Crustaceans: Diet, Habitat, And All One Wants To Know

black, red and yellow crustacean

A broad collection of arthropods known as crustaceans include lobsters, shrimp, crabs, and even the infamous cockroach. Crustaceans have a robust exoskeleton that both shields them and aids in their movement.

Both freshwater and marine settings contain crustacean, which is significant predators and prey in their respective ecosystems. Scientists and nature lovers find them intriguing research subjects due to their distinctive qualities. In this article, we will educate you about this living organism’s different characteristics and natures.

Table of contents

A little about crustaceans

Most people are unfamiliar with crustaceans and often ask, “What is a crustacean?” Crustaceans fall within the arthropod category. Their bones are outside their bodies, which makes them different from other animals.

Crustaceans are the most varied group of arthropods in terms of variety, and they are the second or third-most numerous group of animals after insects and vertebrates. Crabs and lobsters are among the many crustaceans that dwell in the water. On the other hand, rolie-polys and crayfish are the two varieties found on land.

Their habitats span the Arctic and Antarctic, as well as heights up to 16,000 feet in the Himalayas and below sea level.

In addition to protecting aquatic animal from predators, its strong shell also prevents water loss. However, crustaceans molts as they grow because their exoskeletons do not expand along with the creatures that live inside them.

Until they outgrow them, hermit crabs can be in their head as creatures who carry their “homes” on their backs. Crustaceans usually enlarge their body size immediately following molting by 40% to 80% to fit inside their new exoskeleton.

The appearance

Compared to other arthropods, crustaceans stand out due to their unusual look. Their bodies are coated in a sturdy exoskeleton to sustain and defend them. Chitin and calcium carbonate are the main components of their exoskeleton, which is frequently vividly colored and comes in hues ranging from blue, orange, and yellow to green, brown, and red.

Crustaceans contain several pairs of legs, each specially adapted for a distinct task, such as swimming, crawling, or grasping.

They also have two sizable antennas, which they use to perceive their environment and find food. Crabs are one type of crustacean with pincers or claws to grasp and smash its food. Moreover, species differences in crab appearance include some having streamlined, smooth bodies while others have spiked, rough exoskeletons or both.

All crustaceans, regardless of their appearance, have particular adaptations that help them survive and prosper in their habitats.

Do crustaceans have brains?

The brain, or supraesophageal ganglion, and a ventral nerve cord comprising ganglia, or nerve centers, make up the bulk of the crustacean nervous system.

Crustacean Food

Crustaceans consume tiny creatures, algae, plankton, snails, plants, and even the eggs of other marine species as their diet. They fall in the list of omnivores. Although there are many different types of crustaceans, they all have a wide range of dietary patterns.

Crustaceans are often omnivorous scavengers with a primary job to clean the ocean’s surface. However, primary food source is organic materials that larger predators leaves behind. They consume it while swimming or creeping about.

These water bodies sometimes are not even able to swim around food. A barnacle remains still on a reef and utilize its hairy legs to filter any phytoplankton or zooplankton that passes beneath it. Additionally, these scavenger feed since crustaceans and Nauplius larvae are occasionally found in zooplankton.

Large predatory crustaceans like crabs and lobsters frequently seek and consume other large crustaceans they can catch. During this stage, molting crustaceans are particularly susceptible to being eaten by another species member due to their weakened condition and thin exoskeleton shell.

Furthermore, crabs and other crustaceans use their pincers to eat various food, such as sea urchins, clams, mussels, snails, worms, and many fish.

The Habitat

Crustaceans, a diverse group of arthropods, thrive in a variety of aquatic habitats across the globe. These fascinating creatures actively inhabit oceans, seas, rivers, and freshwater lakes, displaying remarkable adaptability to different environments. From the bustling intertidal zones to the tranquil depths of the ocean, crustaceans can be found scuttling along sandy shores, hiding among vibrant coral reefs, and even dwelling near hydrothermal vents in the ocean floor.

Their active presence in these habitats plays a crucial role in the marine ecosystem, as they contribute to nutrient recycling, serve as prey for numerous predators, and some, like the adorable hermit crab, serve as vital scavengers, enriching the delicate balance of aquatic life.

How do crustaceans hunt?

