|
|
|
The Japanese Spider Crab - The World's Biggest Arthropod! |
|
|
What is the Japanese Spider Crab?
The
world largest arthropod is the Japanese Spider Crab. They are
called spider crab because their long thin legs make them look like
spiders! You can see a picture of one here.
The Japanese Spider Crab
is the World's Largest Crustacean and Arthropod. This photo was taken
at the
Singapore Underwater World in Sentosa Island
The Japanese
Spider Crab can weigh up to 20kg (44 lb) and, when fully streatched
out, can measure 4 metres (13 feet) from the tip of one leg to the
other! Their body is small compared with their legs, but can still
reach 60cm (2 feet). They have 10 legs - the front two legs
are used as
claws for feeding. Although it is the world's biggest Crustacean, it is
not the world's heaviest - the American Lobster weighs more.
Where does the Japanese Spider Crab Live?
The Japanese Spider Crab is found in the Pacific Ocean around Japan.
They spend most of their time living under water - they can live in
water as deep as 200-300m (220-330 yards). They
can live up to 100 years old. They have orange body with white
spots on their thin legs. Their eyes are situated on the
front, and
two thorns stick out between them. During the spring time they lay eggs
in waters as
shallow as 50 m (165 feet). They eat plants, algae, and small
fish. Their long legs help
them to move quickly to catch their prey.
What is a Spider Crab?
There are about 700 types of Spider Crab in the world - they have
shells with a point at the front, and often have long legs. These are
about 10% of the know species of Crab - scientists call them Brachyura, which
means "short tail". Crabs are crustaceans with only a short tail or
none at all. The crabs are grouped together with lobsters and shrimp
into a group called Decapods
(ten feet), and then again into a larger group of crustaceans with
about 22000 species. Surprisingly, this larger groups name (Malacostrata)
actually means "soft shell"! Malacostrata are Crustaceans, and the
Crustaceans are grouped together with spiders, insects, millipedes and
scorpions into a phylum called the Arthropods.
So, the Japanese Spider Crab, as well as being the world's largest
Arthropod, is also
- The world's largest Crustacean,
- The world's largest Malacostrata,
- The world's largest Decapod,
- The world's largest and heaviest Crab, and
- The world's largest and heaviest Spider Crab
It's not the heaviest Arthropod, Crustacean or Decapod - that honor
goes to the stocky American Lobster, which outweighs the Japanese
Spider Crab by 2kg (4.5 lb).
Japanese Spider Crabs and Humans.
People eat Japanese Spider Crabs. They are considered a delicacy in
various parts of Japan, where it is salted and steamed. Unfortunately,
in some parts, people have caught too many, and the numbers of Japanese
Spider Crabs is dropping. Now, there are some efforts to protect the
Japanese SPider Crab so it doesn't die out completey - for
example, fishermen are not allowed to catch them
during the spring, when they lay their eggs. Japanese Spider Crabs are
very gentle, and are popular in large aquaria.
|
|
Who's Online
We have 38 guests online
|