6 Seriously Impressive Animal Migrations

Summary

This SciShow episode explores the incredible journeys of various animals during migration. From the Grant's caribou's 4,000 km land migration to the Arctic tern's 15,000 km flight, the show highlights six remarkable cases. It also covers zooplankton's daily vertical migration, the bar-headed goose's high-altitude flight over the Himalayas, Emperor penguins' winter trek in Antarctica, and the symbiotic migration of golden jellyfish in Palau for sunlight and nutrients. The episode emphasizes the diversity and complexity of animal migration strategies.

Takeaways

• 🌍 Animals migrate for various reasons such as avoiding cold, giving birth, or finding food.
• 🦌 The Grant's caribou holds the record for the longest land migration, covering over 4,000 kilometers.
• 🐦 The Arctic tern has the longest migration distance of any animal, traveling from the Arctic to the Antarctic.
• 🌊 Zooplankton may hold records for both the smallest and most numerous migrating animals, participating in daily vertical migrations.
• 🐦 The bar-headed goose is listed in the Guinness World Records as the 'highest migrant', flying over 7,000 meters above ground.
• 🐧 Emperor penguins undertake impressive journeys across Antarctica in winter, sometimes without eating for weeks.
• 🌞 Golden jellyfish in Palau migrate daily to maximize sunlight exposure for their symbiotic algae.
• 🔬 Scientific thinking and understanding of natural laws help scientists uncover the mysteries of animal migrations.
• 🌐 Migration patterns vary widely among different species and are influenced by factors like food availability and environmental conditions.
• 🎓 Learning about scientific thinking can help anyone better understand the natural world and the behaviors of its inhabitants.

Q & A

What is the significance of animal migration?

Animal migration is significant as it allows them to avoid harsh weather conditions, find food, give birth in safer environments, and avoid predators.

Which animal holds the world record for the longest migration over land?

The Grant's caribou holds the world record for the longest migration over land, covering more than 4,000 kilometers.

What are some reasons caribou migrate?

Caribou migrate to reach calving grounds near the coast, find high-quality vegetation, and avoid biting insects like mosquitos.

How does the Arctic tern's migration compare to the caribou's?

The Arctic tern's migration is longer than the caribou's, with a straight-line distance of about 15,000 kilometers and a meandering route that can be up to five times farther.

What hypothesis explains the Arctic tern's long migration route?

One hypothesis suggests that the terns migrate so far south to follow the bright summer sunlight, which helps them see their aquatic prey more clearly and take advantage of calmer summer breezes.

What is unique about the zooplankton's migration?

Zooplankton may hold two world records for migration: being the smallest migrating animals and the most numerous. They perform daily diel vertical migrations, moving downwards into darker waters during the day and upwards towards the surface at night.

Why do zooplankton migrate vertically?

Zooplankton migrate vertically to avoid predators that hunt visually by staying in darker, deeper waters during the day and to find food at night by moving to the surface.

What is special about the bar-headed goose's migration?

The bar-headed goose is listed as the 'highest migrant' by Guinness World Records, as it can fly over 7,000 meters above the ground to cross the Himalayas during its migration.

How do Emperor penguins' migration habits differ from other birds?

Emperor penguins do not migrate across continents and oceans but instead travel across Antarctica in the winter to reach their breeding grounds.

What challenges do Emperor penguins face during their migration?

During their migration, Emperor penguins face extreme cold, must stop eating for weeks, and the males have to survive off of fat stores while caring for the eggs until they hatch.

How do golden jellyfish in Palau's tropical lake benefit from their migration?

Golden jellyfish migrate to maximize sunlight exposure for the algae within their tissues, which undergoes photosynthesis and provides energy for the jellyfish. They also migrate vertically at night to access necessary nutrients and avoid predators.

What role does scientific thinking play in understanding animal migrations?

Scientific thinking allows scientists to understand animal migrations by applying knowledge of natural laws and interpreting evidence within that framework.

Outlines

00:00

🐾 Animal Migrations: The Journeys of Caribou and Arctic Tern

This paragraph discusses the incredible journeys that animals undertake during migration. It highlights the Grant's caribou, which holds the world record for the longest land migration, traveling over 4,000 kilometers across various terrains to reach their calving grounds and find better vegetation while avoiding insects. The Arctic tern is mentioned as having the longest migration distance ever recorded, flying from the Arctic to the Antarctic, covering up to 75,000 kilometers. The tern's migration pattern is believed to help them follow the summer sunlight for better prey visibility and take advantage of calmer summer breezes. Their route is also influenced by the availability of food, as they follow winds along food-rich ocean regions.