Due to their variety, crustaceans naturally have a wide range of distinctive feeding strategies. Crustaceans consume their prey directly, filter-feed on their target, scavenge for food or parasitize other organisms.

Although most crustaceans are mobile, and certain motionless species, such as barnacles are immobile. Without a doubt, this affects how they obtain their food. The barnacle is a suspension or filter feeder.

They consume by whisking food from the water into their mouths and do so while using their feet. On the other hand, Rolly pollies use their sense of smell to locate food. They can handle the meal and split it into tiny pieces using their claws, making swallowing easier.

To capture different kinds of prey, they utilize their powerful feet to rip through the shells of other marine animals. You can see that there are almost as many different kinds of crustacean diets as there are different species of crustaceans. However, most species are omnivorous scavengers, happy to eat anything in front of their sharp claws and powerful jaws.

The characteristics of crustaceans

All crustaceans have common traits despite this animal group’s enormous diversity, even if certain species’ morphologies might be challenging to recognize.

These five physical characteristics are present in all crustaceans.

  • Its antennas come in two pairs.
  • A set of mouthparts used for chewing food.
  • On their heads, there are two sets of maxillae.
  • Either oviparous or ovoviviparous crustaceans exist.
  • The two complex eyes of crustaceans are frequently on stalks.

Reproduction of this marine insect

They have sexual development. A small number of species, like barnacles are hermaphrodites and only assume one sex during reproduction. In contrast, most species have distinct sexes. On the other hand, eggs are brooded within the abdominal segments of certain female species.

Depending on the group, some individuals throw their fertilized eggs into the sea, and others tie them to rocks or other nearby items. Some of the lesser-known species are parthenogenetic, which means they generate eggs without the assistance of sperm during sexual reproduction, which typically entails a sperm fusing with an egg.

The first larval stage of nearly all crab species is the Nauplius, which includes a single Nauplius eye and three pairs of appendages that emerge from the animal’s head.

Land crustaceans

A class of arthropods suited to terrestrial conditions are called land crustaceans. They are typically tiny in size and have exoskeleton and segmented bodies like crustaceans, but lack aquatic adaptations. Examples that come to mind are woodlice, hermit crabs, and land crabs. They live in a variety of environments, from tropical forests to deserts, and frequently function as essential scavengers and decomposers in ecosystems. These intriguing critters have successfully transitioned from watery origins to thriving in varied terrestrial habitats by evolving special characteristics to thrive on land.


How many legs do crustaceans have?

They have five joint pairs of legs, and some species have powerful pincers on the front pair of their legs. Crustaceans have two pairs of antennae and complex eyes on stalks to detect predators.

What makes crustaceans unique?

Most crustaceans are aquatic and vary from other arthropods by possessing two pairs of appendages in front of the mouth. They have a pair of appendages that serve as jaws close to the mouth.

Is there any crustacean that tastes with feet?

The odd structure of the lobster, which has yet to undergo many alterations in the previous 100 million years, is well recognized. Its teeth are in its stomach. It has a neurological system in its belly, a brain in its neck, and kidneys in its head. Additionally, it tastes with its feet while hearing with its legs.

Why is it named crustaceans?

The word “crustacea” refers to its rigid, crust-like shell. The shape, appearance, and behavior of crustaceans vary so widely that it is challenging to come up with a description that enumerates characteristics shared by all of them. In particular, this is true of barnacles, which in their mature form, resemble no other crustacean.


A significant subphylum of the Arthropoda family, the crustaceans are frequent food of both humans and animals as food. In addition, there are an estimated 50,000–75,000 species of crustaceans worldwide. Most animal protein consumed by humans comes from these organisms, especially from crabs, shrimp, prawns, lobsters, and other decapods. They play a substantial and sustained role in contemporary art, business, cuisine, geology, economic development, biomedicine, and many other sectors.

Amiri Eliam
I am Amiri Elam I am an expert in the pet food sector. With a deep understanding of animal nutrition and a passion for providing pets with the best possible diet, I am fully equipped to offer advice and guidance on all aspects of pet nutrition. From choosing the right type of food for your pet's specific needs to understanding ingredient labels and ensuring proper portion sizes, my expertise will help you make informed decisions about your pet's diet. By focusing on the latest research and developments in the pet food industry, you can stay up-to-date on the best ways to feed your furry friend and promote their overall health and wellness. can do.