K-2

Hermit Crab

Implement this lesson:

Use this lesson when discussing animal ecosystems, habitats, or other environmental TEKs. This lesson can be used as part of a larger local theme i.e. Oceans Week. It can also be used for a crab themed day. The duration of this lesson can vary based on student and teacher needs.

Learning Objective:

Students will be able to learn about one of the most common animals found in local saltwater habitats, the hermit crab. They will create an art project using their knowledge.

Texas Essential Knowledge and Skills (TEKS)

Science TEKS

K.10(B) identify basic parts of plants and animals

K.10(A) sort plants and animals into groups based on physical characteristics such as color, size, body covering, or leaf shape

1.9(B) analyze and record examples of interdependence found in various situations such as terrariums and aquariums or pet and caregiver

1.10(A) investigate how the external characteristics of an animal are related to where it lives, how it moves, and what it eats

2.10(A) observe, record, and compare how the physical characteristics and behaviors of animals help them meet their basic needs

2.10(B) observe, record, and compare how the physical characteristics of plants help them meet their basic needs such as stems carry water throughout the plant

2.10(C) investigate and record some of the unique stages that insects such as grasshoppers and butterflies undergo during their life cycle

ELA TEKS

K.3(B) use illustrations and texts the student is able to read or hear to learn or clarify word meanings

K.5(B) generate questions about text before, during, and after reading to deepen understanding and gain information with adult assistance

K.5(E) make connections to personal experiences, ideas in other texts, and society with adult assistance

1.9(D) recognize characteristics and structures of informational text, including: (ii) features and simple graphics to locate or gain information

1.6(C) make and correct or confirm predictions using text features, characteristics of genre, and structures with adult assistance

2.6(B) generate questions about text before, during, and after reading to deepen understanding and gain information

2.6(I) monitor comprehension and make adjustments such as re‐reading, using background knowledge, checking for visual cues, and asking questions when understanding breaks down

Overview

There are several common species of hermit crabs found in the local Corpus Christi area waters. The most commonly found is the thin stripped hermit crab.

Thinstripe Hermit Crab (Clibanarius vittatus)

The Thinstripe Hermit Crab is a small, marine crustacean found along the Gulf of Mexico and Atlantic coast, especially in Texas bays and estuaries. Like all hermit crabs, it has a soft, coiled abdomen that it protects by living inside an empty snail shell.

Appearance and Behavior

Size: up to 3–4 cm (1.5 inches) in body length
Has ten legs, including two large claws (chelae)
Shell is not part of its body—it chooses and lives in a borrowed snail shell
Body is typically dark green or brown with distinct white or pale stripes on its legs
Its name comes from the “thin stripes” seen on its limbs
Moves by dragging its shell along with its legs
Will switch shells as it grows or finds a better fit

Diet and Feeding

An omnivore and scavenger
Eats dead animals, algae, plant matter, and bits of detritus
Helps keep its environment clean by eating decaying material
Forages by crawling over sand, rocks, and seagrass beds

Life Cycle and Reproduction

Reproduces sexually—females carry fertilized eggs under their abdomen
Eggs hatch into free-swimming larvae that drift with plankton
After several molts, they settle on the bottom and begin searching for a shell
Growth continues through molting—shedding old exoskeletons
Needs to find bigger shells to move into as it gets larger

Habitat and Range

Common in shallow waters, especially bays, tidal flats, salt marshes, and seagrass beds
Found along the Gulf of Mexico, especially in Texas, and up the Atlantic coast to North Carolina
Likes warm, brackish waters with access to plenty of empty shells
Often hides under rocks or buries itself in the sand during the day

Conservation Status

Not endangered—considered common and stable
Plays an important role in cleaning the ecosystem
May be affected by:
- Habitat loss due to coastal development
- Pollution and oil spills
- Shell shortages, especially where shells are collected by people

Interesting Facts

Thinstripe Hermit Crabs are social and often seen in groups
May fight or “trade” shells with other hermit crabs
If they outgrow their shell and can’t find a new one, they become very vulnerable
Unlike true crabs, hermit crabs have a curved, soft tail that must stay protected inside a shell
Sometimes carry sea anemones on their shells, which give them protection and get food scraps in return

Possible Books:

A House for a Hermit Crab by Eric Carle
Happy Hermit Crab: A Tale of Shell Seekers by Suzanne Tate
The Three Little Hermit Crabs by Joseph Torcivia
Henry the Curious Hermit Crab by Kathy Kamel
Hermy the Hermit Crab: The Adventure Begins by Andrea Weathers
Don’t Worry Little Crab by Chris Haughton

Procedures:

Introduce hermit crabs by asking what students know about them. Write what students say down in a possible KWL chart.
Watch a video, read a book, or use slideshow to teach students about hermit crabs.
Complete one of the various art projects
Read a book on hermit crabs
Possibly finish KWL chart

Hermit Crab Hand Craft

Paper plate
Red paint
Glitter, paint, markers, etc
White cardstock

Reference Craft

Hermit Crab Maker Space

Seashells
Glue
Maker space materials