Animal Nature Study by Various Animal Nature Study by Various    

Lesson 34: The Crayfish

Performer: LibriVox - Kathy Wright


'Two Little Crayfishes Quarrel' from Among the Pond People by Clara Dillingham Pierson

The day after the Eels left, the pond people talked of nothing else. It was not that they were so much missed, for the Eels, you know, do not swim around in the daytime. They lie quietly in the mud and sleep or talk. It is only at night that they are really lively. Still, as the Mother Mud Turtle said, "They had known that they were there, and the mud seemed empty without them."

The larger people had been sorry to have them go, and some of them felt that without the Eels awake and stirring, the pond was hardly a safe place at night.

"I think it is a good deal safer," remarked a Minnow, who usually said what she thought. "I have always believed that the Eels knew what became of some of my brothers and sisters, although, of course, I do not know."

"Why didn't you ask them?" said a Stickleback.

"Why?" replied the Minnow. "If I had gone to the Eels and asked them that, my other brothers and sisters would soon be wondering what had become of me."

"I have heard some strange things about the Eels myself," said the Stickleback, "but I have never felt much afraid of them. I suppose I am braver because I wear so many of my bones on the outside."

Just then a Wise Old Crayfish came along walking sidewise. "What do you think about the Eels?" asked the Stickleback, turning suddenly to him.

The Crayfish stuck his tail into the mud. He often did this when he was surprised. It seemed to help him think. When he had thought for awhile, he waved his big pinching-claws and said, "It would be better for me not to tell what I think. I used to live near them."

This showed that the Wise Old Crayfish had been well brought up, and knew he should not say unpleasant things about people if he could help it. When there was need of it, he could tell unpleasant truths, and indeed that very evening he did say what he thought of the Eels. That was when he was teaching some young Crayfishes, his pupils. Their mother had brought up a large family, and was not strong. She had just cast the shell which she had worn for a year, and now she was weak and helpless until the new one should harden on her. "It is such a bother," she said, "to keep changing one's shell in this way, but it is a comfort to think that the new one will last a year when I do get it."

While their mother was so weak, the Wise Old Crayfish amused the children, and taught them things which all Crayfishes should know. Every evening they gathered around him, some of them swimming to him, some walked forward, some sidewise, and some backward. It made no difference to them which way they came. They were restless pupils, and their teacher could not keep them from looking behind them. Each one had so many eyes that he could look at the teacher with a few, and at the other little Crayfishes with a few more, and still have a good many eyes left with which to watch the Tadpoles. These eyes were arranged in two big bunches, and, unless you looked very closely, you might think that they had only two eyes apiece. They had good ears, and there were also fine smelling-bristles growing from their heads. The Wise Old Crayfish sometimes said that each of his pupils should sit in a circle of six teachers, so that he might be taught on all sides at once.

"That is the way in which children should learn," he said, "all around at once. But I do the best I can, and I at least teach one side of each."

This evening the Wise Old Crayfish was very sleepy. There had been so much talking and excitement during the day that he had not slept so much as usual; and now, when he should have been wide awake, he felt exceedingly dull and stupid. When he tried to walk, his eight legs stumbled over each other, and the weak way in which he waved his pinching-claw legs showed how tired he was.

After he had told his pupils the best way to hold their food with their pinching-claws, and had explained to them how it was chewed by the teeth in their stomachs, one mischievous little fellow called out, "I want to know about the Eels. My mother would never let me go near them, and now they've moved away, and I won't ever see them, and I think it's just horrid."

"Eels, my children," said their teacher, "are long, slender, sharp-nosed, slippery people, with a fringe of fins along their backs, and another fringe along their bellies. They breathe through very small gill-openings in the backs of their heads. They have large mouths, and teeth in their mouths, and they are always sticking out their lower jaws."

"And how do—" began the Biggest Little Crayfish.

"Ask me that tomorrow," said their teacher, stretching his eight walking legs and his two pinching-claw legs and his tail paddles, "but remember this one thing:—if you ever see an Eel, get out of his way. Don't stop to look at him."

"We won't," said one little Crayfish, who thought it smart to be saucy. "We'll look to stop at him." All of which meant nothing at all and was only said to annoy his teacher.

