Footprints in the Muds of Time Reading Answers

Jul 14, 2025

Footprints in the Muds of Time is an IELTS Reading Answer that contains 13 questions and needs to be completed within 20 minutes. Footprints in the Muds of Time Reading answers, also help you to prepare for your IELTS exam. Footprints in the Muds of Time Consist of questions like: Do the following statements agree with the claims of the writer in Reading Passage and Choose no more than three words only. Participants should go through the IELTS Reading passage to recognize synonyms, identify keywords, and answer the questions.

Footprints in the Muds of Time Reading Answers discusses the history of dinosaurs. Candidates can use IELTS reading practice questions and answers to enhance their performance in the reading section.

Check: Get 10 Free Sample Papers
Check: Register for IELTS Coaching - Join for Free Trial Class Now

Topic:

The dinosaurs may have risen to power in as little as 10,000 years ...

Everybody knows that the dinosaurs became extinct as a result of a large asteroid; something big hit the Earth 65 million years ago and, when the dust had fallen, so had the great reptiles. There is thus a nice, if ironic, symmetry in the idea that a similar impact brought about the dinosaurs' rise. That is the thesis proposed by Paul Olsen of Columbia University.

Dinosaurs first appear in the fossil record 230 million years ago, during the Triassic period. But they were mostly small, and they shared the Earth with lots of other sorts of reptile. It was in the subsequent Jurassic period, which began 202 million years ago, that they overran the planet and turned into the monsters realistically depicted in modern books and movies. Dr Olsen and his colleagues are not the first to suggest that the dinosaurs inherited the Earth as the result of an asteroid strike. But they are the first to show that the takeover did, indeed, happen in a geological eye blink.

Dinosaur skeletons are rare. Dinosaur footprints are, however, surprisingly abundant. And the size of the prints is as good an indication of the size of the beasts as are the skeletons themselves. Dr Olsen and his colleagues therefore concentrated on prints, not bones. The prints in question were made in eastern North America, a part of the world then full of rift valleys similar to those in East Africa today. Like the modern African rift valleys, the Triassic/Jurassic American ones contained lakes, and these lakes grew and shrank at regular intervals because of climatic changes.

Rocks from this place and period can be dated to within a few thousand years. As a bonus, squishy lake-edge sediments are just the things for recording the tracks of passing animals.

By dividing the labour between them, the research team were able to study such tracks at 80 sites and look at 18 so-called 'ichnotaxa'. These are recognisable types of footprint that cannot be matched precisely within the species of animal that left them. But they can be matched with a general sort of animal, and thus act as an indicator of the fate of that group, even when there are no bones to tell the story.

Their findings show that five of the ichnotaxa disappear before the end of the Triassic, and four march confidently across the boundary into the Jurassic. Six, however, vanish at the boundary, or only just splutter across it; and three appear from nowhere, almost as soon as the Jurassic begins.

That boundary itself is suggestive. The first geological indication of the impact that killed the dinosaurs was an unusually high level of indium in rocks at the end of the Cretaceous period, when the beasts disappear from the fossil record. Iridium is normally rare at the Earth's surface, but it is more abundant in meteorites. When people began to believe the impact theory, they started looking for other Cretaceous-end anomalies.

One that turned up was a surprising abundance of fern spores in rocks just above the boundary layer - a phenomenon known as 'fern spike' That matched the theory nicely. Many modern ferns are opportunists. They cannot compete against plants with leaves, but if a piece of land is cleared by, say, a volcanic eruption, they are often the first things to set up shop there. An asteroid strike would have scoured much of the Earth of its vegetable cover, and provided a paradise for ferns. A fem spike in the rocks is thus a good indication that something terrible has happened.

The surprises are how rapidly the new ichnotaxa appeared and how quickly they increased in size. Dr Olsen and his colleagues suggest that the explanation for this may be a phenomenon called ecological release. This is seen today when reptiles (which in modem times tend to be small creatures) reach islands where they face no competitors. The most spectacular example is on the Indonesian island of Komodo, where local lizards have grown so large that they are often referred to as dragons. The dinosaurs, in other words, could flourish only when the competition had been knocked out.

That leaves the question of where the impact happened. No large hole in the Earth's crust seems to be 202 million years old. It may, of course, have been overlooked. Old craters are eroded and buried, and not always easy to find. Alternatively, it may have vanished. Although continental crust is more or less permanent, the ocean floor is constantly recycled by the tectonic processes that bring about continental drift. There is no ocean floor left that is more than 200 million years old, so a crater that formed in the ocean would have been swallowed up by now.

There is a third possibility, however. This is that the crater is known, but has been misdated. The Manicouagan 'structure', a crater in Quebec, is thought to be 214 million years old. It is huge - some 100 kilometres across - and seems to be the largest of between three and five craters that formed within a few hours of each other as the lumps of disintegrated comet hit the Earth one by one. Such an impact would surely have had a perceptible effect on the world, but the rocks from 214 million years ago do not record one. It is possible, therefore, that Manicouagan has been misdated. That will be the next thing to check.

Questions 1 - 6

Do the following statements agree with the claims of the writer in Reading Passage 1? Write

YES if the statement agrees with the claims of the writer

NO if the statement contradicts the claims of the writer

NOT GIVEN if it is impossible to say what the writer thinks about this

1. There is still doubt about the theory that an asteroid strike killed the dinosaurs.

Answer: NO

Supporting statement: "Everybody knows that the dinosaurs became extinct as a result of a large asteroid..."

