Meet the animals who really do take the long way home.
Crossing Continents – The Arctic Fox.
Arctic Foxes are tough little animals that thrive in temperatures as low as -50C. They may only weigh 7.5kg and have a head-to-tail body length barely over 100cm but it appears that these animals are a lot tougher than we previously thought. In 2018, a young female Arctic Fox began an incredible journey that see her travel all the way from Norway all the way to Canada in just 76 days.
Her story began in July 2017 when researchers from the Norwegian Polar Institute fitted 50 Arctic Foxes with radio collars. These collars transmitted the animals’ position each day for a three-hour period, enabling scientists to record the fox’s patterns of movement as well as how they used the rapidly retreating Arctic sea ice in their day-to-day lives.
Approximately one year after the radio collars were fitted, the scientists noticed that one particular female was beginning to stray from her home of Spitsbergen, the largest island in Norway’s Svalbard Archipelago. This was the start of an amazing Arctic expedition that would end with her finding a new home, over 2,737 miles (4,400Km) on the Canadian island of Ellesmere.
“We first did not believe it was true,” said Eva Fuglei, a member of the research team who watched the journey unfold from her computer screen. In fact, the journey the fox took was so long that the researchers initially questioned whether the fox’s collar could have been removed and was now transmitting location data on board a boat: “but no, there are no boats that go so far up in the ice. So, we just had to keep up with what the fox did,” Fuglei said.
Whilst the distance that this tiny animal travelled is remarkable, this journey becomes even more outstanding when you understand that her expedition took less than three months to complete. On her tiny legs, she ran (on average) 29 miles a day and on one particularly arduous day, she hurried across an incredible 96 miles of sea ice!
“This is, to our knowledge, the fastest movement rate ever recorded for this species” said the researchers, who added that this is the first time they have observed an animal migrating between not just different Arctic continents, but between entire ecosystems.
Shortly after reaching her new Canadian home on Ellesmere, the radio collar stopping transmitting data and her location has remained unknown to the researchers since. The most likely scenario is that she has settled down in the area to feed on the native lemming population. Unfortunately, this journey may be one that no other Arctic Fox will be able to undertake in the future.
Sea ice is vitally important to the local wildlife, allowing them to find food and safely shelter in the extreme Arctic conditions; however, sea ice across the region is retreating, melting away earlier and freezing over later each year. Norway’s Climate and Environment Minister, Ola Elvestuen said, “This is another example of how important sea ice is to wildlife in the Arctic. The warming in the north is frighteningly fast. We must cut emissions quickly to prevent the sea ice from disappearing all summer.”
This Arctic Fox’s remarkable journey from Europe to North America stunned everyone, from the researchers tracking her to local politicians. From the extreme distances covered, to the time taken to complete the journey, this expedition across the polar expanse demonstrates the incredible level of endurance and durability that Arctic Foxes possess, as well as the importance of sea ice.
I’ll See You There – The Northern Elephant Seal.
Weighing up to three tonnes and sporting one of the strangest noses on the planet, the Northern Elephant Seal is a fascinating marine mammal. Whilst their physical appearance is amazing, the journey that these animals embark upon each year is equally intriguing: 13,000 miles (21,000Km) from the breeding grounds of Mexico and California, all the way to the Gulf of Alaska.
Whilst this may not be the longest migration discussed in this article, what is interesting here is that the male and females take separate routes on their journeys along the North American coastline. The males will swim along the continental shelf, whereas females will travel via the open ocean. In fact, after setting off from the breeding grounds, mating pairs will only see each other again at their final Alaskan destination.
The reason why they take alternate paths is simple: they like different foods. Males prefer bottom-dwelling fish, rays and small sharks which tend to be found along the shelf, whereas females favour squids as their delicacy of choice, meaning they must travel further into the open ocean and away from the shelf.
Additionally, throughout the Northern Elephant Seals’ journey to the waters of Alaska, they will dive to remarkable depths. In order to catch their elusive prey, seals will regularly swim to depths between 300 and 800 metres (1,000 – 2,600ft), holding their breath for up to one hour at a time. Moreover, researchers have used special dive technology to record some Northern Elephant Seals diving to incredible depths in excess of 1,200 metres (4,000ft). To put that into perspective, that’s deeper than most military submarines are able to dive to!
A journey longer than a lifetime – The Monarch Butterfly.
When thinking about extreme animal journeys, insects do not naturally come to mind; however, not many species invest as heavily in their migrations as the Monarch Butterfly. Their annual journey from Mexico to Canada is so long that the majority of individuals never even see their home, with generations being routinely sacrificed so the group can move closer to their collective destination.
Every autumn, millions of Monarch Butterflies leave their winter homestead in southern Mexico and travel in excess of 3,000 miles to their summer breeding grounds of Canada. This is a vast distance to travel for such a small animal; however, this journey becomes even more remarkable when you consider their average life expectancy. The entire life cycle of the Monarch Butterfly only lasts between five and seven weeks, meaning that their northward journey takes as many as five generations to complete.
Incredibly, whilst it may take more than four generations to complete the entire journey, just one ‘super generation’ of butterflies is needed for their return to Mexico. This ‘super generation’ of butterflies ride the air currents all the way back down to their winter home in the same amount of time it takes up to five generations to travel north.
Whilst the distance of Monarch Butterfly migration may be less than those of other animals reported here, the commitment to reaching their destination from multiple generations is remarkable. For these animals, the journey is so vast that multiple generations are born, grow up and perish before they even come close to their true homes.
Pole to Pole – The Arctic Tern.