They scrambled away over the pond-bottom, upsetting Snails, jiggling the young Clams, and racing with each other where the bottom was smooth. "Beat you running backward!" cried the Saucy Crayfish to the Biggest Little Crayfish, and they scampered along backward in the moonlit water. There was an old log on the bottom of the pond, and they sat on that to rest. The Biggest Little Crayfish had beaten. "I would like to see an Eel," he said.

"I'd like to see them running on the land," said the saucy one.

"Pooh!" said the biggest one. "That's all you know! They don't run on land."

"Well, I guess they do," replied the saucy one. "I know as much about it as you do!"

"Eels swim. They don't run," said the biggest one. "Guess I know!"

"Well, they don't swim in air," said the saucy one. "That's the stuff that lies on top of the water and the ground, and people can't swim in it. So there!"

"Well, I've seen the Wild Ducks swim in it! They swim with their legs in the water, and with their wings in the air," said the biggest one.

"I don't believe it," said the saucy one. "Anyhow, Eels run on land."

"Eels swim on land," said the biggest one.

"Eels run!"

"Eels swim!"

"Run!"

"Swim!"

Then the two little Crayfishes, who had been talking louder and louder and becoming more and more angry, glared at each other, and jerked their feelers, and waved their pinching-claws in a very, very ugly way.

They did not notice a great green and yellow person swimming gently toward them, and they did not know that the Eels had come back to live in the old pond again. Mother Eel opened her big mouth very wide. "On land," she said decidedly, as she swallowed the Biggest Little Crayfish, "Eels wriggle." Then she swallowed the saucy one.

"There!" said she. "I've stopped that dreadful quarrel." And she looked around with a satisfied smile.

    Animal Nature Study by Various Animal Nature Study by Various    

Lesson 34: The Crayfish

Performer: LibriVox - Kathy Wright

Directions

Study the lesson for one week.

Over the week:

  • Read the story.
  • Review the animal synopsis.
  • Study the vocabulary words.
  • Learn the concepts.
  • Complete the enrichment activities.
  • Study the review questions.

Synopsis

This lesson introduces crayfish, which are in a new group of animals called crustaceans. Crayfish are notable for the magnificent pair of nippers on each of the front legs. Like a thumb and finger, the thumb joint can move back and forth freely. The nippers are edged with saw teeth and armed with a sharp claw at the tip for capturing prey and fighting. Crayfish have five pairs of legs. The second and third pairs have nippers like the first, and the fourth and fifth pairs have only a single claw. Crayfish have two compound eyes set on extendable stalks that can be swiveled in any direction to look for danger. Crayfish breathe oxygen from water using the gills on their legs. Crayfish have long, segmented antennae that are thick at their base and thin at the threadlike tips. Above the antennae on each side is a pair of shorter ones called antennules. The antennae and antennules are used for sensing the environment around the crayfish. Crayfish have a cephalothorax, six abdominal segments, and a flaring tail. The tail can be opened and closed like a fan; it can be lifted up or curled beneath. The abdomen has some very beautiful feather-like organs called swimmerets that, along with the tail, help propel the crayfish through the water. In the spring, the mother crayfish covers the swimmerets with glue and plasters on the grapelike clusters of eggs she lays. Even after the little ones hatch, they remain clinging to the maternal swimmerets until they are large enough to scuttle around on the brook bottom and look out for themselves. Crayfish haunt ponds and still pools along brooks and rivers. There they hide beneath sticks and stones, or in caves of their own making. Crayfish are omnivorous, eating both plants and small animals such as worms and fish.

Vocabulary

Compound Eye: An eye consisting of an array of numerous small visual units, as found in insects and crustaceans.
Gill: The paired respiratory organ of fishes and some amphibians, by which oxygen is extracted from water flowing over surfaces.
Antennules: A small antenna, especially either of the first pair of antennae in a crustacean.
Cephalothorax: The fused head and thorax of spiders and other chelicerate arthropods.
Swimmerets: A forked swimming limb of a crustacean, five pairs of which are typically attached to the abdomen.

