Water Bear

Echiniscis (genus)

There are over 100 species in this genus. They are very difficult to tell apart.

Water Bears are tiny animals you need a microscope to see. They live in mosses, lichens, and liverworts. A few species live on plants in fresh water.

Water Bears have eight legs with four claws on each. They have short, stout bodies in the shape of a cylinder.

The mouths of Water Bears have sharp pointy objects, called stylets. They use their stylets to cut into moss leaves or algae, their main foods. Then they suck the juices from the plant.

Water Bears sometimes eat tiny animals called nematodes and rotifers that also live in moss.

Water Bears have developed an interesting way to survive if the moss they live in dries up. It is called an "antibiotic state." Since they need moisture to live, if a moss dries up, the Water Bear becomes inactive, almost like a hibernation. It mostly dries up also. Then, when the moss becomes wet again, so does the Water Bear. It revives, and goes on with its life.

Sometimes, Water Bears can be in an antiobiotic state for several years.

There are more female Water Bears than males. The females are also slightly larger.

After mating, females lay eggs in a shed exoskeleton. Water Bears molt (shed their exoskeletons) just like insects and crayfish. Young Water Bears must molt several times before they are adults.

Water Bears can be different colors, depending on the species, including gray, bluish, yellowish-brown, reddish, and brown.

Water Bears are not Arachnids, even though they have eight legs like spiders and ticks. They are also not Nematodes or Crustaceans, even though they have things in common with those groups of animals. Water Bears get their own phylum, called Tardigrada, because they do not fit in with another group of animals.

Additional Media

Description
Type
Credit
Water Bear
Video
Nikon Microscopy U
Download Quicktime if you are unable to play video.

Relationships in Nature:

PREY/FOOD
PREDATORS
SHELTER
OTHER

White Cushion Moss

Predatory Nematode

White Cushion Moss

Predatory Nematode

Green Algae

Rotifer

Common Greenshield

Green Algae

British Soldiers

Relationship to Humans:

Water Bears do not seem to really help or hurt people. They spend all their time in mosses, lichens, and water. They do help with eating and breaking down these plants.

KINGDOM
Animal
PHYLUM
Tardigrada
CLASS
Heterotardigrada
ORDER
Echiniscoidea
FAMILY
Echiniscidae
GENUS
Echiniscis
SPECIES
Echiniscis (many species)

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