The Arctic Tern is a tiny bird, only weighing around 113 grams but despite their size, they make the longest migration for any animal on the planet. Every year, they embark on an incredible journey that takes them from pole to pole, a round trip covering over 40,000 miles.
Zigzagging their way from the Arctic, down the coastlines of Europe and Africa, they eventually end up in Antarctica just as the summer begins. In fact, the Arctic Tern is all about the summertime, enjoying two summers every year thanks to their travels across both hemispheres; this means that they see more daylight than any other species on Earth.
The pole to pole expedition that these birds make each year racks them up approximately 44,000 frequent flier miles (71,000Km); however, it’s the durability of these small animals that is truly amazing. As they live up to 30 years, the Arctic Tern may migrate more than 1.5 million miles (2.4 million Km) in their lifetime; that’s equal to three trips to the moon and back!
There and Back Again – The Great White Shark.
We have now discussed several examples of animals migrating great distances to specific locations; however, not all travelling animals have a destination in mind. In 2004, ‘Nicole’ the Great White Shark (named after the Australian actress Nicole Kidman) swam a whopping 6,900 miles (11,100Km) in just nine months, from South Africa to Australia and back again.
Nicole’s story began in November 2003 when a team of scientists from the Marine and Coastal Management Department of South Africa and The White Shark Trust attached a satellite tag to her dorsal fin allowing them to accurately track her movements through the water. Whilst the majority of the other sharks that were tagged stayed fairly close to the tag-site or made their way up the South African coastline, Nicole proceeded to swim into the open ocean.
Just three months after leaving South Africa, her tag detached and floated to the ocean’s surface just south of the Exmouth Gulf in Western Australia, revealing the amazing journey that Nicole had undertaken. In addition to the near-3,500 miles that she covered, the data uncovered that she had dived to depths of up to 3,215ft, a new record for Great White Sharks. Remarkably, the tag also revealed that she spent most of the journey swimming along the water’s surface, suggesting that sharks may actually use the stars for navigation when in the open ocean.
Whilst the researchers were stunned by the journey Nicole had undertaken, it appears that she wasn’t too fond of the Australian waters as in August 2004, approximately nine months after being tagged she resurfaced, back again in Gansbaai, South Africa. This incredible 6,900-mile swim took her just nine months to complete and has revealed more about the behaviour of Great White Sharks than the scientists could have ever hoped for.
The Longest Trek – The Grant’s Caribou.
Whilst individual animals can travel vast distances by themselves, mass migrations present a different set of challenges, requiring a large group of animals to understand where they are going and why they are going there together. For terrestrial animals, no other mass migrating species tops the Porcupine Caribou of North America.
Many species of Caribou travel extreme distances from their respective breeding grounds to their winter ranges; however, the Porcupine Caribou, a subspecies of reindeer also known as Grant’s Caribou go the extra mile and then some. Whilst their annual migrations along well-trodden tracks can reach upwards of 1,500 miles, the 2002 migration broke all records.
That year, a herd that numbered more than 230,000 individuals travelled approximately 2,982 miles (4,800Km) from Canada’s northern Yukon territory all the way across mountain ranges and valleys alike to Alaska’s coastline and eventually to the Beaufort Sea. Not only was this fantastic expedition across the frozen north the furthest for any terrestrial mammal, but it was also the most extreme for any land-based animal on the planet.
Voyaging the Pacific – The Humpback Whale.
Out of all the mammals on the planet, no species migrates further than the Humpback Whale. Whilst the average journey totals just over 3,100 miles (5,000Km), there are numerous stories of individual Humpback’s going above and beyond this figure.
In 2007, scientists documented a group of seven individuals including a mother-calf pair, travelling an astonishing 5,000 miles (8,300Km) from Costa Rica to Antarctica. It is not just distance that makes the Humpbacks’ migrations extraordinary, it’s the pace: scientists have recorded one individual taking just 36 days to swim all the way from Alaska to Hawaii.
In 2006, 400 scientists from 10 countries launched the SPLASH research project which uses identification photos and satellite imaging technology to record the movement patterns of whales. The researchers even documented the incredible journey of one intrepid individual who undertook an epic voyage from Ogasawara Island, south of the Japanese mainland, all the way to Vancouver Island in Canada – an astonishing 9,300-mile (15,000Km) swim.
Whilst most Humpback Whales travel vast distances each year between feeding and breeding waters, individuals also vary with regards to the time of year when they set off on these migrations. They can be seen all year round on the western coastline of North America; however, some whales don’t leave their northern waters as late as January or February and as such, they can overlap with individuals already returning from the breeding waters.
Smallest Mass, Biggest Moves – Zooplankton.
Whilst we have discussed incredible journeys, from individuals travelling vast distances to the groups of animals who undertake great annual migrations, the award for largest migration on the planet, in terms of biomass, goes to one of the smallest creatures in the oceans…Zooplankton.
Zooplankton are incredibly small animals, only 0.008cm in length and weighing around 0.00051g; however, they do indeed constitute the largest migration on Earth. Each day, the zooplankton migrate vertically between depths of 200 and 1000m in the water column, numbering so many that they do indeed constitute the largest synchronized movement of biomass on Earth.
The zooplankton engage in what is known as the Diel Vertical Migration, which is the movement of organisms through different layers of the water column based on the abundance of sunlight. The zooplankton move up to near the surface of the water in order to photosynthesise and then sink back into the depths for safety.
From the Arctic Fox to Humpback Whales and Zooplankton, animals of all shapes and sizes undertake remarkable journeys in search of food. This article has discussed a range of amazing migrations; however, there is (technically) one species that, ironically, surpasses all others. In terms of both the distance recorded by individuals (collectively) and overall biomass, no other species comes close to that of…human commuters.
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