Keywords: asteroid strike, extinct, dinosaurs

Keyword Location: Paragraph 1, line 1

Explanation: The passage states the asteroid extinction theory as common knowledge, with no mention of ongoing doubt. Thus, it contradicts the idea that the theory is still in question.

2. Books and the cinema have exaggerated the size of dinosaurs.

Answer: NOT GIVEN

Explanation: The passage notes that dinosaurs were realistically depicted in modern media but does not state whether these depictions were exaggerated, so no conclusion can be drawn.

3. Other scientists have rejected Olsen's idea of a sudden dinosaur occupation of the Earth.

Answer: NOT GIVEN

Explanation: The passage says Olsen’s team was the first to show rapid takeover but does not discuss whether others accepted or rejected the theory, so the writer's stance is not revealed.

4. Dinosaur footprints are found more frequently than dinosaur skeletons.

Answer: YES

Supporting statement: "Dinosaur skeletons are rare. Dinosaur footprints are, however, surprisingly abundant."

Keywords: footprints, skeletons, rare, abundant

Keyword Location: Paragraph 3, lines 1–2

Explanation: The passage clearly compares the rarity of skeletons with the abundance of footprints, supporting the claim.

5. Ichnotaxa offer an exact identification of a dinosaur species.

Answer: NO

Supporting statement: "These are recognisable types of footprint that cannot be matched precisely within the species..."

Keywords: ichnotaxa, exact identification, species

Keyword Location: Paragraph 4, line 3

Explanation: The passage explicitly says ichnotaxa cannot identify exact species, only general types of animals, directly contradicting the statement.

6. There is evidence that some groups of dinosaurs survived from the Triassic period into the Jurassic period.

Answer: YES

Supporting statement: "Four march confidently across the boundary into the Jurassic."

Keywords: ichnotaxa, survived, Triassic, Jurassic

Keyword Location: Paragraph 5, line 2

Explanation: This statement shows that some footprint types, and thus some groups of dinosaurs, continued from the Triassic into the Jurassic, confirming their survival across the boundary.

Questions 7 - 13

Choose NO MORE THAN THREE WORDS.

Dr Olsen's group believe that the sudden increase in the size of dinosaurs may have

been due to something known as 7………………………

Answer: ecological release

Supporting statement: "Dr Olsen and his colleagues suggest that the explanation for this may be a phenomenon called ecological release."

Keywords: sudden increase, size, ecological release

Keyword Location: Paragraph 8, line 2

Explanation: The passage directly links the phenomenon of "ecological release" to the rapid growth in dinosaur size following the extinction of competitors, supporting this answer.

. A current example of this can be found on Komodo Island in Indonesia, where some of the lizards are commonly called 8…………………

Answer: dragons

Supporting statement: "...local lizards have grown so large that they are often referred to as dragons."

Keywords: Komodo Island, lizards, dragons

Keyword Location: Paragraph 8, line 4

Explanation: The comparison with Komodo Island is used to illustrate how animals can grow significantly in size in the absence of competition, and the lizards there are called "dragons" due to their size.

because of their size. Apparently, they have grown this big because they do not have any 9……………………. .

Answer: competitors

Supporting statement: "...where they face no competitors."

Keywords: no competitors, Komodo lizards

Keyword Location: Paragraph 8, line 3

Explanation: The absence of competitors on islands like Komodo is cited as the reason for the large size of reptiles, supporting this answer.

The asteroid strike that may have cleared the way for dinosaurs to become the dominant group probably occurred 202 million years ago. According to the writer, there are three possible reasons why we have not found a large hole in the Earth's crust dating back 202 million years. First, it may have been 10…………….

Answer: overlooked

Supporting statement: "It may, of course, have been overlooked. Old craters are eroded and buried..."

Keywords: overlooked, crater, scientists

Keyword Location: Paragraph 9, line 2

Explanation: The passage suggests that craters can be missed due to erosion and burial, meaning scientists might have overlooked it.

by scientists because craters are easily covered up. Or it could have 11…………….;

Answer: vanished

Supporting statement: "Alternatively, it may have vanished... the ocean floor is constantly recycled..."

Keywords: vanished, crater, no longer exists

Keyword Location: Paragraph 9, line 5

Explanation: A second possibility for the missing crater is that it disappeared due to ocean floor recycling, supporting the use of "vanished."

for example, if the hole had been in the ocean, it would no longer exist be the 12…………….

Answer: tectonic processes

Supporting statement: "...the ocean floor is constantly recycled by the tectonic processes that bring about continental drift."

Keywords: tectonic processes, continental drift

Keyword Location: Paragraph 9, line 6

Explanation: Tectonic processes are mentioned as the mechanism by which old ocean floor—and any craters in it—would have been destroyed.

That produce continental drift. Thirdly, the hole could still exist but have been 13................

Answer: misdated

Supporting statement: "It is possible, therefore, that Manicouagan has been misdated."

Keywords: misdated, crater

Keyword Location: Paragraph 10, last line

Explanation: The third possibility is that a known crater, such as the Manicouagan, is actually from a different period due to dating errors, making "misdated" the correct answer.

Check IELTS reading samples: