It seems scary but so cute actually: Crawfish

I said before I'll introduce you to some animals or plants from sea or freshwaters. This post's subject is about crawfish (or crayfish).

Crayfish, often referred to as crawfish or crawdad, are freshwater crustaceans resembling small lobsters, to which they are closely related. They breathe through gills and are found in bodies of fresh water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is fresh water running, and which have shelter against predators. Most crayfish cannot tolerate polluted water, although some species such as the invasive Procambarus clarkii are more hardy. Some crayfish have been found living as much as 3 m(10 feet) underground.

Color and size varies with species, diet, and age. Most are red, some are green, brown, tan, or blue with black or orange markings in various combinations. Often juveniles will be a light tan color that turns to a deep red as an adult. The coloration depends in part on their diet, and can change with a change in diet. Adult size is 2" to 6" for most US species. Some Australian varieties can be much larger.

Crayfish also need to moult as they grow because their hard exoskeletons do not allow much room for expansion. Baby crayfish can moult on a daily basis but as they grow older, the regularity of moults decreases to a period of weeks or even months. The first few days after a moult, a crayfish's skin is very soft and it is very vulnerable to attacks from other animals and crayfish. The early signs of moulting include lack of appetite and a slow down in activity. During this period the crayfish ingests calcium into an internal organ, not into the exoskeleton.

When the crayfish is ready to moult, it will try to find a hiding spot. Then it will move onto its back and begin fanning its pincers, legs and swimmerets (under the tail) in order to get as much oxygen as possible. The carapace will begin to crack behind the head; the new appendages then pierce the old shell; and then after about five minutes, a sudden, violent movement will detach the old shell from the crayfish.

In the next post I'll tell everything that I know about Procambarus clarkii

resources: wikipedia and anapsid.org

pic1 (top-right): fws.gov, pic 2 (top-left): photos.dusac.org