(One video on this page)

This is a picture of a two-headed hydra, created by Cynthia Bruno in Bio 305. Hydra are small freshwater organisms with a sticky foot region to attach to a substrate, a large stomach, and a head end with a ring of tentacles for capturing prey. They are remarkable for their regenerative abilities, and can recover from the most severe traumas. This has allowed analysis of how an organism knows where to make a head, and where to make a foot--the central theme of pattern formation.

To do this manipulation, Cynthia cut a hydra in half along its equator (around the "waist"), and threaded the head end on thin fishing line . She then did the same to another animal, threading it onto the same fishing line but in the opposite orientation (so that both cut ends were facing each other). The two halves healed together (in image above), and she then pushed the two-headed creature off of the fishing line. Two-headed hydra can live for quite some time, feed, and even reproduce asexually.

This is a time-lapse video sequence of Cynthia's two-headed hydra, made one day after she "unthreaded" it from the fishing line. Events are speeded up approximately 48 times.

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