery not only provides insight into the sharks’ migration but also has implications for understanding the storage strategies of other marine animals and aiding conservation efforts.[6]
4 Humpback Whales
Humpback whales are known for their extensive migratory patterns, with a journey that begins in nutrient-rich, cold waters during spring to fall. In these seasons, they feed voraciously, accumulating a reserve of blubber. As early winter ushers in, they transition to travel to tropical waters for calving and mating. Remarkably, throughout this migration, their consumption drops significantly, and they rely mostly on their blubber reserves.
Their journey is no small feat, with a round trip spanning up to 10,000 miles (16,100 kilometers), a record only recently surpassed by a Grey Whale that covered almost 14,000 miles (22,530 kilometers). The migration process is methodical, taking between four and eight weeks, and follows a specific order. Mothers and calves are the pioneers, setting off first. They are followed by sub-adults, then adult males, and finally, the pregnant females who delay their departure to maximize feeding time.
A fascinating aspect of humpback whale migration is that they can be observed year-round in certain regions, such as British Columbia, Canada. This is due to variations in individual migration times. Furthermore, different groups of humpback whales have unique destinations. For example, those found in Southeast Alaska and Northern B.C. often migrate to Hawaii, while those from the Salish Sea predominantly set course for Mexico. Intriguingly, some whales are known to switch breeding grounds annually.
The journey is fraught with perils, particularly for the calves who become targets for Bigg’s killer whales. This threat of predation is one of the compelling reasons behind the humpback whales’ migration to warmer waters. Evidence of this danger is visible on many humpback whales off the coast of Mexico, who bear scars from killer whale attacks, suggesting that mothers often succeed in defending their calves.[7]
3 Wildebeest
The Great Wildebeest Migration is a spectacular natural event, renowned as one of the most sought-after experiences for wildlife and nature enthusiasts. This massive movement involves over a million animals, primarily wildebeest, along with zebra, topi, and other gazelle, traversing the Serengeti-Mara ecosystem in a constant, circular migration pattern.
The migration begins in the southern part of Tanzania’s Serengeti near the Ngorongoro Conservation Area, where the animals calve. They then journey in a clockwise direction through the Serengeti, heading toward the Masai Mara in Kenya, before returning to their starting point toward the end of the year.
The migration is a dramatic and dynamic event, marked by high-stakes encounters with predators and the birth of thousands of new calves, which replenish the herds and sustain the circle of life. The movement of the wildebeest is believed to be guided primarily by their response to the weather, particularly the rains and the growth of new grass.
The journey is fraught with danger, including attacks by predators like lions, leopards, cheetahs, hyenas, wild dogs, and crocodiles. The Great Migration is not only a spectacle of survival and endurance but also plays a crucial role in the ecosystem. Different groups of grazers consume grass at varying heights, which helps maintain the health of the grasslands.[8]
2 Monarch Butterflies
The migration of North America’s monarch butterfly is an extraordinary natural phenomenon. Unlike other butterflies, monarchs embark on a two-way migration similar to birds, as they cannot endure the cold winters of northern climates and migrate to warmer regions instead. Eastern North American monarchs overwinter in the Sierra Madre Mountains of Mexico, while their Western counterparts settle in California.
In Mexico, the butterflies roost in high-elevation oyamel fir forests, which offer an ideal microclimate for their winter survival. The forest’s temperature and humidity allow the monarchs to conserve energy without exhausting their fat reserves. Researchers speculate that the butterflies use various navigational aids, such as the earth’s magnetic pull and the sun’s position, to reach their wintering locations.
During their roost, monarchs cluster in large groups for warmth, with thousands sometimes congregating on a single tree. This clustering is vital for their survival in the cold months. Consequently, preserving the oyamel forests is crucial for the monarchs, prompting the Mexican government to establish the Monarch Butterfly Biosphere Reserve in 1986.
Monarchs can cover 50-100 miles (80-160 kilometers) a day, with the longest recorded journey being 265 miles (426 kilometers) in one day. During their southward migration, Eastern North American monarchs utilize several flyways, which eventually converge in Central Texas. Remarkably, these butterflies instinctively navigate to their wintering sites despite never having been there before.[9]
1 Arctic Terns
The Arctic tern, a small bird known for its epic journey, covers a round-trip distance of about 18,641 miles (30,000 kilometers) each year. This annual trek from the Arctic Circle to the Antarctic Circle and back is among Earth’s longest animal migrations. Arctic terns hatch during the Arctic summer. To avoid the harsh, dark Arctic winter, they fly south, following the summer season, to the Antarctic Circle.
Their migratory route is not a straight line, however, making the journey even longer than the direct distance between the two circles. This migration, driven by their quest for the summer sun, is a result of the earth’s tilt, causing different hemispheres to experience varying seasons.
Arctic terns migrate in colonies. Before migration, the colony observes a period of silence, a behavior known as “dread.” Then, they collectively leave their nests. This migration is a survival strategy that helps them avoid the harsh Arctic winter and find food more readily. Evolved to be lightweight, these birds favor gliding, using ocean breezes to traverse long distances without much energy expenditure. They can even sleep and eat while in flight.
Tracking has revealed that Arctic terns often fly thousands of miles off track to benefit from favorable weather and food sources. While most return to their original nesting grounds, some have been found off-course in areas like South Africa and Australia. Despite their small size, Arctic terns are not endangered due to their remote breeding grounds in the high Arctic, which are challenging for predators to find.[10]