Is there a mistake in the title of this post? Many people would think so. They think that Sponges are plants and not animals. It would really seem so because sponges stay in one place, and stay attached to an underwater coral or a rock. They don’t have any body parts – as one would expect animals to have some.
Even scientists thought so for a long time until they observed to see how they ate their food – by pulling in the food into their bodies. Sponges come in all shapes and sizes. Some spread over a large area like moss where as some stand upright like trees. Some are really tiny where as some are huge (almost as tall as a person). Some are smooth and soft where as some are hard like a rock. In fact, some are not even spongy they have glass like skeleton. However different they might seem, we can say one thing for sure that the sponges do brighten up the sea life.
A Sponge survives only by breathing water. Wonder if humans could do that too! The body of a sponge made up of cells that move around, but most sponges are still firm, but porous, and the water keeps flowing in and out. Well, the sponge strains the water that passes through its body and selects some nutrients that the water carries. Sponge is not fussy and eat bacteria or some other things that are mixed in the water. However, a few sponge species are known to snack on very small crustaceans in the deep sea.
Some sponges provide a haven for some fish and shrimps that make home inside them. The smarter ones move around the sea by attaching themselves to crab shell, taking a ride as the crab moves. Hmm! Another interesting fact about sponges is some of them can be hermaphrodite. That means that sponges can pretend to be mama sponges or dad sponges whenever they want to. Wow!
Most sponges are not “easy prey”, because they are quite toxic. Animals that eat sponges rarely eat a lot of the same sponge (toxin), but they usually move around “smorgasbording”, so they will not take up too much of the same toxin.
Some of the contents of this post were improved upon suggestions received from Dr. Christine Schoenberg, School of Earth Sciences, The University of Western Australia. Thank you Dr. Schoenberg for helping us improve this in our “Facts for Kids” series