Think about how often you see rocks every day. Have you ever imagined that one could be alive? Unless you are in Chile or Peru, this probably isn’t the case. But then again, after reading about this creature, you may believe anything is possible.
Pyura chilensis, better known as the living rock, inhabits the Pacific coasts of Chile and Peru. This creature belongs to the Ascidiacea class of non-moving marine invertebrates normally known as “sea squirts.” It eats by inhaling the water surrounding it and filtering the nutritious microalgae in its pharynx, which essentially serves as its mouth. This organ is connected to the animal's digestive tract. After filtering the water, the rock exhales the non-essential fluid once again.
Living rocks belong to the Tunicata subphylum because their outer layers are composed of tunicin, a substance that helps the rocks attach themselves to surfaces where they live. Under this layer is the epidermis, a muscular band, and the main part of the animal.
Living rocks can reside in groups or alone. They are considered a hermaphroditic species because they are born male but develop female functions, too. Since they have both male and female gonads, they can cross-fertilize or reproduce by themselves. Cross-fertilization predominates because it is a more efficacious way to produce offspring, which are small, tadpole-like young that grow into their adult forms after settling on rocks.
The blood of living rocks is clear and has a high quantity of vanadium, which is an extremely rare element. The reason these creatures accumulate such a high quantity of vanadium is unknown. Astoundingly, the concentration of vanadium in their blood can be up to 10 million times that of the seawater around them.
Despite their odd appearance, living rocks are said by some to be delicious. That’s right—people eat them! In Chile, they are fished and locals eat them raw or cooked.
Whether you would be willing to eat them or not, living rocks are fascinating. You may never look at a rock in the same way again.
[Source: Scientific American]