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Test yourself! Take this All About Crabs! Quiz | Invertebrates

This quiz will test your crab knowledge, and feature some common British crab species.

A multiple-choice quiz by JSV58194180. Estimated time: 5 mins.

Author
JSV58194180

Time
5 mins

Type
Multiple Choice

Quiz #
301,858

Updated
Dec 03 21

# Qns
10

Difficulty
Tough

Avg Score
6 / 10

Plays
877

Last 3 plays: Guest 90 (2/10), Guest 86 (4/10), Triviaballer (4/10).

One at a Time - Single Page - Timed Game

Question 1 of 10

1. Crabs belong to a group of animals known as the Crustaceans.

True

False

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Question 2 of 10

2. The scientific name for the common (or green) shore crab is what? Hint

Cancer pagurus

Necora puber

Pagurus bernhardus

Carcinus maenas

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Question 3 of 10

3. Male adult edible crabs generally have larger chelipeds (claws) than female adult edible crabs.

True

False

4. Velvet swimmer crabs are very distinctive crabs. They are found under rocks and in small pools on the shore. Their rearmost legs are flattened so they can swim better (hence the name). When they are adults, what colour are their eyes? Hint

Red

Yellow

Black

Grey

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Question 5 of 10

5. Crabs can support sea anemones on their shells.

True

False

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Question 6 of 10

6. Which of the following facts is true about the masked crab (Corystes cassivelaunus)? Hint

The two antennae between the eyes are modified into a tube so they can inhale seawater and breathe

Their shells (carapaces) can grow to over 20cm in width

They occupy winkle and whelk shells like hermit crabs

They burrow forwards into the sand

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Question 7 of 10

7. The male Pea Crab spends its entire life inside a shellfish (for example, a mussel).

True

False

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Question 8 of 10

8. Spider crabs are named as such because they have eight long legs, and typically, their claws are not as big as other crabs. In the water therefore, they often resemble spiders. Roughly what shape are their shells? Hint

Triangular

Circular

Square

Hexagonal

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Question 9 of 10

9. The European lobster has the scientific name Homarus gammarus. What is the scientific name of the American lobster? Hint

Homarus pacificus

Homarus americanus

Homarus caribbeanicus

Homarus atlantica

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Question 10 of 10

10. The long-clawed porcelain crab has just three pairs of legs, not four.

True

False

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Nov 02 2024 : Guest 90: 2/10
Sep 27 2024 : Guest 86: 4/10
Sep 26 2024 : Triviaballer: 4/10

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Quiz Answer Key and Fun Facts

1. Crabs belong to a group of animals known as the Crustaceans.

Answer: True

Crabs, shrimp, lobsters, barnacles, etc, all belong to the taxonomic sub-phylum Crustacea. Crustaceans have a soft body protected by a hard shell on the outside known as an exoskeleton.

2. The scientific name for the common (or green) shore crab is what?

Answer: Carcinus maenas

The other three scientific names belong to other crustaceans. Cancer pagurus is the edible crab. It is very common and has a very recognisable 'pie-crust' style shell. Pagurus bernhardus is the common hermit crab. The hermit crab commonly occupies winkle and whelk shells, and once it gets too large for the shell, it will seek out a larger one.

3. Male adult edible crabs generally have larger chelipeds (claws) than female adult edible crabs.

Answer: True

This is true. Males have larger claws so they can fend off other competing males (and a lesser factor is for displaying to females). Generally, the larger your claws, the more fights you will win!

Answer: Red

They have piercing red eyes, and should hopefully put you off touching them! They are very aggressive crabs, and will not hesitate to nip you with their powerful claws. Juveniles tend to have black eyes, and gradually as they grow up, their eyes turn red.

5. Crabs can support sea anemones on their shells.

Answer: True

Crabs can support a variety of usually sessile (non-moving) organisms on their shells (or carapaces). This is particularly good for anemones, who will be transported around by the crab, and stand a better chance of catching some food. Barnacles and keel worms are other organisms that colonise on crab shells.

6. Which of the following facts is true about the masked crab (Corystes cassivelaunus)?

Answer: The two antennae between the eyes are modified into a tube so they can inhale seawater and breathe

Masked crabs bury backwards into the sand, and therefore the antennae tube is necessary for them to breathe. They are very small crabs, and their shells are longer than they are wide. Their shell length rarely exceeds 2cm.

7. The male Pea Crab spends its entire life inside a shellfish (for example, a mussel).

Answer: False

It is the female that spends her life inside a shellfish. The male is a very active swimmer, and fertilises the females eggs when the shell opens to feed.

Answer: Triangular

Spider crabs have triangular shaped shells. Crabs such as the marbled rock crab have very square shells. I'll bet you can guess what shape the shell of the circular crab is!

9. The European lobster has the scientific name Homarus gammarus. What is the scientific name of the American lobster?

Answer: Homarus americanus

The American lobster is very similar to its European counterpart, and rare examples of the American lobster have even been found off the south coast of England! European lobsters can grow to over 1 metre in length, and by that time, keel worms and barnacles have colonised on the hard shell.

10. The long-clawed porcelain crab has just three pairs of legs, not four.

Answer: False

The porcelain crab does have the correct number of pairs of legs, but the fourth pair are hidden under the carapace, so most observers never see them. The broad-clawed porcelain crab also hides its fourth pair of legs.

Source: Author JSV58194180

This quiz was reviewed by FunTrivia editor crisw before going online.
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