The Horseshoe Crab Reading Answers

Jul 4, 2025

The Horseshoe Crab Reading Answers is an IELTS Reading Answer that contains 14 questions and needs to be completed within 20 minutes. This reading answer also helps you to prepare for your IELTS exam. The Horseshoe Crab Reading Answers consists of questions like: Which section contains the following information? Write the correct letter, A—F. Choose two letter, A - E. According to the writer, which two of the following are true about the characteristics of horseshoe crabs? And according to the writer, in which two ways is horseshoe crab blood different from that of most other animals? Choose one word only for each answer.

Participants should go through the IELTS Reading passage to recognise synonyms, identify keywords, and answer the questions. It's critical to comprehend the guidelines for every question type and create effective ways to manage time if you wish to receive excellent band scores. Candidates can use IELTS reading practice questions and answers to enhance their performance in the reading section.

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Topic:

THE HORSESHOE CRAB

A.One of the world's oldest animal species, the horseshoe crab, is found along the east coast of the United States and Mexico. Fossil records indicate this creature dates back 450 million years, and it has changed very little over time. This is because its anatomy has been so successful. In fact, the horseshoe crab is more closely related to spiders, scorpions and ticks than it is to true crabs and other crustaceans.

B.The soft body of the horseshoe crab is protected by a large oval shell with jagged, point spines. The two-part body consists of a head and an abdominal region. The head region contains a brain, heart, mouth, four eyes and six pairs of legs. What is significant is that horseshoe crabs possess the rare ability to regrow lost limbs. They also use crawling as their primary means of movement, and commonly bury themselves under the surface of the sand. However, in the water, they will occasionally turn onto their backs and swim upside-down. The mouth of the horseshoe crab is located between the twelve legs. They can only eat when crawling, as the motion allows them to open and close their mouths. Their diet consists mainly of worms and clams. The abdominal region contains muscles for movement and is for breathing. A long spine forming a tail, called a telson, is located behind the abdominal region. Although this part of the body looks intimidating, it is not dangerous, poisonous or used to sting. Horseshoe crabs use it to flip over if they happen to be pushed on their backs, but this is only possible under the sea. Every year, about 10 percent of the horseshoe crab breeding population dies while on the beach, when rough surf flips the creatures onto their backs, a position from which they often cannot right themselves.

C.Another distinctive feature of horseshoe crabs is that they do not have hemoglobin (a protein that contains the mineral iron), which gives blood its red color. Hemoglobin is the basis of oxygen transport in the blood of mammals, reptiles and birds. Rather, the blood of horseshoe crabs has a copper-containing protein called hemocyanin. Hemocyanin is dark blue when it is transporting oxygen and colorless when it is not. The oxygen is also transported in a fluid on the exterior of the cell, in contrast to most animals, where oxygen molecules are transported inside red blood cells. This makes horseshoe crab blood valuable to scientists. Horseshoe crab blood contains enzymes that are extremely sensitive to toxic bacteria and fungi. In fact, these enzymes are used by astronauts in the International Space Station to test surfaces for unwanted bacteria and fungi. Another application is a protein from horseshoe crab blood that is under investigation as an antibiotic.

D.The horseshoe crab faces the greatest dangers in early life. Between April and June, adult horseshoe crabs travel from deep ocean waters to converge on beaches. Crawling out of the sea and onto the beach is especially common at high tides during full and new moons. The males arrive first and await the females for breeding. Female horseshoe crabs communicate by releasing a scent to signal to the males. The female horseshoe crabs create nests by digging holes in the sand and laying between 60,000 and 120,000 eggs at a time before covering them with sand for protection. Most eggs do not survive the hatching period before being eaten, as the eggs are a food source for numerous birds, reptiles and fish.

If the egg does survive, the young horseshoe crab will hatch after five weeks. Referred to as larvae, they look like miniature versions of adult horseshoe crabs. When first entering the sea, they exhibit a 'swimming frenzy' similar to that of newborn sea turtles, swimming vigorously and

continuously for hours. During the larval stage, which can last a year or more, newly hatched horseshoe crabs travel into the ocean water and settle on the sandy bottom in shallow waters. As they develop, they move into deeper waters. After the larval stage, horseshoe crabs move into the juvenile period. The juvenile horseshoe crabs will slowly grow over a period of about ten years. The growing process requires shedding small exterior shells, known as exoskeletons, in exchange for larger shells. Horseshoe crabs can shed up to 17 exoskeletons during development and they can reach 45–50 centimeters from head to tail, while the males grow to approximately 35–40 centimeters.

F.Despite their long history, horseshoe crabs face increased threats in modern times. For this reason, scientists have been studying the populations of horseshoe crabs, but more investigation is needed, particularly on the coast of Florida. A widespread decline in their abundance in the last 20 years may be especially severe in the Indian River Lagoon system in Florida. While the horseshoe crab is not currently listed as threatened, there is rising concern about the fact that it is increasingly absent from the Indian River Lagoon system, where it has historically been common. Loss of the horseshoe crab would negatively impact species that feed on the animal and its eggs and would decrease the biodiversity of the lagoon. Moreover, this development might indicate serious ecological disturbance in the region. In the northeast, the use of horseshoe crabs as bait to catch fish over the past ten years is, in part, responsible for a rapidly declining population of this unique species, and it is suspected that this is also a problem in Florida. However, the extent of this has not been well documented.

Questions 14–18

Reading Passage 2 has six sections A-F. Which section contains the following

information? Write the correct letter, A—F.

NB You may use any letter more than once.

