Did you know that every monkey in South America is related to monkeys from Africa? Scientists figured this out by studying their DNA. But here’s the big question: how did monkeys get from Africa to South America when the continents are so far apart? Surprisingly, most scientists think they floated across the ocean on a natural raft!
When we say “raft,” we don’t mean a boat that monkeys built. Instead, imagine a big bunch of driftwood, plants, and vines that broke off from the land and floated away. This idea might sound a bit crazy at first. Think about all the things that would need to happen for this to work:
The chances of all these things happening are super small. But scientists haven’t found any other explanations. Millions of years ago, there were no land bridges between Africa and South America, so monkeys couldn’t just walk across. Fossils show that these monkeys weren’t good swimmers either, so they couldn’t swim across the ocean. If they couldn’t walk, swim, or fly, floating was the only option left.
There are a few reasons why this rafting idea might not be as impossible as it seems. First, the ocean currents back then were really strong and moved from east to west. This means a raft could float from Africa to South America in just a few weeks. Second, there were times when the ocean was calm, making it easier for a raft to survive the journey. Third, in tropical areas, it rained a lot, so the monkeys would have had water and maybe even food from the plants on the raft.
Most importantly, if you have enough time, even things that seem super unlikely can happen. Imagine if a storm that could send a raft into the ocean happened once every two thousand years. Over millions of years, there would be thousands of chances for such a journey to start, and only one successful trip was needed for monkeys to make it to South America.
This kind of natural rafting might have happened with other animals too. Scientists think that lemurs floated 400 miles from Africa to Madagascar, and reptiles and rats traveled about 600 miles from South America to the Galapagos Islands. In 1995, scientists even saw a natural raft carry 15 green iguanas over 100 miles across the Caribbean to the island of Anguilla. The world is big and time is long, so even things that seem impossible can happen more often than we might think.
Imagine you are a monkey trying to cross the ocean. Use materials like sticks, leaves, and string to build a model of a natural raft. Test its buoyancy in a small pool or basin. Discuss with your classmates what challenges your raft might face on a journey across the ocean.
Using a world map, trace the possible route that monkeys might have taken from Africa to South America. Consider the ocean currents and discuss how they could have helped or hindered the journey. Present your findings to the class.
Explore how scientists use DNA to trace the origins of species. Research and create a simple presentation on how DNA evidence supports the theory of monkeys rafting from Africa to South America. Share your presentation with the class.
Participate in a simulation game where you must make decisions to help a group of monkeys survive on a raft. Consider factors like food, water, and weather. Reflect on the challenges and discuss what strategies worked best.
Engage in a class debate about the likelihood of monkeys rafting across the ocean. Split into groups to argue for or against the rafting theory, using evidence from the article and additional research. Conclude with a class vote on the most convincing argument.
Here’s a sanitized version of the transcript:
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Every single monkey in South America is a descendant of African monkeys. We know this because we’ve analyzed their DNA. However, South America and Africa are not close to each other, and even when those monkeys first arrived in South America, the continents were still very far apart. So how did monkeys get from Africa to South America? Interestingly, most scientists believe they took a raft.
Hi, I’m David, and this is MinuteEarth. When I say the monkeys took a raft, I don’t mean they built a sea-faring vessel. I mean they rode on a collection of driftwood, debris, and vines, or on a piece of marshland that broke off the mainland and floated away. However, the rafting hypothesis seems quite improbable at first glance. Consider all the factors that would need to align for a monkey rafting trip to occur.
First, a mat of vegetation—one that somehow had monkeys on it—would have had to break off and float out to sea, possibly due to a rare storm. Second, that mat would need to stay afloat for weeks without breaking apart. Third, the monkeys would need enough food and water on that raft to survive the journey. Fourth, the mat would have to land in a suitable habitat for monkeys. Lastly, enough monkeys of the right age and sex would need to survive to reproduce.
The probability of any of these events happening is incredibly small, and the chances of all of them occurring are astronomically tiny. However, there are no other plausible explanations. We know from studying plate tectonics that even 30 million years ago, when monkeys likely arrived, there were no land bridges connecting Africa and South America, so the monkeys did not simply walk there. Fossil studies indicate that those ancestral primates were not strong swimmers, so they couldn’t have paddled over. If they didn’t walk, swim, or fly, the only remaining option would be to float.
We’ve learned a few things that make a successful ancient rafting trip slightly more feasible than it initially seems. First, the powerful east-to-west equatorial currents were stronger back then, meaning that once a raft was adrift from Africa, it would head straight west and could reach South America in just a few weeks. This would reduce the need for luck in their journey. Second, there were times of the year when the Atlantic had very few waves, which would increase the chances of the raft’s survival. Third, it rained almost every day in tropical latitudes, ensuring the monkeys would have access to food and water.
Most importantly, given enough attempts, extremely unlikely events can occur. For example, if a storm strong enough to send a monkey-laden mat of vegetation into the sea happens once every two thousand years, over a few million years, there would be thousands of opportunities for such voyages to begin, and only one would need to succeed for old world monkeys to become new world monkeys.
In fact, scientists believe this kind of rafting also brought the ancestors of lemurs 400 miles from mainland Africa to Madagascar, and reptiles and rats about 600 miles from the South American coast to the Galapagos Islands. In 1995, scientists documented the voyage of a natural raft that carried 15 green iguanas more than 100 miles across the Caribbean to the island of Anguilla for the first time. It turns out that the world is vast enough and time is long enough for events that seem improbable to actually have occurred many times.
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This version maintains the original content while removing any informal language or potentially confusing phrases.
Monkeys – Primates that are typically small to medium-sized and are known for their agility and intelligence. – Monkeys play a crucial role in their ecosystems by dispersing seeds and maintaining the health of tropical forests.
Africa – A continent known for its diverse ecosystems, including savannas, rainforests, and deserts. – Africa is home to a wide variety of wildlife, including elephants, lions, and numerous species of birds.
South America – A continent rich in biodiversity, featuring the Amazon rainforest and the Andes mountains. – South America is known for its unique species, such as the jaguar and the capybara, which thrive in its diverse habitats.
Raft – A floating platform, often made of wood, used for transportation or as a habitat in aquatic environments. – Some animals, like certain insects and small mammals, use natural rafts of vegetation to travel across bodies of water.
Ocean – A vast body of saltwater that covers most of the Earth’s surface and is home to a wide variety of marine life. – The ocean is crucial for regulating the Earth’s climate and supporting marine ecosystems.
Currents – Large-scale flows of water within the ocean that move heat and nutrients around the planet. – Ocean currents play a vital role in distributing heat from the equator to the poles, affecting global climate patterns.
Fossils – The preserved remains or traces of ancient organisms that provide evidence of past life on Earth. – Fossils help scientists understand the evolution of life and the environmental conditions of the past.
Journey – A long trip or passage from one place to another, often involving exploration or migration. – The migration journey of monarch butterflies covers thousands of miles from North America to central Mexico.
Plants – Living organisms that typically produce their own food through photosynthesis and form the base of most ecosystems. – Plants are essential for life on Earth, providing oxygen, food, and habitat for countless species.
Survival – The ability of an organism to continue living and reproducing in its environment. – Adaptations such as camouflage and hibernation enhance an animal’s survival in challenging conditions.