Concepts

Facts about crustaceans:

  1. Crustaceans include shrimp, lobsters, woodlice, hermit crabs, and barnacles.
  2. Crustaceans do not have bones. They have an exoskeleton. To grow larger, they shed, or molt their exoskeleton and grow a new one.
  3. Crustaceans have two pairs of antennae.
  4. Crustaceans have jointed appendages to enable movement.
  5. Most, but not all crustaceans live in the water.

See a picture of an aquatic shrimp below.

See a picture of land-living woodlice below.

Enrichment

Activity 1: Narrate the Story

  • After reading or listening to the story, narrate the story events aloud using your own words.

Activity 2: Watch the Video

  • Watch the online video, and observe some crayfish.
  • Look for their claws and segmented legs.

Activity 3: Classify the Animal

  • Crayfish are animals, invertebrates, arthropods, and crustaceans.
  • Trace which categories crayfish fit into on the classification chart.

Activity 4: Color and Label a Crayfish   

  • Click the crayon above. Complete page 70 of 'Science Field Book for Second Grade.'

Activity 5: Take a Nature Walk

Take a nature walk, locate a crayfish or other animal to observe, gather data and notes, and use that information to create a field book entry. You may wish to take a pencil and a small notebook to jot down sketches and observations. If you can't find a crayfish, you might make a sketch based on the video in Activity 2.

Before you take the nature walk, review:

  • The field book template you'll later complete on page 71 of 'Science Field Book for Second Grade.'
  • The suggested list of observations below.

Behavioral observations include:

  • How does the crayfish move?
  • How does the crayfish eat?
  • What does the crayfish eat?
  • How does the crayfish sense the world?

Habitat observations include:

  • Does the animal live in a forest, a field, a town, or near water?
  • In what type of climate does the animal live (e.g. temperate, tropical, arid, arctic)?
  • In what type of house does the animal live?

Appearance observations include:

  • What colors are the wings and body?
  • How many legs does it have?
  • How many antennae does it have?

Activity 6: Complete a Field Book Entry   

  • Click the crayon above. After your nature walk, complete page 71 of 'Science Field Book for Second Grade.'

Review

Question 1

For what do crayfish use their great front nippers?
1 / 6

Answer 1

Crayfish use their great front nippers for catching prey and defending themselves.
1 / 6

Question 2

What do crayfish eat?
2 / 6

Answer 2

Crayfish plants and small animals such as fish and worms.
2 / 6

Question 3

Do crayfish have bones?
3 / 6

Answer 3

Crayfish do not have bones. Instead, they have exoskeletons.
3 / 6

Question 4

What happens to the exoskeleton as crayfish grow larger?
4 / 6

Answer 4

Crayfish molt, or shed, their exoskeletons and grow new ones as they get larger.
4 / 6

Question 5

Of what use are swimmerets to crayfish?
5 / 6

Answer 5

Crayfish use their swimmerets to locomote through the water. Mother crayfish glue their eggs to the swimmerets. Even after hatching, the baby crayfish remain clinging to the maternal swimmerets until they are large enough to move on their own.
5 / 6

Question 6

How many legs do crayfish have?
6 / 6

Answer 6

Crayfish have ten legs.
6 / 6

  1. For what do crayfish use their great front nippers? Crayfish use their great front nippers for catching prey and defending themselves.
  2. What do crayfish eat? Crayfish plants and small animals such as fish and worms.
  3. Do crayfish have bones? Crayfish do not have bones. Instead, they have exoskeletons.
  4. What happens to the exoskeleton as crayfish grow larger? Crayfish molt, or shed, their exoskeletons and grow new ones as they get larger.
  5. Of what use are swimmerets to crayfish? Crayfish use their swimmerets to locomote through the water. Mother crayfish glue their eggs to the swimmerets. Even after hatching, the baby crayfish remain clinging to the maternal swimmerets until they are large enough to move on their own.
  6. How many legs do crayfish have? Crayfish have ten legs.

References

  1. Comstock, Anna Botsford. Handbook of nature-study (Twenty-fourth edition). Ithaca, New York Comstock Publishing Company, Inc, 1911.
  2. 'Crayfish.' Wikipedia. Wikipedia.org. n.p.
  3. 'Crustacean.' Wikipedia. Wikipedia.org. n.p.