Hydra: Nature's Lava Lamp

[KurtM]

I can spend hours watching slow-motion Hydra. And since I have a good colony going in a mini aquarium at present, the project arose to get a decent image comparing green and brown Hydras. Well, I had a remarkable turn of luck and ended up with a cool picture I want to call "Dancing Partners": three pairs of Hydras, each consisting of one brown and one green. That's picture number 1. As may be seen, green Hydra are smaller and more delicate than brown, but don't let looks deceive you; greens are scrappy little things, and more than hold their own whenever push comes to shove as it sometimes does. Another interesting observation is green & brown have not the least trouble getting along cozily, other than the occasional squabble over a food morsel or perching spot.

Picture 2 is of possible interest since it features guest appearance by Lacrymaria. This is another reason to try a mini aquarium: you never think of something like Lacrymaria (or others, such as Paramecium) as free-swimmers if you only ever see them on wet slides or in dishes. They rotate that wonderful neck of theirs in slow spirals to aid in propulsion, and their bodies are quite round, not flattened.

Number three shows a green Hydra going into sexual reproduction mode, that's what the little whitish bumps and growths on its body are. Normally, these fascinating organisms propagate by budding, but when conditions become harsh, such as scarcity of food or onset of winter, they revert to sexual repro. And sometimes they go there for no apparent reason; it's certainly not too cold in my lab, and I've been feeding them a regular diet of Bosmina (I hope nobody turns me in for Hydra neglect). Incidentally, there are a couple of free-swimming Paramecia near the base of the brown Hydra at right (they show up well in the full rez version).

4 & 5 are just a couple pics I include for no particular reason other than I like them.

[zzffnn]

Fascinating, Kurt! Your photos keep getting better too.

You inspired me to read about hydra on wiki and found that they do not age and can regenerate heads or arms. Wow!

Do you happen to know how soon a hydra can grow back its head or arms, if you cut one in half? I a guessing the injured halves will become a smaller complete individual (without feeding capability in natural environment, it may not be able to expand its size?)

I am just curious. I read that hydra has 3 types of stem cells, the fastest growing (interstitial) type can regenerate in 30 hrs. But what about the entire organism (which probably needs all 3 types of cells?)? A quick Googling did not produce an answer.

[75RR]

Looks like the stars aligned for that first image!

No such thing a too many 'good' Hydra images. Keep them coming.

[Crater Eddie]

Wonderful photos! Always glad to see hydra.
CE

[Hobbyst46]

Applause!

[KurtM]

Fan, don't know the answers to your questions. With such a rich supply I keep wanting to do some experimenting with them, but just don't have the time.