Hydra: Small animal that lives in fresh and clean water
What is it - biological definition
Hydra is a small invertebrate animal that inhabits fresh and clean water. The hydra is part of the Cnidarian phylum and the Hydrozoa class.
Summary of main features:
- They are small, being between 2 and 3 centimeters in length.
- They live in fresh, clean and cold water rivers and lakes. They get stuck in rocks or aquatic plants.
- They inhabit regions of temperate and tropical climate.
- Can be green, gray or brown.
- Hydras have the ability to regenerate. By losing part of her body, she regenerates easily.
- They have tubular and radially symmetrical body.
- Feeds on small aquatic invertebrate animals.
- It has a mouth at the end of the body, from which place thin and moving tentacles.
- They have simple nervous system.
- Hydras can be reproduced in two ways. She can drop eggs into the water, which will then be fertilized. Another way is through germination. A new being is generated in the body of a hydra, which releases it to have its independent life. This second form occurs when food is abundant.
Biological curiosity: origin of the name
- The name was given to this animal in reference to a character from Greek mythology: the Lerna Hydra. According to Greek myths, this monster had three heads. When one of them was cut, two more were born in place.