Some creatures stick to a small territory all their lives, but others move with the seasons to survive. Whether for food or just to avoid the lethal cold, some of these animals make journeys that take multiple generations to complete. Check out the...
1. Moseying Monarch ButterfliesMigrating to avoid the worst of the winter weather isn't uncommon, but Monarch butterflies take things to the extreme. Come autumn these insects leave their feeding grounds in America and Canada and fly towards the mountains of central Mexico, using air currents to help power the journey. Once there, they cluster beneath the insulating foliage of fir trees to endure the winter.
The strange part is the return journey - these butterflies will never make it home. Instead, they fly some of the way back before laying eggs on milkweed plants and producing a new generation... who continue the trek home.
This process repeats four or five times until the insects reach the feeding grounds again, with each "traveling" generation living for only five to seven weeks. The butterflies that make the 3,000 mile trip to Mexico and last the winter have a much longer lifespan.
Researchers believe that this long migration may help cull parasites that infest the Monarch feeding grounds - the absence of butterflies means no hosts for the locals!
Scientists as far back as the 4th century BCE have been trying to unravel the life cycle and migratory patterns of the European eel, and details are still being discovered. A recent project electronically tagged the eels, revealing that the migration to the Sargasso Sea takes over a year - the spawn (known as glass eels) drift back to the coasts of Europe on the ocean currents.
3. Caribou ConvoysCaribou (reindeer) are highly migrational animals - herds keep separate summer and winter ranges, moving between them twice a year. It's not uncommon for an individual to travel 2,000 miles on one of these journeys... and one particular caribou was recorded moving 2,700 miles in a single trip.
The caribou instinctively move to calving grounds to foal – these areas have fairly few predators and decent grazing. Each new calf can travel ten miles a day just two days after birth and soon joins up with the herd. This capability is important as the caribou form up into massive moving aggregations during mosquito season in an attempt to avoid some of the swarming blood-drinkers.
The caribou migrations have a significant impact on indigenous culture. When they move through Onion Portage (so called due to the large numbers of wild onions that grow in the area) hunters follow, picking off animals for meat and fur. Archaeological evidence suggests that this has been going on for over 10,000 years.
Each winter, the crabs move en-mass from the forest to the coast to spawn. Local authorities spend months preparing barricades, bridges and even funnels to guide the crustaceans safely from the forest to the shore without risking the roads.
5. Drifting DragonfliesDragonflies may be powerful fliers and well-adapted predators, but they still require fresh water to reproduce. For this reason, their annual arrival in the Maldives (coral atolls with almost no surface fresh water) is a bit of a puzzle.
Based on matching genetics, biologists suggest that these dragonflies may be using the islands as a rest stop in a flight from India to Africa and back again.
The journey is pretty dangerous - the nomadic beasts having to evade the attention of Nile crocodiles in the rivers and other large predators on the plains. Even if they avoid the predators, steep river banks can lead to panic and drowning. The sheer number of corpses provides a significant boost to the African ecosystem - presumably, the abundance of fresh grazing after the rains outweighs the risks!
- Moseying Monarch Butterflies
- Enterprising Eels
- Caribou Convoys
- Clattering Red Crabs
- Drifting Dragonflies
- Salmon Sojourners
- Globe-Trotting Terns
- Wandering Wildebeest
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| Monarch butterflies huddle in Mexico overwinter... (Alex Guillaume) |
1. Moseying Monarch ButterfliesMigrating to avoid the worst of the winter weather isn't uncommon, but Monarch butterflies take things to the extreme. Come autumn these insects leave their feeding grounds in America and Canada and fly towards the mountains of central Mexico, using air currents to help power the journey. Once there, they cluster beneath the insulating foliage of fir trees to endure the winter.
The strange part is the return journey - these butterflies will never make it home. Instead, they fly some of the way back before laying eggs on milkweed plants and producing a new generation... who continue the trek home.
This process repeats four or five times until the insects reach the feeding grounds again, with each "traveling" generation living for only five to seven weeks. The butterflies that make the 3,000 mile trip to Mexico and last the winter have a much longer lifespan.
Researchers believe that this long migration may help cull parasites that infest the Monarch feeding grounds - the absence of butterflies means no hosts for the locals!
