#6 How big was a Megalodon?

Read this article in 4 levels: Basic A1 (英検3級), Intermediate B1(英検2級), Advanced C1(英検1級), original version. Multiple choice content questions for each level. Free English reading practice. The more you read in English, the more your English will improve. Today, let’s read about the Megalodon, an ancient, giant shark.

A1 Beginner 英検3級
B1 Intermediate 英検2級
C1 Advanced 英検1級
Original article

A1 Level Beginner 英検3級

**How Big Was a Megalodon?**

A Megalodon was a very big shark, maybe as long as 20 buses lined up! It was much bigger than the sharks we know today.

Megalodons lived a long time ago, from 23 million years to 3.6 million years back. They liked warm water but sometimes went into cold water too. We don’t know exactly how big they were because we only find their teeth and part of their backbones. Sharks are made of something soft called cartilage, which doesn’t last long after they die. So, finding a whole Megalodon would be very lucky.

Sharks lose their teeth a lot. They have many teeth in rows and get new ones all the time. Megalodons had about 250 teeth and got new ones maybe every week. Their teeth are the only part that can turn into fossils. That’s how we guess how big they were.

The Megalodon was very strong and could eat a lot, but being too big wasn’t always good. A really big Megalodon needed to eat a lot, like 100,000 food every day, which was hard to find. Their big size also made them slow and less able to turn quickly.

They disappeared about 3.6 million years ago, maybe because it got too cold for them and there wasn’t enough food. The biggest animals had the hardest time surviving when the weather changed and food was scarce.

Questions

1. What was the Megalodon?
   – A) A dinosaur
   – B) A very big shark
   – C) A small fish
   – D) A kind of whale

2. How do we know about Megalodons?
   – A) From their bones
   – B) From their skin
   – C) From their teeth and part of their backbones
   – D) From stories

3. Why don’t we find complete Megalodon fossils?
   – A) They hid very well
   – B) They lived in deep water
   – C) They were made of cartilage
   – D) They moved too fast

4. How many teeth did Megalodons have?
   – A) About 250
   – B) Over 1000
   – C) Just one big tooth
   – D) None

5. How often did Megalodons get new teeth?
   – A) Every month
   – B) Once a year
   – C) Every day
   – D) Maybe every week

6. What was a problem for very big Megalodons?
   – A) They were too happy
   – B) They were too colorful
   – C) They needed a lot of food
   – D) They liked cold water

7. Why did Megalodons go extinct?
   – A) Because of the cold and not enough food
   – B) Because they slept too much
   – C) Because they got lost
   – D) Because they stopped growing teeth

8. Where did Megalodons prefer to live?
   – A) In warm water
   – B) On land
   – C) In the sky
   – D) In fresh water

answers 1B 2C 3A 4A 5D 6C 7A 8B

B1 Level Intermediate 英検2級

**How Big Was a Megalodon?**

The Megalodon was a huge shark, possibly up to 20 meters long, which is about the length of two buses end to end. It was part of the mackerel shark family, which includes sharks like the great white shark we see today. These sharks lived from 23 million to 3.6 million years ago, usually in warm waters, though sometimes they were found in colder waters too.

Figuring out the exact size of a Megalodon is tricky because we haven’t found a complete skeleton yet. Unlike dinosaurs, which left us lots of fossils, sharks, including Megalodons, are mostly made of cartilage. Cartilage doesn’t last long after death, so it’s rare to find these fossils. The only Megalodon fossils we’ve found are parts of their teeth and backbone. These fossils help scientists guess how big these sharks were.

Sharks, including Megalodons, lose their teeth often. Unlike humans, who have just two sets of teeth in a lifetime, sharks continuously grow new teeth. Megalodons had about 250 teeth in five rows and could replace them as often as every week. This means there could be millions of Megalodon teeth lying on the ocean floor. The teeth are the key to estimating the shark’s size since they’re the only parts that fossilize well.

