Crustaceans are a type of Arthropod. TheCrustaceans are a type of Arthropod. The
name may not sound familiar, but youname may not sound familiar, but you
probably know them. You may even haveprobably know them. You may even have
eaten one.eaten one.
Where do they live?Where do they live?
They live mostly in the ocean orThey live mostly in the ocean or
other waters. Most commonlyother waters. Most commonly
known crustaceans are theknown crustaceans are the
crab, lobster and barnacle.crab, lobster and barnacle.
What do they look like?What do they look like?
Crustaceans have a hard,Crustaceans have a hard,
external shell which protectsexternal shell which protects
their body. Crustaceans havetheir body. Crustaceans have
a head and abdomen. Thea head and abdomen. The
head has antennae which arehead has antennae which are
part of their sensorypart of their sensory
system. The abdomensystem. The abdomen
includes the heart, digestiveincludes the heart, digestive
system and reproductivesystem and reproductive
The abdomen also hasThe abdomen also has
appendages, such as legs,appendages, such as legs,
for crawling and swimming.for crawling and swimming.
Many crustaceans also haveMany crustaceans also have
claws that help with crawlingclaws that help with crawling
and eating.and eating.
There are about 10,000 different
species of crab. The crab is
native to all of the world's
oceans. There are also
freshwater crabs, and even
some crabs that live on land.
Crabs have a large, hard shell.
The crab has 5 pairs of legs extending from theThe crab has 5 pairs of legs extending from the
side of its shell. The first pair of legs have clawsside of its shell. The first pair of legs have claws
or pincers used to catch and hold food. Theor pincers used to catch and hold food. The
other pairs of legs are used for walking. Mostother pairs of legs are used for walking. Most
crabs don't swim, they use their legs to walk.crabs don't swim, they use their legs to walk.
However, some crabs such as the Blue Crab canHowever, some crabs such as the Blue Crab can
use their legs as paddles to swim.use their legs as paddles to swim.
Lobsters are native to most oceans of the world.
The lobster habitat is rocky, sandy or muddy
ocean bottom and they are generally found
hiding in crevices or in burrows under rocks.
Lobsters have five pairs of legs, the first pair of
legs are claws used to catch and hold food.
Lobsters have a large exoskeleton. As lobsters
grow, the must molt to shed their old
exoskeleton as they grow a larger new shell.
Krill are small crustaceans native to all oceans of the world.
Krill are small shrimp-like creatures usually 1/4 inch to 2 inches in length. Krill
are considered near the bottom of the food chain. They eat phytoplankton,
single-celled plants that float in the seas near the surface.
Krill then become food for fish and other animals that can't eat plants.
They are an important food for sea creatures such as baleen whales,
manta rays, whale sharks, crabeater seals, and a some seabirds.
Most krill travel in large swarms with as many as 10,000 to 60,000 krill
per cubic meter. These dense swarms elicit a feeding frenzy among fish,
birds and mammal predators.
Shrimp are native to
many of the world's
oceans and lakes. They
are generally found in
shallow water. Their
habitat includes both
fresh and salt water.
Although most shrimp
are small, some can
grow up to 9 inches in
length. The shrimp has
a very simple body
consisting of the head
and thorax, and a
muscular abdomin for
swimming. They have
8 pairs of legs, 5 for
swimming and 3 for