I was sitting on the bank of the river poking around in the water. I flipped over a rock and found all of these flat creatures clinging to the bottom. Once exposed, they immediately began to move around to the other side of the rock. On the top side of the rock, two of them are fleeing and you can see how flat they are. Many of them would detach from the rock once they came back in contact with the water. The current of the river’s edge would gently sweep them away, and then they would slowly sink, reattach to another rock, and move underneath. Every good-sized rock I turned over had a small gathering of them underneath.
I didn’t know what these animals were. I thought they might be some sort of leach. I looked up the photo with a friend at the arboretum and discovered that they were planaria. In the photo, you’ll see that its head is triangular. Not all species have this shape, but if it has this spade-shaped form, then it is definitely a planaria. It can also be identified by its flat body and two eyespots on top of the head. Maybe they are small, but I don’t see any eyespots on these. I will go back and see if I can get a close-up photo.
Planaria are carnivores, feeding on a variety of smaller invertebrates or other small worms. Its mouth is not located on its head, but halfway down its body. It doesn’t have a respiratory system so it lacks lungs or gills. They receive oxygen by diffusion through their body surface. If you think that’s fascinating, check this out. If you cut up a planarian into pieces each piece will regenerate into a new one! I can’t even believe this little creature is real.