So, how do scientists figure out a Megalodon’s size? They study the teeth and compare them to sharks living today, like the great white shark. By looking at the size and shape of the teeth, they can estimate that Megalodons could be up to 20 meters long. However, most were probably smaller than this. Being too big had its disadvantages, like needing a lot of food (about 100,000 calories a day) and moving slower.

Megalodons went extinct about 3.6 million years ago, possibly because of their large size. When the Earth’s climate changed, and an ice age reduced the warm waters they preferred, their food sources also dwindled. The biggest animals often struggle the most when the environment changes drastically, and for the Megalodon, this might have meant the end.

Questions

1. What family did Megalodons belong to?
   – A) Dolphin family
   – B) Seal family
   – C) Whale family
   – D) Mackerel shark family

2. Where did Megalodons prefer to live?
   – A) Warm water
   – B) Cold water
   – C) Freshwater lakes
   – D) On land

3. Why is it hard to know the exact size of Megalodons?

   – A) They were too fast

   – B) They lived too deep in the ocean

   – C) They were made mostly of cartilage

   – D) They are too small

4. How did sharks, including Megalodons, replace their teeth?

   – A) Continuously throughout their lives

   – B) Once in their lifetime

   – C) Every year on their birthday

   – D) They didn’t lose teeth

5. What are the only parts of Megalodons that fossilize well?

   – A) Their fins

   – B) Their skin

   – C) Their cartilage

   – D) Their teeth

6. What was a disadvantage of being a very large Megalodon?

   – A) They were happier

   – B) They needed a lot of food

   – C) They could fly

   – D) They were faster

7. Why did Megalodons go extinct?

   – A) Because they turned into whales

   – B) Because they moved to land

   – C) Because they got too hot

   – D) Because of climate change and food scarcity

8. How do scientists estimate the size of Megalodons?

   – A) By comparing their teeth to those of modern sharks

   – B) By using satellite images

   – C) By measuring the ocean depth

   – D) By guessing

answers 1D 2A 3C 4A 5D 6B 7D 8A

C1 Level Advanced 英検1級

**The Colossal Megalodon: Unraveling the Mysteries of a Prehistoric Giant**

The Megalodon, an ancient leviathan of the seas, has captivated the imagination of scientists and enthusiasts alike. This prehistoric mackerel shark, believed to reach lengths up to 20 meters—comparable to the combined length of two London buses—reigned supreme in the marine food chain. Belonging to a family that includes the formidable great white shark, Megalodons thrived from approximately 23 million to 3.6 million years ago, predominantly in warm waters, though evidence suggests they occasionally ventured into cooler realms.

The quest to pinpoint the exact dimensions of this gargantuan shark faces a significant obstacle: a lack of complete skeletal remains. Unlike many dinosaurs that left behind extensive fossil records, the Megalodon’s primarily cartilaginous structure offers little in the way of post-mortem preservation. Cartilage, unlike bone, rapidly disintegrates upon death, leaving scant evidence of the shark’s existence save for the occasional tooth or vertebral fragment. Thus, the dream of unearthing a complete Megalodon fossil remains just that—a dream, with the discovery of such a specimen hinging on extraordinary luck.

Megalodon’s dental records, however, tell a fascinating story of adaptation and survival. Sharks, in general, are known for their prodigious tooth replacement abilities, shedding and regenerating teeth throughout their lifespan. The Megalodon was no exception, boasting an arsenal of approximately 250 teeth arranged in five rows, with frequent replacements ensuring a constant edge for capturing and dismembering prey. This relentless dental turnover contributes to the vast number of Megalodon teeth scattered across the ocean floor, providing invaluable insights into the shark’s size and feeding habits.