2. Enterprising Eels
River-dwelling European eels take a massive and poorly understood trip to the Sargasso Sea when it's time to spawn. The creatures can travel as far as 10,000km to reach this floating patch of seaweed and detritus - a massive marine journey by almost any standard.Scientists as far back as the 4th century BCE have been trying to unravel the life cycle and migratory patterns of the European eel, and details are still being discovered. A recent project electronically tagged the eels, revealing that the migration to the Sargasso Sea takes over a year - the spawn (known as glass eels) drift back to the coasts of Europe on the ocean currents.
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| Caribou make massive journeys twice a year... (Anonymous) |
3. Caribou ConvoysCaribou (reindeer) are highly migrational animals - herds keep separate summer and winter ranges, moving between them twice a year. It's not uncommon for an individual to travel 2,000 miles on one of these journeys... and one particular caribou was recorded moving 2,700 miles in a single trip.
The caribou instinctively move to calving grounds to foal – these areas have fairly few predators and decent grazing. Each new calf can travel ten miles a day just two days after birth and soon joins up with the herd. This capability is important as the caribou form up into massive moving aggregations during mosquito season in an attempt to avoid some of the swarming blood-drinkers.
The caribou migrations have a significant impact on indigenous culture. When they move through Onion Portage (so called due to the large numbers of wild onions that grow in the area) hunters follow, picking off animals for meat and fur. Archaeological evidence suggests that this has been going on for over 10,000 years.
4. Clattering Red Crabs
Whilst the distances traveled by the red crabs of Christmas Island are dwarfed by some of the others on this list, few match them for raw spectacle. Imagine a tide of advancing scarlet crustaceans scuttling their way to the beach with no regard for the roads of "civilized" man - or personal safety.Each winter, the crabs move en-mass from the forest to the coast to spawn. Local authorities spend months preparing barricades, bridges and even funnels to guide the crustaceans safely from the forest to the shore without risking the roads.
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| A fine site for a dragonfly holiday... (Pexels) |
5. Drifting DragonfliesDragonflies may be powerful fliers and well-adapted predators, but they still require fresh water to reproduce. For this reason, their annual arrival in the Maldives (coral atolls with almost no surface fresh water) is a bit of a puzzle.
Based on matching genetics, biologists suggest that these dragonflies may be using the islands as a rest stop in a flight from India to Africa and back again.
If this is the case, the insects are making a round trip of over 14,000km and probably using favorable winds to do it. Short-lived freshwater monsoon pools on the Maldives represent an opportunity for the roving insects to reproduce en-route!
6. Salmon Sojourners
The Atlantic salmon spends its early life in freshwater rivers adjacent to the North Atlantic Ocean and the Baltic Sea. The young fish spend a few years maturing in the rivers before heading out to sea, a fairly simple trip that follows the flowing water. Once in the open ocean, they spend a further one to four years growing in size before making the return journey to spawn.The trip back is a great deal more strenuous. When the salmon returns to the rivers, it must battle the swift-flowing water or even "leap" up waterfalls to get to the place where it started life. Even if it avoids predators and successfully mates, the salmon will probably die of exhaustion before it can return to the sea - it doesn't feed during the trip inland.
7. Globe-Trotting TernsWeighing in at around 100 grams and known for a disproportionate level of aggression towards anyone disturbing it, the Arctic tern makes a return trip between the Arctic and the Antarctic each year.
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| Wildebeest migrations help support the African ecosystem... (Helena Pfisterer) |
7. Globe-Trotting TernsWeighing in at around 100 grams and known for a disproportionate level of aggression towards anyone disturbing it, the Arctic tern makes a return trip between the Arctic and the Antarctic each year.
The tern uses the Arctic as a breeding ground during the summer, then has a second summer in the Antarctic. This massive cyclic journey can mean a single bird ends up travelling 59,000 miles in a year... for context, the distance between the Earth and the Moon is around 238,855 miles.
8. Wandering Wildebeest
Though wildebeest can reach nearly two and a half meters in length and weight 270 pounds, they're surprisingly mobile. They make their home on the Serengeti of Africa, grazing on the vegetation that grows in the savanna conditions... but each year, they perform a massive looping migration, moving northwest at the end of the rainy season to find better sources of food.The journey is pretty dangerous - the nomadic beasts having to evade the attention of Nile crocodiles in the rivers and other large predators on the plains. Even if they avoid the predators, steep river banks can lead to panic and drowning. The sheer number of corpses provides a significant boost to the African ecosystem - presumably, the abundance of fresh grazing after the rains outweighs the risks!
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