14. a mention of the horseshoe crab's potential value in medical science

Answer: C

Supporting statement: This makes horseshoe crab blood valuable to scientists

Keywords: blood, scientists

Keyword Location: Para C, Line 7

Explanation: According to the text, Enzymes found in horseshoe crab blood are very vulnerable to harmful bacteria and fungi. An additional use of the protein found in the blood of horseshoe crabs is being researched as an antibiotic. All this makes the blood of a horseshoe crab valuable to scientists

15. an explanation of the function of the horseshoe crab's tail

Answer: B

Supporting statement: Horseshoe crabs use it to flip over if they happen to be pushed on their backs,

Keywords: flip over, backs

Keyword Location: Para B, Line 12

Explanation: According to the text, the horseshoe crab uses its tail to flip its body back staring if it gets stuck upside down.

16. a reference to the horseshoe crab's feeding habits

Answer: B

Supporting statement: They can only eat when crawling, as the motion allows them to open and close their mouths. Their diet consists mainly of worms and clams.

Keywords: diet, worms and clams, crawling,

Keyword Location: Para B, Lines 8-9

Explanation: In paragraph B, it is given that worms and clams are the main diet of the horseshoe crab, and they eat their food while crawling, as it allows them to open and close their mouth

17. a description of horseshoe crab reproduction

Answer: D

Supporting statement: The males arrive first and await the females for breeding. Female horseshoe crabs communicate by releasing a scent to signal to the males.

Keywords: breeding, females

Keyword Location: Para D, Line 4

Explanation: The reproduction of horseshoe crabs is described in paragraph D. Arriving first, the males wait for females to mate. In order to communicate with the males, female horseshoe crabs release a smell. After excavating tunnels in the sand, the female horseshoe crabs lay anywhere from 60,000 to 120,000 eggs at a time, which are then covered with sand for protection.

18. an account of the horseshoe crab's development to adulthood

Answer: E

Supporting statement: Horseshoe crabs can shed up to 17 exoskeletons during development and they can reach 45–50 centimeters from head to tail, while the males grow to approximately 35–40 centimeters.

Keywords: exoskeletons, centimeters

Keyword Location: Para E, Lines 10-11

Explanation: Paragraph E, contains the detailed account of the horseshoe crab's development to adulthood. It tells about all the stages a horseshoe crab goes through to finally become an adult crab.

Questions 19 and 20

Choose TWO letter, A - E. According to the writer, which TWO of the following are true about the characteristics of horseshoe crabs?

A. They bury themselves upside down.

B. They must continue moving while eating.

C. They most commonly move by swimming.

D. They are able to replace their missing legs.

E. They breathe through their mouth while on land.

Answer: B

Supporting statement: They can only eat when crawling, as the motion allows them to open and close their mouths.

Keywords: crawling, motion

Keyword Location: Para B, Line 8

Explanation: According to the text, horseshoe crabs can only eat while moving, as it allows them to open and close their mouth.

Answer: D

Supporting statement: What is significant is that horseshoe crabs possess the rare ability to regrow lost limbs.

Keywords: ability, regrow

Keyword Location: Para B, Line 4

Explanation: According to the text, horseshoe crabs can regrow a lost limb if they lose it in any scenario.

Questions 21 & 22

Choose TWO letter, A - E.

According to the writer, in which TWO ways is horseshoe crab blood different from that of most other animals?

A. It has a different mineral composition.

B. It lack a bacteria—fighting protein.

C. Harmless fungi regularly grow in the blood.

D. Its colour changes from blue to red as it circulates.

E. The blood cell carries oxygen to its surface.

Answer: A

Supporting statement: Rather, the blood of horseshoe crabs has a copper-containing protein called hemocyanin.

Keywords: copper, hemocyanin

Keyword Location: Para C, Line 4

Explanation: The text mentions that the horseshoe crabs have a different mineral composition compared to other animals, as their blood has a copper-containing protein called hemocyanin.

Answer: E

Supporting statement: The oxygen is also transported in a fluid on the exterior of the cell, in contrast to most animals,

Keywords: oxygen, exterior

Keyword Location: Para C, Lines 5-6

Explanation: The text mentions that the horseshoe crab's blood cell carries oxygen to its surface in a fluid on the exterior of the cell.

Question 23-26

Choose ONE WORD ONLY for each answer.

A study of the Indian River Lagoon system in Florida has shown a 23…………….. in the

horseshoe crab's population. This means that animals that eat both horseshoe crabs

and their 24………….could also be impacted. The result would affect the Indian River Lagoon system's 25………… Local fishmen taking horseshoe crabs for 26……………..could be one cause of the reduction in numbers.

Answer: DECLINE

Supporting statement: A widespread decline in their abundance in the last 20 years may be especially severe in the Indian River Lagoon system in Florida.

Keywords: 20 years, Lagoon

Keyword Location: Para F, Line 4

Explanation: Over the past two decades, the number of horseshoe crabs has drastically decreased, and this decline may be especially noticeable in Florida's Indian River Lagoon system.

Answer: EGGS

Supporting statement: Loss of the horseshoe crab would negatively impact species that feed on the animal and its eggs

Keywords: species, eggs

Keyword Location: Para F, Lines 7-8

Explanation: According to the text, species that consume horseshoe crabs and their eggs would suffer a great loss if the species disappeared.

Answer: BIODIVERSITY

Supporting statement: and would decrease the biodiversity of the lagoon.

Keywords: decrease, biodiversity

Keyword Location: Para F, Line 8

Explanation: The decreasing number of horseshoe crabs will affect the biodiversity of the lagoon.

Answer: BAIT

Supporting statement: The use of horseshoe crabs as bait to catch fish over the past ten years is, in part, responsible for a rapidly declining population

Keywords: bait, declining

Keyword Location: Para F, Lines 10-11

Explanation: One reason for the decline in the population of the horseshoe crab might be due to the fisherman who uses the crabs as bait to catch fish.

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