Crustaceans
By Mrs. Hendrie
Crustaceans
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Crustaceans are members of a
large class of animals with
segmented bodies
Crustaceans belong to the same
major division, or phylum, of the
animal kingdom as insects and
spiders
Included among them are lobsters,
shrimp, crabs, wood lice,
barnacles, water fleas, and many
other animals
Lobsters
 Lobsters have teeth-like
structures in their stomach,
which grind partially digested
food. This structure is called the
gastric mill.
 It thrives in cold, shallow waters
where there are many rocks and
other places to hide from
predators
 It feeds on fish, small
crustaceans, and mollusks
Lobsters continued…
 They range from 8 to 24 in n length and 1 to 9 lb in weight,
but have been known to reach lengths of well over 1 yd and
weigh as much as 44 lb, making this the heaviest marine
crustacean in the world.
 An average adult is about 9 inches long and weighs 1.5 to
2 lb
 Main natural predator is the codfish, but other enemies
include haddock, certain species of seals, flounder, and other
lobsters
 American lobsters molt two to three times per year while
young, but only once a year or less often when fully mature,
which is about four to seven years old
 The old shell is often eaten for calcium recovery and the
leftovers are sometimes buried
 More info
http://www.clearwater.ca/media/documents/qa_hardshelllobster.pdf
Diagram of a Lobster
Many Lobsters have eight walking legs and two
large claws (hence the name Decapod-10)
Their swimmerets and tail fin are used for
swimming in the ocean
The larger claw, crusher claw, is used for
crushing its food
Antenna have hairs that are covered with
multiple nerve cells that can detect odors
The larger, thicker hairs are found along the
edges . These hairs control the flow of water,
containing odor molecules, to the inner sensory
hairs
The mouth is also used to push gravel and sand,
and to carry small rocks away
A lobster actually chews its food in its stomach,
rather than its mouth
Crabs
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Male fiddler crabs have one
large claw, which they wave in
the air to impress females and
intimidate other males
If you use some imagination, it
looks like the male is playing a
fiddle, or violin
They feed on a diet comprising
of algae, mollusks, worms, other
crustaceans, fungi, bacteria and
detritus (cord grass)
The teeth of a crab are in its
stomach.
Crabs continued…
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The biggest crab till date was found in Maryland. It
was a male and measured nine inches
After losing its claw, a crab can grow it back
Crabs are also arthropods i.e. they have segmented
appendages, just like a cockroach, butterfly, housefly,
etc.
The male crabs have narrow abdomens, while the
female crabs have broader abdomens (for carrying
eggs)
Diagram of a Crab
 All crabs have eight
walking legs
 As you can see the
fiddler crab has one small
claw and one large claw
 The large claw is for
attracting females and
crushing its food
 The center of its body is
called the carapace
Shrimp
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Shrimp differ from their close relatives,
the lobsters and crabs, in that they are
primarily swimmers rather than crawlers
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The body is covered with a smooth
exoskeleton that must be shed as it grows
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The shrimp's exoskeleton tends to be
thinner than most of the other crustaceans;
it is grayish and almost transparent
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They may grow as long as 9 inches, but
most are smaller
Shrimp continued…
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Shrimp swim forward by paddling their abdominal
swimmerets and can move backward with swift strokes of
their fanlike tails.
A shrimp’s heart is in its head
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They feed on algae and zooplankton
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Diagram of Shrimp
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Decapod with ten jointed
legs on the thorax
Well-developed swimmerets
on the abdominal segments
Pair of antenna
2 Uropods for swimming
1 Telson to steer them in the
water
Carapace which protects
their head
Facts about Crustaceans
The largest kind of crustacean, the giant spider crab of
Japan, measures up to 12 feet across between its
outstretched claws.
The smallest crustaceans are water fleas they are as small
as 1⁄125 inch long
The horseshoe crab is not a true crab, it is more closely
related to scorpions than crabs
Another interesting fact is that you can eat horseshoe
crabs! (there isn’t much meat)
Barnacles are a delicacy in parts of Europe and South
America. Crayfish are a centerpiece of spicy Creole and
Cajun cuisines of Louisiana.
Other fun facts go to
http://www.hightechscience.org/funfacts.htm
Comparing Crustaceans
Lobster
Crab
Shrimp
Large claw to crush
their prey
Large claw to crush
their prey and attract
females
No claws
crawler
crawler
swimmer
Heart in
abdomen
Heart in
carapace
Heart in its
head (carapace)
Molt
antenna
Decapod
swimmerets
Molt
antenna
Decapod
swimmerets
Molt
antenna
Decapod
swimmerets
Work Cited
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http://www.buzzle.com/articles/what-do-shrimp-eat.html
http://www.clearwater.ca/media/documents/qa_hardshelllobste
r.pdf
 http://www.dnr.sc.gov/marine/pub/seascience/images/shrimpp
artslg.gif
 http://education.yahoo.com/reference/encyclopedia/entry/shri
mp
 http://www.enchantedlearning.com/subjects/invertebrates/crust
acean/label/fiddlercrab/answers.GIF
 http://www.gma.org/lobsters/lobsterbottomview.gif
 http://www.Howstuffworks.com
 http://lifestyle.iloveindia.com/lounge/facts-about-crab1884.html
Work Cited continued…
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http://www.nefsc.noaa.gov/faq/
http://www.planetinverts.com/cardinal_shrimp/cardinal_shrimp_web3.jpg
http://thesociallens.files.wordpress.com/2009/05/full-size_blue-crab.jpg
http://www.science.unsw.edu.au/media/pics/site/imagecache/CF835EA7C3
B6CA4EB835093D23ED7F55.jpg
http://www.windvd.org/resources.php?artid=227