Crayfish
They are also known as crawdads, crawfish, and
freshwater lobsters and are closely related to lobsters,
crabs, and shrimp. There are about 150 crayfish species
in North America and over 540 species global. Crayfish
live in streams, rivers, swamps, ponds, and other
freshwater habitats. Most crayfish are severely aquatic
but some live in semi-aquatic places. The semi-aquatic
crayfish excavate into the soil to get to water (so that
they can breathe).
Body:
The
crayfish has 8 jointed walking legs, a jointed body, 2
pairs of sensory antennae, and compound eyes. It has 2
large tongs or claws called chelipeds.This crustacean
has a firm exoskeleton that protects and supports the
body. If a crayfish loses a leg, the leg will be planted
again physically. The skull and thorax is compound,
forming the cephalothorax. A crayfish breathes oxygen
that is dissolved in water by gills. Their color depends
on diet. Crayfish often molts (loses its old shell and
grows a new one) and It eats the old shell. Crawfish in
North America range from 5-15 cm long.
Food:
Crayfish
eat vegetation, animals, and decomposing organisms. They
are most active at night and eat fish, shrimp, water
plants, worms, insects,
snails, and plankton.
Predators:
Many
animals eat crayfish, such as
fish, herons,
mink,
otters, snakes,
and people.
Label Crayfish External Body
Abdomen
-
The tail area is called abdomen. Attached to the abdomen
are the swimmerets.
Carapace
– It is the defensive shell (exoskeleton)
of the cephalothorax.
Cephalic groove
– It is an indentation between the head
region and the thorax region.
Cephalothoraxes
-
This animal has no neck and it is the combination of
head and thorax. The cephalothoraxes contain the heart,
gills, and stomach.
Cheliped
-
One of two big claws which is used for defense and food
usage.
Eye –
They are located towards the front.
Long antennae - Two long, sensory organs towards the
front of the crayfish.
Stage
- The area above the eyes.
Swimmerets
- Five pairs of short appendages on the stomach which
are used for swimming.
Tail fan
- It is used for backwards swimming.
Telson
- The extension of the tail fan.
Uropods
- Two pairs of appendages on the tail fan
that enclose the telson.
Walking legs
- Four pairs of long, jointed legs used for
walking.
Label
Fiddler Crab
External
Body
Read the definitions below, and then label the fiddler
crab diagram
Antennae
-
Two feelers located towards the face of the crab.
Carapace
– It is the hard, protective external shell
of the crab. The carapace is composed of chitin.
Cheliped
- One of two big claws used for guard and
food handling. In male fiddler crabs, one cheliped is
much bigger than the other; in females, the two
chelipeds are the same size.
Eyestalk - The two complex eyes are located on
eyestalks.
Mouth
- The mouth is located at the front of the
crab, near bottom of the eyestalks and the antennae.
Walking legs - Four pairs of long jointed legs used for
locomotion (walking).
