Wild Fact #87 – The Carnivorous Sponge – Harp Sponge

Carnivorous Sponge - Harp Sponge

Photo Credit: MBARI

Cool Things About The Harp Sponge

  • The Harp Sponge is slightly different then many other members of their family…they are carnivorous. Yep, a sponge that hunts!
  • This particular sponge is known to grow up to 37 cm (1.2 feet) in length, which may not sound like much but for a sponge, that is pretty spectacular
  • You won’t find the Harp Sponge on your next trip to the beach as these animals typically hang out 11,000 feet beneath the surface of the ocean. In fact, researchers had to use deep sea robots just to discover this predatory sponge

Hooked On Meat

In my opinion the most fascinating aspect about the Harp Sponge has to be their appetite for living living animals.  After all, you don’t typically think of sponges tracking down and consuming living animals (well, other than bacteria and microscopic plankton but that doesn’t really count). So how do they do it? Well, if you look at the picture above  you will notice many long, criss-crossing “stems” (called vanes in fancy science speak) that gives the sponge their harp-like shape. These protruding vanes may look smooth and harmless but in reality they are covered in tiny, velcro-like hooks that will snare any small crustacean (and even some fish) that pass by. Once their snack is snared, they will quickly envelop them in a specialized cavity where the Harp Sponge will break down their prey into smaller, bite-size pieces – after all, you don’t want to choke your dinner.

Harp Sponge

Photo Credit: MBARI

The Grounded Sponge

As you look at the odd harp-like structure, you may be asking yourself what those tiny, white balls are on top of the vanes. Well, besides being a fashion statement those little globules play a major role in the reproductive success of the sponge. Each one of these globules are filled with spermatophores, which the Harp Sponge releases into the open water, with the hope that they will fertilize the spores of another Harp Sponge in the area. So basically, it is how these grounded animals (and I mean grounded in the sense that they actually have a root system holding them in place, not grounded in the sense that they are being punished for missing their curfew) mate with other sponges. Let’s face it, this is a pretty important feature for the long term survival of the species, so please don’t pick the spermatophores.

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