The process of skin tearing and ripping is a form of biomechanics. Researchers have examined this process for the first time and they have discovered a hydra’s cells stretch to in order to split apart, in what is described as a “dramatic deformation.”
Hydra are small, simple marine animals of the phylum Cnidaria and class Hydrozoa. They are native to the temperate and tropical regions. At the mouth opening they have one to 12 thin, mobile tentacles. These tentacles are used to disable and capture prey, such as shrimp, and to draw the food to their mouths. The prey is sucked into the mouth opening. What is peculiar is the how a hydra gets rid of the leftovers; this is not by simply opening of the mouth aperture, but by tearing skin and spitting out the remains. The mouth opening is relatively large to the body of the animal. After this, the organ is once again sealed with body tissue.
The process of ripping open the mouth takes about 60 seconds to complete. To study this, researchers examined one type called Hydra vulgaris. The animals used in the study were genetically modified so that both layers of skin glowed, to allow for easy observation.
The process can be seen in the video below:
It was found the mouth of the creatures opened in a similar way as the pupil of a human eye when exposed to darkness. Here radially oriented fibers in the tissue contract to stretch the cells apart. Furthermore, when the scientists exposed the creatures to muscle relaxants, it was found they were unable to stretch open their mouths.
In a research note, lead scientist Dr. Eva-Maria Collins from the University of California, stated: “The fact that the cells are able to stretch to accommodate the mouth opening, which is sometimes wider than the body, was really astounding. When you watch the shapes of the cells, it looks like even the cell nuclei are deformed.”
The research has been published in the Biophysical Journal, with the paper titled “Dynamics of Mouth Opening in Hydra.”
