The Great Escape: Following the Epic Journeys of Sea Turtles

Think about packing for a holiday, except that your destination is thousands of miles away and you’ll have to swim the whole time. Sounds exhausting, right? This isn’t a holiday for sea turtles, it’s just life. These ancient mariners undertake some of the most epic migrations on Earth, every year, a survival journey that has evolved over millions of years.

So, what motivates these extraordinary creatures to swim across entire oceans? It’s all about one of life’s most fundamental necessities: where to eat, grow and make babies. This guide explains the "who, what, when, where and why's" of total sea turtle migration.

Why Do They Migrate? The Grand Purpose

Sea turtles migrate mainly to swim from their foraging areas (where they feed) to their nesting beaches (where they breed). Foraging grounds are a turtle’s equivalent of a personal buffet and where they find their favorite foods. Depending on the species, that might be jellyfish or sponges, or crabs and seaweed.

 

 

 

 

 

 

 

 

But these feeding grounds are often located a long way from the warm, sandy beaches that are just right for incubating eggs. A sea turtle’s life can be separated into several stages, and each stage is likely to occur in a different location.

• Hatchlings: Once there’s a whole bunch of little hatchlings wiggling, it’s like a foot comes down on champagne glasses and corks and out they pop!  Torrenting toward the sea. They travel on ocean currents in their “lost years,” an early life stage when the fish are seldom spotted, moving with the sargassum seaweed and feeding on small organisms.
  
• Juveniles: As they develop, they change locations, in parts of the coast such as estuaries and coral reefs, where they mature.
  
• Adults: When you reach adulthood, you’re up for the big trek. The most celebrated migration is made by adult females, which return to the beach where they were born to lay their eggs. This amazing navigational achievement boggles the mind.
  
  

The Amazing GPS: How Do They Do It?

This is one of the biggest mysteries and most exciting areas of sea turtle research. How can a turtle, with a brain the size of a ping-pong ball, swim thousands of miles and find a specific beach? Scientists believe they use a combination of incredible natural senses.

• Magnetic Navigation: Imagine the Earth is one big magnet. Scientists have discovered that sea turtles have an internal magnetic compass. Dozens of different places on Earth have a distinctive magnetic “signature” — a sort of cosmic fingerprint. It can go about its business, guided by this magnetic map, having all the navigational cues that we derive from a map and a compass.
  
  
• Sun and Stars: Turtles, like ancient mariners, may also use the sun during the day and the stars at night to orient themselves.
  
  
• Olfaction (Smell): It is believed that, when close to shore, baby turtles can smell chemical clues from their home beach, which guide them toward the actual site.
  
  

Meet the Travelers: Different Species, Different Journeys

Every species of sea turtle has its own migratory style.

• Green Sea Turtle: These herbivores are known for some of the longest migrations. One famous population travels over 1,400 miles from Brazil to Ascension Island in the middle of the Atlantic Ocean to nest. That's farther than the distance between New York and Miami!
  
  
• Loggerhead Sea Turtle: Found worldwide. These round trips can be trans-oceanic, from nesting beaches in Japan to feeding areas near Baja California, Mexico.
  
  
• Leatherback Sea Turtle: The ultimate record holders of migration. Leatherbacks are the biggest turtles, and they undertake the longest migration of any vertebrate on record. One of the tagged leatherbacks swam more than 12,000 miles in just the course of a year, a vivid reminder of how far and fast they can travel. They are remarkable because they can thermoregulate, which means they can travel to cooler, more northerly waters in search of their preferred food: jellyfish.
  
  

The Perils of the Journey

While these migrations are a beautiful dance of life, they are also incredibly dangerous. Sea turtles face countless threats on their epic voyages.

• Plastic Pollution: Mistaking plastic bags as jellyfish is a big issue when turtles end up ingesting plastic it can cause the turtle’s digestive system to become blocked ultimately resulting in the turtle starved to death. 
  
  
• Fishing Gear: Getting caught in fishing nets and lines poses another major danger.
  
  
• Habitat Loss: While nests are safe on isolated beaches, turtles’ habitat is being destroyed as sand dunes are being removed to build more hotels and more tourists are flocking to the country’s coast. That is why it is so crucial to preserve these important habitats.
  
  
• Climate Change: Rising sea levels and shifting ocean currents can disrupt their navigational cues and nesting sites. Warmer sand temperatures also can affect the sex of hatchlings, as temperature decides the sex of the babies (warmer sand produces more females). This might cause extreme off-balance of population.
  
  

Fascinating Facts to Impress Your Friends

• "Magnetic Imprinting": The theory that turtles are born with a unique magnetic map of their birthplace is called magnetic imprinting. It's like their birth certificate is a set of magnetic coordinates.
  
  
• The "Lost Years": For decades, scientists had no idea what happened to hatchlings after they left the beach. We now know they spend their early years floating in ocean currents, but it's still one of the least understood phases of their lives.
  
  
• Super Evolved Lungs: Sea turtles can hold their breath for an incredibly long time, some for several hours. This allows them to dive deep and rest on the seafloor during their long journeys.
• They're Older Than Dinosaurs!: The first sea turtles appeared on Earth over 110 million years ago, during the time of the dinosaurs. They have literally been doing this migration thing for a very, very long time.

 

Why It All Matters

Sea turtle migration is more than a cool party trick of biology. It is a crucial aspect of the ecosystem of the ocean. They assist in the preservation of healthy coral reefs and seagrass beds, which then provide a habitat for numerous other marine animals. Protecting them is tantamount to protecting whole marine ecosystems.

So next time you see a photograph of a sea turtle remember the amazing journey it has traveled. It’s a totem of resilience, a navigation savant and a living piece of Earth’s geologic history. These wondrous travels are a tribute to the wild, beautiful world we still have and a call-to-action to defend it.