Saturday, August 6, 2011

characteristics of crab and frog


Crabs have one set of claws and four other pairs of legs. If a predator grabs a leg of a crab, the crab will shed it and later it will grow back.
Lined Shore crabs dance sideways down to the sea. They scrape small plants off rocks with the tiny cups on their pincers. The Lined Shore crab hides in the cracks of rocks.
Hermit crabs make their homes in empty snail shells. The hermit crab's back legs hold its shell on tight. The borrowed shells protect their soft bodies. As a hermit crab grows, it needs a bigger shell. Some hermit crabs will try and steal another's shell. They are scavengers who look for dead plants and animals that have fallen to the bottom of the tide pool.
The male crab shoots sperm into two hollows between the females back legs. That will make it possible for the female to lay eggs. When the eggs hatch, they are called zoea larva. The zoea larva feed in the ocean by trapping its food in its bristles. After a while the zoea larva change shape and are called megalopa larva. When the megalopa gets too heavy, it sinks to the bottom of the sea and starts to live as a crab. As the baby crab starts growing, it has to hide because its shell is soft. As it grows, its shell gets harder. Then when the crab gets too big for its shell, the shell cracks and falls off. This is called molting.
DietSome crabs are scavengers and eat dead animals. Some eat plankton. Some young crabs eat worms. Larger crabs eat shrimp and other shellfish.
SizeFrom 1 centimeter to nearly 2 meters
Lined Shore crab - reddish-purpleKelp crab- brown on top, reddish below
Purple Shore crab - dark purple with purple spots on clawsHermit crab - gray-green
Lumpy crab - red-brown Rock crab - light purplish-red
Life CycleCrab eggs hatch into zoea larva which turn into megalopa larva and then into crabs.
Predatorsfish, birds, octopus, and sea otters
Neat FactsA barnacle sometimes gets inside a male crab and takes nourishment from its blood and changes its sex hormones, so the next time it loses its shell it is a female.
TypesLined Shore crab, Spider crab, Kelp crab, Lumpy crab, Pea crabs, Fiddler crab,
Relativesghost shrimp (relative of the Hermit crab)


Frogs have very good eyesight. They bulge out the sides of their heads in order for the frog to see in nearly all directions. Frogs also have amazing sense of hearing. You can often tell the difference between a male and female frog by the size of their eardrum, which can be seen behind their eyes. If the eardrum is smaller than the eye, the frog is a female. On males their eardrum is the same size as the eye.

Frogs have very powerful back legs and webbed feet that help them jump great distances, as well as, swim. Frogs even use their legs to dig, or burrow, underground for hibernating. Certain frogs can jump up to 20 times their own body length in a single leap. Every different species of frog has his or her own look. They come in many colors, patterns and sizes.

Frogs have many predators. Animal predators include birds, fish and reptiles.Most rainforest frogs have pads of sticky hairs on their fingers and toes, as well as, loose sticky skin on their bellies, that make them great climbers to escape their predators. Many of these frogs live in high trees for safety.Other frogs are very good at camouflaging themselves so that they blend in with their environment, making it harder for their enemies to find them. A frog can change the colour of its skin depending on its surroundings.


Many people don’t know the difference between frogs and toads. They are quite different animals, although they belong to the same animal group.


  • Need to live near water
  • Have smooth, moist skin that makes them look “slimy”.
  • Have a narrow body
  • Have higher, rounder, bulgier eyes
  • Have longer hind legs
  • Take long high jumps
  • Have many predators


  • Do not need to live near water to survive
  • Have rough, dry, bumpy skin
  • Have a wider body
  • Have lower, football shaped eyes
  • Have shorter, less powerful hind legs
  • Will run or take small hops rather than jump
  • Do not have many predators. Toad’s skin lets out a bitter taste and smell that burns the eyes and nostrils of its predators, much like a skunk does.