Dinosaurs & Prehistoric Life · Unit 7
Flying and Swimming Reptiles
Pterosaurs, plesiosaurs and the sea monsters that were not dinosaurs
The great flying and swimming reptiles of the Mesozoic are usually filed under dinosaurs and belong to entirely separate lineages that happened to live at the same time.
The unit covers pterosaurs, plesiosaurs, ichthyosaurs and mosasaurs, and makes clear why none of them qualifies as a dinosaur.
This unit breaks down into 19 short steps and 111 questions, starting at difficulty 1 and building to 3. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.
- Steps
- 19
- Questions
- 111
- Difficulty
- 1-3
What this unit covers
- Mosasaurs
- Pterosaurs
- Why They Are Not Dinosaurs
- Ichthyosaurs
- Plesiosaurs
Where this fits
Follows What Is a Dinosaur? The definition there is what this unit tests.
Where people slip
Pterosaurs and birds evolved flight independently. Their wings are built differently - one long finger against a whole feathered forelimb - and neither descends from the other.
How the unit is structured
Flying and Swimming Reptiles runs as 19 short steps that unlock in order. 14 are practice rounds and 5 are challenge rounds that pull together everything before them. Questions start at difficulty 1 and climb to 3 as you progress.
Challenge rounds
Example questions
30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 111 in the unit altogether.
Ichthyosaurs
- True or falseLevel 1
1. Ichthyosaurs died out well before the dinosaurs did.
Answer: True
True. They disappeared around ninety million years ago.
- Fact or fibLevel 2
2. Ichthyosaurs laid their eggs on beaches like turtles.
Answer: False
False. They gave birth to live young in the water.
- Fill the blankLevel 2
3. Ichthyosaurs breathed ____ and had to surface regularly.
- aircorrect
- water
- steam
- sand
They were reptiles with lungs, not fish with gills.
- Multiple choiceLevel 2
4. What was remarkable about ichthyosaur eyes?
- They were enormouscorrect
- They were on stalks
- They glowed in the dark
- They had no eyes at all
Some had eyes the size of dinner plates, the largest of any known animal.
- Type the answerLevel 2
5. Which sea reptile group looked most like modern dolphins?
Answer: ichthyosaurs
Ichthyosaurs evolved a very similar body shape to dolphins.
- Fact or fibLevel 2
6. Ichthyosaurs are the only major marine reptile group that had already vanished before the K-Pg extinction.
Answer: True
True. They disappeared roughly 90 million years ago.
Mosasaurs
- Fact or fibLevel 1
7. The first mosasaur fossil was found in a chalk mine near Maastricht.
Answer: True
True, which is why the last stage of the Cretaceous is called the Maastrichtian.
- Multiple choiceLevel 1
8. What were mosasaurs?
- Giant swimming lizardscorrect
- Flying reptiles
- Land dinosaurs
- Early whales
Mosasaurs were huge sea lizards that ruled the oceans late in the Cretaceous.
- True or falseLevel 1
9. Mosasaurs died out at the same time as the last dinosaurs.
Answer: True
True. They vanished in the same extinction 66 million years ago.
- Choose all that applyLevel 2
10. Which animals swam in Cretaceous seas? Pick all that apply.
- Mosasaurscorrect
- Plesiosaurscorrect
- Ammonitescorrect
- Tyrannosaurus
Mosasaurs, plesiosaurs and ammonites all shared those waters.
- Type the answerLevel 2
11. Which group of giant marine lizards ruled the late Cretaceous seas?
Answer: mosasaurs
Mosasaurs were the top ocean predators of their time.
- Choose all that applyLevel 3
12. Which marine reptiles survived until the very end of the Cretaceous? Pick all that apply.
- Mosasaurscorrect
- Plesiosaurscorrect
- Ichthyosaurs
- Trilobites
Mosasaurs and plesiosaurs both persisted to the extinction, while ichthyosaurs had already gone.
Plesiosaurs
- Multiple choiceLevel 1
13. What did plesiosaurs use to swim?
- Four flipperscorrect
- A single tail fin only
- Wings
- Legs for walking
They rowed through the water with four large flippers.
- True or falseLevel 1
14. Plesiosaurs lived in the sea but breathed air.
Answer: True
True. Like whales today, they had to come to the surface.
- Choose all that applyLevel 2
15. Which are true about plesiosaurs? Pick all that apply.
- They breathed aircorrect
- They gave birth in the watercorrect
- They had four flipperscorrect
- They laid eggs on land
They breathed air, gave birth at sea and had four flippers.