Analyzing these teeth, scientists embark on a complex journey to extrapolate the Megalodon’s size, comparing them with the dentition of contemporary sharks to sketch a portrait of this ancient predator. Through meticulous examination, it is surmised that while some Megalodons could indeed reach the upper size limit of 20 meters, the majority were likely smaller. The evolutionary calculus behind this size variation reveals a balance between the advantages of enormity—such as enhanced hunting capabilities and thermal regulation—and the drawbacks, notably the metabolic demands of maintaining such a massive physique and the diminished agility that comes with greater bulk.

The demise of the Megalodon approximately 3.6 million years ago remains a subject of scientific inquiry, with prevailing theories suggesting a confluence of climatic shifts and food scarcity. The onset of an ice age heralded a chilling of the seas and a reduction in habitable warm water zones, critically impacting the Megalodon’s prey base. As marine ecosystems reeled from these changes, the Megalodon, like many apex predators of its time, found itself on the brink of extinction, unable to adapt to the rapidly transforming environment.

Questions

1. What is a defining characteristic of the Megalodon’s family?

   – A) Small size

   – B) Inclusion of the great white shark

   – C) Ability to live on land

   – D) Feathered fins

2. What primarily hampers the determination of Megalodon’s exact size?

   – A) The depth of the ocean

   – B) The absence of eyewitnesses

   – C) The lack of complete skeletal fossils

   – D) The destruction of their habitat

3. Why does cartilage rarely fossilize?

   – A) It is too hard

   – B) It is eaten by other animals

   – C) It disintegrates rapidly after death

   – D) It turns into bone

4. How did Megalodons compensate for the loss of teeth?

   – A) Through rapid and continuous tooth replacement

   – B) By growing larger teeth

   – C) By developing stronger jaws

   – D) By changing their diet

5. What is the significance of the Megalodon’s teeth found on the ocean floor?

   – A) They are used as currency

   – B) They indicate the presence of gold

   – C) They provide insights into the shark’s size and feeding habits

   – D) They prove that Megalodons could breathe air

6. Why might not all Megalodons have reached the maximum size of 20 meters?

   – A) They preferred to remain hidden

   – B) They were afraid of larger predators

   – C) They lacked the necessary nutrients

   – D) The disadvantages of being too large outweighed the benefits

7. Which factor contributed to the Megalodon’s extinction?

   – A) Meteor impact

   – B) Volcanic eruptions

   – C) Invasion of alien species

   – D) Climate change and food scarcity

8. During what period did Megalodons likely become extinct?

A) The Jurassic period

B) The onset of an ice age

C) The Cretaceous period

D) The Renaissance

answers 1B 2C 3D 4B 5C 6D 7D 8B

Original article

**How big was a Megalodon?**

The largest ones could have been 20 meters long. Megalodon was a species of giant mackerel shark. Mackerel sharks have two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth that extends behind the eyes. Great white sharks are in this family. Megalodons lived between 23 million and 3.6 million years ago. They tended to live in warmer water, but some have been found in colder water as well.

There is no way of knowing the exact size of a Megalodon because there are no complete fossils. Many other dinosaurs have been kind enough to become fossils so we can see their size and how they lived. Megalodon didn’t do this because, as a shark, it was made of mostly cartilage. Cartilage decomposes very quickly when sharks die and doesn’t hang around long enough to become a fossil. That isn’t to say that there won’t be a Megalodon fossil, but we’d have to be very lucky. Some soft animals, like jellyfish, live fossilized impressions when they die on something soft, like mud, and there might be an undiscovered Megalodon fossil somewhere, waiting to be discovered. The only parts of the Megalodon that have been discovered are the teeth and some parts of the vertebrae. We have been very lucky to have the vertebrae fossils, but the teeth are far more common.