05:01

🐧 Emperor Penguins and Golden Jellyfish: Adaptations and Symbiotic Migrations

The second paragraph focuses on Emperor penguins and their unique migration patterns. Unlike other birds, they don't migrate across continents but instead travel across Antarctica during winter, leading to extreme conditions where males may stop eating for weeks. The paragraph also covers the bar-headed goose, which is known for flying at extremely high altitudes over the Himalayas, possibly as an adaptation developed over millions of years. The golden jellyfish of Palau is highlighted for its symbiotic relationship with algae, where the jellyfish migrates to maximize sunlight exposure for the algae, which in turn provides energy for the jellyfish. This migration is not solely for the jellyfish's benefit but also for its algal partner, and it also helps them avoid predators like anemones.

Keywords

💡Migration

Migration refers to the seasonal movement of animals from one region to another, typically in response to changes in weather, food availability, or breeding needs. In the video, migration is the central theme, with various species highlighted for their incredible journeys, such as caribou traveling over 4,000 kilometers and Arctic terns covering vast distances between the Arctic and Antarctic.

💡Caribou

Caribou, also known as reindeer, are large mammals mentioned in the script for their remarkable land migration. They undertake journeys of over 4,000 kilometers, exemplifying the lengths animals will go to reach calving grounds and find better food sources, as well as to escape harsh conditions like biting insects.

💡Arctic Tern

The Arctic tern is a small seabird highlighted for having the longest migration distance recorded. It migrates from the Arctic to the Antarctic, covering up to 15,000 kilometers, and potentially much more with its meandering route. This behavior is hypothesized to help them follow the summer sunlight for better hunting and take advantage of calmer breezes.

💡Zooplankton

Zooplankton are tiny aquatic organisms that play a significant role in marine ecosystems. The script mentions their daily diel vertical migration, where they move to deeper, darker waters during the day to avoid visual predators and ascend towards the surface at night to feed. This migration is crucial for their survival and is an example of how even the smallest creatures undertake impressive journeys.

💡Bar-headed Goose

The bar-headed goose is noted in the script for being the 'highest migrant,' capable of flying at altitudes over 7,000 meters to cross the Himalayas. This extreme altitude adaptation is crucial for their survival during migration, showcasing the incredible adaptations animals develop to overcome environmental challenges.

💡Emperor Penguin

Emperor penguins are highlighted for their impressive non-flying migration across Antarctica to reach their breeding grounds. The script describes how males fast for weeks while incubating eggs, illustrating the extreme measures some animals take for reproduction and survival.

💡Golden Jellyfish

Golden jellyfish from a tropical lake in Palau are mentioned for their daily horizontal migration to maximize sunlight exposure for the algae living in symbiosis within their bodies. This migration is not just for the jellyfish's benefit but also for their algal partners, demonstrating the complex relationships in nature.

💡Diel Vertical Migration

Diel vertical migration is a pattern of movement in which organisms move vertically in the water column at different times of the day. The script uses zooplankton as an example, explaining how they descend during the day to avoid predators and rise at night to feed, illustrating the strategic behaviors of small organisms in response to their environment.

💡Symbiosis

Symbiosis is a close and long-term interaction between two different species. In the context of the golden jellyfish, it refers to their relationship with the photosynthetic algae (zooxanthellae) living within their tissues. The jellyfish provide sunlight for the algae, and in return, the algae provide energy for the jellyfish, exemplifying a mutualistic symbiosis.

💡Adaptation

Adaptation in biology refers to the process by which an organism becomes better suited to its environment. The script mentions various adaptations, such as the bar-headed goose's ability to fly at high altitudes and the special proteins in Emperor penguins' blood that help them absorb oxygen efficiently. These adaptations are crucial for their survival during migration.

💡Brilliant.org

Brilliant.org is mentioned as a sponsor of the video series and as a platform offering courses in scientific thinking and other subjects. The script encourages viewers to explore scientific thinking to better understand natural phenomena like animal migration, suggesting that such courses can deepen one's comprehension of the world.

Highlights

Millions of animals undertake incredible journeys each year for various reasons such as avoiding cold, giving birth, or finding food.

Grant's caribou holds the world record for the longest land migration, traveling over 4,000 kilometers annually.

Caribou migrate to reach calving grounds, find high-quality vegetation, and avoid biting insects like mosquitoes.

The Arctic tern has the longest migration distance of any animal, traveling from the Arctic to the Antarctic circles.

Arctic terns may travel up to five times the direct distance between their breeding and wintering grounds due to a meandering route.

Zooplankton potentially holds two migration records: the smallest migrating animal and the most numerous one.

Zooplankton exhibits diel vertical migration, moving to deeper waters during the day and towards the surface at night.

Bar-headed geese are listed in the Guinness World Records as the 'highest migrant,' flying over 7,000 meters above ground.

Bar-headed geese fly at high altitudes over the Himalayas, evolving special adaptations to deal with low oxygen levels.

Emperor penguins undertake impressive journeys across Antarctica in winter, sometimes going without food for weeks.

