Have you ever eaten a crab? Almost everyone knows what a crab looks
like! It has a hard shell, many legs, a pair of pincers. Next time,
look closely at the crab you are eating.
Crabs belong to a group of animals called crustaceans. Other crustaceans
include shrimps and prawns.
Shapes of crabs
The shapes of crabs tell us how they live.
you guess from the its legs how this crab lives?
you guess from its pincers what this crab eats?
crushing pincers: snails and clams
shaped tips: scraping algae
toothed pincers: snagging fishes
delicate pincers: harvesting small bits
is this crab so colourful?
is growing on this crab? Sometimes, swimming crabs have
seaweed and barnacles growing on them. These crabs are usually
infected by parasitic
this a crab dead or alive? No it's not alive. No it's
not dead either! It's just an empty shell! Some fascinating moulting
and other hard-shelled animals moult to get bigger. When they
moult they also regenerate lost limbs.
- The soft-shelled
crab that you eat is a crab that has just moulted.
a crab has just moulted and the skin is still soft, it swallows
water so that the skin hardens to be a little larger. That
is why sometimes when you eat crabs they are watery.
can also only mate when the female has just moulted. So sometimes,
males hold on to a female that is just about to moult so that
he can be the first to mate with her.
can you tell the difference between a dead crab and a moult?
- A moult
has transparent eyes and is light.
- A dead
crab is heavy and smells bad!
are important to the ecosystem
- Like you,
many animals love to eat crabs!
They are an important part of the food chain in the ecosystem.
we think of some animals that might eat a crab? Some charismatic
animals to highlight: otters, shorebirds, other crabs, fishes.
myths to dispel
all crabs can be eaten In
fact, some crabs can be highly poisonous. The poison is not destroyed
even by cooking. Don't eat crabs that you caught yourself from
Finding crabs: Almost every shore will have some sort
of crab. Small ones clamber on rocky shores, others are buried
on sandy shores, while yet more scurry about among seagrasses,
coral rubble and reefs.
Moults are interesting too! These are commonly seen
on the high shore. You can even tell stories about them when
the tide is too high, or while waiting out the wet weather
in a shelter.
Be gentle! Do not poke or prod try to catch crabs.
Try to observe crabs without capturing them. Use a moult to
show parts of the crab.
Beware! Crabs can pinch! Large crabs can give a good
pinch. Don't let small children handle them.