Megalodon was a shark and sharks lose their teeth all of the time. When we are born, we have our “milk” teeth, which are replaced by the adult teeth that we keep throughout our lives. If we lose our teeth, that is it. Sharks need very sharp teeth to be able to rip and tear their prey. They also lose a lot of teeth when they are attacking their prey because they can be knocked out. To keep them sharp, and to replace the teeth that are knocked out, sharks replace their teeth all the time. Megalodon probably had 250 teeth spread over 5 rows. They probably replaced these teeth every week and thousands of teeth lay at the bottom of the sea. Sharks lose about 35,000 teeth in their lifetime, so there are probably millions of fossilized Megalodon teeth at the bottom of the sea. The teeth are the only part of a shark that are made of bone and they are covered in an enamel that protected them and ensured that so many of them would be fossilized.

So, how big was the Megalodon? The only way to work that out is to look at the teeth and try to extrapolate out. That is a very difficult, but not impossible task to do. If an archaeologist found a human tooth after we had gone extinct, they could probably work out our rough size by looking at how many teeth we could fit in our mouths and how powerful they were. Experts have done the same thing with Megalodon teeth. They can see by the shapes and size of them how many would fit in a mouth, and they can compare that to modern great white sharks. The two animals were probably of a similar shape. Analysis of the teeth gives a probably maximum size of about 20 meters. Many of them would have been smaller, but some could have been bigger.

Most of them were probably smaller than 20 meters because the extra size is not really worth it for the shark. Up to a certain point, they get many benefits from being larger. They are more powerful, they can hunt more food, they are able to regulate their body temperature more efficiently, they can swim faster, and so on. However, if they are too large, they will be extremely heavy, which would slow them down. A 20 m shark would have weighed over 100 tons, which would have made them less maneuverable. They would also have had trouble finding enough food. A 20 meter shark would need about 100,000 calories a day. That was probably possible, but it would have been difficult to sustain. Their sheer size gave them phenomenally strong jaws as well. A modern great white shark has a bite strength of about 18,000 Newtons. The Megalodon probably has a bite force of 182,000 Newtons.

Megalodons went extinct about 3.6 million years ago. Their size might have been one of the reasons for this. Just like when the dinosaurs went extinct, the animals that were able to hide and survive on less food survived, while the dinosaurs that needed to eat a lot died off. Probably, there was a food shortage and the Megalodons couldn’t get enough to feed themselves. 3.6 million years ago was when the seas started to cool down and there was an ice age. Megalodons lived in warmer water, so their territory decreased, but their food also disappeared as well. About 60% of all marine life died out during this time. The largest animals were the first to go extinct because they couldn’t feed themselves.

Questions

1. What material are shark bodies primarily made of, leading to a scarcity of complete fossils?

   – A) Bone

   – B) Muscle

   – C) Skin

   – D) Cartilage

2. Which family do Megalodons belong to?

   – A) Mackerel shark family

   – B) Whale shark family

   – C) Hammerhead shark family

   – D) Tiger shark family

3. Where have Megalodon fossils been predominantly found?

   – A) In deep sea trenches

   – B) In freshwater lakes

   – C) Along coastal regions

   – D) In both warmer and colder water

4. How do sharks, including Megalodons, manage the loss of their teeth?

   – A) By growing a single set throughout their lives

   – B) By using the same set of teeth without loss

   – C) By hardening their gums

   – D) By continuously replacing them

5. How many teeth did a Megalodon likely have at any given time?

   – A) 100

   – B) 150

   – C) 200

   – D) 250

6. What is the reason Megalodons were not larger than 20 meters, according to the article?

   – A) Because they preferred shallow waters

   – B) The disadvantages of being too large

   – C) Lack of evolutionary pressure

   – D) They could not swim in deep water

7. What contributed to the extinction of the Megalodon?

   – A) Global warming

   – B) Overfishing

   – C) Climate change and food scarcity

   – D) Asteroid impact

8. During what time period did Megalodons live?

   – A) 100 million to 65 million years ago

   – B) 1 million to 10,000 years ago

   – C) 23 million to 3.6 million years ago

   – D) 500 million to 300 million years ago

answers 1D 2A 3B 4D 5A 6B 7C 8C

Image By Sergiodlarosa – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=71545069

Image By Lonfat – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1721034

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