Golden jellyfish in Palau migrate horizontally to maximize sunlight for their symbiotic algae, and vertically at night for nutrients.

Animals migrate not only for their own survival but also for their symbiotic partners, as seen with the golden jellyfish and zooxanthellae.

The diversity of animal migration is vast, with many organisms having unique migration stories not covered in the transcript.

Scientific thinking, with its strong understanding of natural laws, is crucial for studying and understanding animal migrations.

Brilliant.org offers a Scientific Thinking course that can help individuals learn more about understanding the world through science.

The Scientific Thinking course from Brilliant is accessible, requiring no prerequisite courses and is packed with puzzles.

By signing up through the provided link, the first 200 people can get a 20% discount on an annual Premium subscription to Brilliant.

Transcripts

Thanks to Brilliant for supporting this whole week of SciShow!

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[♪ INTRO]

Every year, millions of animals undertake amazing journeys.

They migrate to avoid the cold, to give birth, or to find food,

and to do it, they can travel hundreds of kilometers over all kinds of terrain.

Now, you’ve probably already heard about things like geese heading south for the winter

or salmon swimming from oceans to rivers to lay eggs.

But these feats only represent a tiny fraction of how animals migrate.

There are some seriously impressive stories out there, and they come from all kinds of creatures;

some big and familiar, and others so small, you can barely see them.

Here are six of our favorites.

Caribou are found in North America, Europe, Asia, and Greenland.

And if you’re looking at this picture and thinking, “That’s a reindeer!”, you’re right!

They’re the same thing, although the name changes

depending on where you live and whether the animal is domesticated.

Regardless of its name, though, some subspecies of caribou are serious migrators.

In fact, one of them, called the Grant’s caribou, holds the world record for longest migration over land.

Each year, they take a journey that can cover more than 4,000 kilometers,

which is about the width of the entire United States.

And this adventure can span many types of terrain, taking them through ice fields or over mountains.

Like some animals, caribou do this partly to reach their calving grounds near the coast,

where they’ve given birth for generations.

But they also do it to find more high-quality vegetation

and even avoid pesky mosquitos and other biting insects.

In fact, when the insects are at their worst, these caribou actually travel the fastest,

and who can blame them?

Even though the caribou migrates the farthest over land,

its journey is nothing compared to the Arctic tern’s.

The Arctic tern is a small seabird,

and it holds the record for having the longest migration distance ever recorded.

When winter arrives in the Northern Hemisphere, the birds fly from the Arctic circle

in the northernmost part of the globe, towards the Antarctic circle in the southernmost part.

Now, that’s already a long distance, about 15,000 kilometers,

but the birds can travel up to five times farther than that by taking a meandering route.

That long trek sounds exhausting, but it might be a smart decision for the birds.

One hypothesis suggests that traveling so far south helps the terns follow the bright summer sunlight.

That would allow them to see their aquatic prey more clearly,

and they could take advantage of the calmer summer breezes.

As for why they don’t just fly straight to the Antarctic?

Well, that also seems to be about food.

In a 2009 study published in the Proceedings of the National Academy of Sciences,

researchers attached lightweight geolocators to terns and tracked their migration routes.

They found that, along the way, the terns traveled over food-rich regions of the ocean,

flying along with the winds to help them keep up their energy.

In other words, the meandering route allows them to get in some good meals

and not run themselves into the ground.

Or fly themselves into the ocean. You get it.

It makes sense that birds and mammals would migrate in search of more favorable conditions.

But this next story takes place in oceans and lakes, with a much smaller creature: zooplankton.

These are tiny, aquatic organisms about as thick as a dime,

and they usually drift along with the currents since they’re weak swimmers.

But when they have to move, they move.

In fact, zooplankton could possibly hold two world records for migration:

the record for the smallest migrating animal, and the most numerous one.

Every day, up to billions of these animals participate in what’s called diel vertical migration.

During the day, they migrate downwards into darker waters,

but at night, they go upwards, towards the surface.

Some evidence for this comes from studies of zooplankton in their natural habitats,

like a 2000 paper published in a German journal about freshwater biology.

In the study, scientists found that allowing artificial light to shine on a lake at night

significantly reduced the number of one type of zooplankton hanging out there.

And that makes sense, since that light mimicked the sunlight normally found during the day.

Other studies have found similar results with other types of zooplankton, too.

Some researchers suggest the animals do this to avoid predators that hunt with their sense of sight.

By sticking to the darker, deeper waters during the day,

there’s a smaller chance they’ll be spotted and eaten.

But they can’t avoid their foes like this forever: After all, there’s not a lot of food in those deep waters.

So at night, once the bright sunlight goes away, they might migrate to the surface to get their meals.

Next up, here’s another world-record holder: the bar-headed goose.

