Look very closely at the picture above, can you find the head of this mysterious creature? Well if you can’t, look again because the head is right where the long body meets the tentacles. This animal you just looked at might not be familiar to you; it is called a Brown Hydra. You may have seen this animal before and not even noticed it. The brown hydra is found in ponds, spring brooks, unpolluted streams, rivers, and the littoral zone of lakes. Most Hydra’s are found near the northern hemisphere and parts of Australia.

 

Brown Hydra’s do not just float around, they actually cling to water plants in their habitat, they do this with the end of their body opposite to the end with the tentacles. Now, these small animals may look completely harmless to you, but compared to the smaller animals in which they feed upon, they are quite ferocious. In order to capture their prey, they must paralyze and kill the animal using nematocysts then bring the food to their mouth using their tentacles. Nematocysts are the stinging cells inside all cnidarians have to sting prey or protect themselves. The brown Hydra’s mouth is either star-shaped or circular. The animals they eat are small annelids, copepods, cladocerans, and insects.

 

Hydras are not exactly something you see every day. They are really small, when fully extended they are only 30 mm long! When their bodies are completely extended they almost look like a small piece of string that is frayed at one end, and every time a brown hydra is disturbed, its body contracts making it look like a tiny blob. They range from a greenish color to a brown from surrounding algae. One adaptation this animal has is a small hand like thing that helps it cling on to surrounding rocks and plants In the water. Also, they have nematocysts to protect themselves and to eat. Most animals you see have at least one or two predators, well, lucky for this animal, brown hydras do not have many predators. Also, there is very little known about the population of this animal. I learned a lot about this animal, and a lot of what I learned was really interesting.

 

One thing I learned is that this animal is related to the jellyfish even though it doesn’t exactly look like them, but they both have nematocysts, which shows one of the many characteristics that make them alike. Also, I learned that they grow within ours of the time that they eat. They can be thin at one point, but a couple hours after they eat they grow larger. So, the Brown Hydra is a very small, but very interesting animal.

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Author: Emma H

Publish: 02/2008

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Sources:

www.animaldiverstiu.ummz.umich.edu www.arkive.org www.offwell.htm/com

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Photo Credit:

www.futura-sciences.com/uploads/tx_oxcsfurura/img/hydra_oligactis.JPG