- Fact or fibLevel 2
16. Fossils show plesiosaurs gave birth to live young rather than laying eggs on land.
Answer: True
True. A fossil mother has been found with a baby inside.
- Fill the blankLevel 2
17. Short-necked plesiosaurs with huge heads are called ____.
- pliosaurscorrect
- pterosaurs
- pachyderms
- placoderms
Pliosaurs were the top predators of many Mesozoic seas.
- Type the answerLevel 2
18. Which long-necked sea reptile group swam with four flippers?
Answer: plesiosaurs
Plesiosaurs are famous for long necks and paddle limbs.
Pterosaurs
- Multiple choiceLevel 1
19. Which giant pterosaur was as tall as a giraffe when standing?
- Quetzalcoatluscorrect
- Pterodactylus
- Dimorphodon
- Rhamphorhynchus
Quetzalcoatlus had a wingspan of about ten metres.
- Picture questionLevel 1
20. 🦅 Which group does this flying animal picture stand for in the age of dinosaurs?
- Pterosaurscorrect
- Sauropods
- Trilobites
- Mammoths
Pterosaurs were the fliers of the Mesozoic.
- True or falseLevel 1
21. Pterosaurs were the first backboned animals to fly using their own power.
Answer: True
True. They took to the air long before birds or bats.
- Choose all that applyLevel 2
22. Which features helped pterosaurs fly? Pick all that apply.
- Hollow, thin-walled bones
- Air sacs linked to the lungscorrect
- A large breastbone for musclescorrect
- Feathered wings like birds
Hollow bones, air sacs and a large chest anchor for flight muscles all helped.
- Fact or fibLevel 2
23. Pterodactyl is the popular name people often use for pterosaurs.
Answer: True
True, although Pterodactylus was only one small kind of pterosaur.
- Fill the blankLevel 2
24. Pterosaur bones were ____, which helped them fly.
- hollowcorrect
- solid lead
- made of wood
- filled with water
Hollow bones keep the skeleton light and strong.
Why They Are Not Dinosaurs
- Build the sentenceLevel 1
25. Build a sentence about Mesozoic reptiles.
Answer: Flying reptiles were not dinosaurs
Flying and swimming reptiles were not dinosaurs.
- Multiple choiceLevel 1
26. What do all dinosaurs have in common that sea reptiles do not?
- Upright legs under the body for life on landcorrect
- Gills
- Flippers
- Wings
Dinosaurs are land animals with legs held straight beneath the body.
- Odd one outLevel 1
27. Which of these IS a dinosaur?
- Iguanodoncorrect
- Pteranodon
- Elasmosaurus
- Mosasaurus
Iguanodon is a dinosaur. The others are marine or flying reptiles.
- Choose all that applyLevel 2
28. Which marine animals also swam in Mesozoic seas? Pick all that apply.
- Sharkscorrect
- Ammonitescorrect
- Giant sea turtlescorrect
- Blue whales
Sharks, ammonites and giant sea turtles all shared the water.
- Fact or fibLevel 3
29. Birds are the only flying descendants of dinosaurs alive today.
Answer: True
True. Pterosaurs left no descendants at all.
- Put in orderLevel 3
30. Put these evolutionary events in order.
Answer: Vertebrates move onto land -> Archosaurs appear -> Pterosaurs and dinosaurs diverge -> Birds evolve from theropods
Land vertebrates came first, then archosaurs, then pterosaurs and dinosaurs, then birds.
Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.
How you practise
This unit mixes 11 different question formats, so you are recalling and applying rather than recognising the same layout every time.
- Build the sentence
- Choose all that apply
- Fact or fib
- Fill the blank
- Multiple choice
- Odd one out
- Picture question
- Put in order
- Sort into groups
- True or false
- Type the answer
Practise Flying and Swimming Reptiles
111 questions across 19 steps. Start with step one and crawl at your own pace.
Play this unitRead about Flying and Swimming Reptiles
Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.
More units in Dinosaurs & Prehistoric Life
- What Is a Dinosaur?What dinosaurs were, when they lived and how we name them
- Famous DinosaursTyrannosaurus, Triceratops, Stegosaurus and the other stars
- Meat Eaters and Plant EatersTeeth, claws, defences and what dinosaurs ate
- Fossils and Fossil HuntingWhat fossils are, how they form and how they are found
- The Age of DinosaursTriassic, Jurassic and Cretaceous, and how deep time works
- Eggs, Nests and Growing UpDinosaur eggs, nests, babies and family life
- The Great ExtinctionThe asteroid, the volcanoes and who survived
- Dinosaurs and BirdsFeathers, Archaeopteryx and the dinosaurs still alive today