If you live in the US, you’re probably familiar with Canada geese,

which hang out in warmer climates during the winter.

But the bar-headed goose in Central Asia is arguably way cooler.

They’re listed with Guinness World Records as the “highest migrant.”

To enter and exit their breeding grounds in Tibet,

these birds can fly more than 7,000 meters above the ground.

That’s only about 2,000 meters lower than where commercial jets hang out!

They don’t just do it for funsies, though.

They have to reach these altitudes because their migration path takes them over the Himalayas.

One of the tallest mountain ranges in the world!

At this point, it’s not super clear why they take such an extreme route, though.

Scientists suggest it could give them an advantage over other animals,

or it could be because they’ve been flying this way for millions of years.

So maybe they had to adjust as the Himalayas got taller.

In any case, what scientists do know is that geese have evolved special adaptations

to deal with the low oxygen levels on their flights.

For example, they have a special type of protein in their blood

that lets them quickly absorb oxygen at high altitudes.

They also have more small blood vessels around their cells,

which improves how oxygen gets transported to their muscles.

In a 2019 paper, researchers even reported that the birds lower their metabolisms

and change the way they move their wings to conserve as much oxygen as possible.

So scientists will keep investigating why they migrate at such serious heights,

but one way or another, they’re pretty great at it.

Now, Emperor penguins aren’t exactly obscure.

They’re featured in everything from primetime documentaries to children’s movies,

because, well, have you seen them? They’re great.

These birds live on the frigid, Antarctic side of the world, and you can often pick

them out by the yellow feathers around their necks.

Unlike some other birds, they don’t migrate across continents and oceans,

but their journeys are no less impressive.

In their quest to reach their breeding grounds, they travel across Antarctica in the winter;

a decision so extreme that it ultimately forces some of them to stop eating for weeks.

During the three months of summer, Emperor penguins live by the ocean,

where they can hunt and feed on prey like fish and squid.

But as soon as the waters begin to freeze and the ice thickens up,

they start to march inward, toward their breeding grounds.

These breeding sites are called rookeries, and they can be found at the base of icy cliffs.

The cliffs provide some shelter from the weather, but once the penguins arrive,

not all of them stay there for the whole season.

After the females lay their eggs, they head back to the sea to eat,

leaving the males to care for the eggs until they hatch.

And unfortunately, that means the poor males get no fish.

Instead, they have to survive off of fat stores for the better part of the winter.

Somehow, though, it’s a strategy that works for them.

The birds even take advantage of these cliffs for as long as possible.

Usually, they’re there for months, because once their chicks hatch, they have to wait

for their waterproof feathers to grow before they can make their first trip to the ocean.

Our final example brings us far from the Antarctic,

to a tropical lake on the remote Pacific island of Palau.

In that lake live millions of squishy, umbrella-shaped creatures called golden jellyfish.

Among other things, they’re really fond of the sun.

The tissues in the jellyfishes’ bodies contain algae called zooxanthellae,

and the two organisms have a seemingly happy partnership.

The jellyfish make sure that the algae receive ample sunlight so they can undergo photosynthesis.

And byproducts of the algae’s photosynthesis provide energy for the jellyfish.

This symbiotic relationship is what drives the jellyfish’s daily migration.

As the sun crawls across the sky, the jellyfish migrate horizontally

to maximize the amount of sunlight their algae receive.

And at night, the jellyfish migrate downward vertically

so that the algae can receive other necessary nutrients.

So mostly, these animals aren’t migrating for themselves, but for their partners.

Which is kind of cute.

Of course, it does have one last advantage for the jellyfish:

By migrating away from the lakeshore, these animals can avoid their main enemies, the anemones.

As with many creatures, not all golden jellyfish migration is the same.

Their movements, routes, and even speed may vary depending on where they live.

But the basic strategy is still pretty cool.

These six stories show how amazing animal migrations can be,

but somehow, they still haven’t scratched the surface of all the diversity here.

From reptiles to insects, there are plenty of organisms we couldn’t cover,

each with adventures of their own.

It just goes to show that something that might feel ordinary is more fascinating than you’d think.

You just have to look closely.

One the many reasons scientists have been able to learn about these migrations

is because they’re good at what you might call scientific thinking.

They have a strong understanding of the laws of nature

and how their evidence fits within that framework.

So scientific thinking is a great way to understand the world around you.

And if you want to learn more about how to do it,

you can check out the Scientific Thinking course from Brilliant!

It’s packed with puzzles and requires no prerequisite courses,

so if you’ve never tried Brilliant before, this might be a good fit.

And when you’re done, you can also check out one of their many other

science, engineering, computer science, or math courses.

To sign up or to learn more, head over to Brilliant.org/SciShow.

If you’re one of the first 200 people to sign up at that link,

you’ll get 20% off of an annual Premium subscription.

[♪ OUTRO]