Soak In These Facts
Sunday
Though early zoologists leaned plant-y, we now know that sponges are animals, albeit without muscles, organs, or specialized tissues, and may have indeed been the first multicellular animals ever.
Monday
Most sponges are filter feeders and create the water currents that bring in the plankton, bacteria, viruses, and detritus which sustain them. Not all sponges, however, are so passive. Some species insert tentacles into living hosts to feed off of them, and others bore holes into their hosts to eat. Sponges living where there is very little biological matter to eat go very retro, digesting the 1000+ year-old fossilized remains of invertebrates from the ocean floor.
Tuesday
As sponges eat, so too are they eaten. “Spongivore” animals specialize in eating…sponges. Most are sea slugs, but several fish, nudibranchs, and the Hawksbill turtle also join the feast.
Wednesday
Sponges can completely regenerate themselves, not just to repair damage, but from single cells taken from the original sponge. No other plant or animal can regenerate to this extent.
Wednesday
Humans have been using real sponges to bathe and clean for the last 3,000 years, but artificial sponges arrived in about in the 1940s. They are far more common in households today than the real thing, and are typically made of cellulose and polymers.
Friday
When it comes to reproduction, sponges can have it both ways (sexual and asexual reproduction, that is). Some sponges reproduce alone simply by shedding parts of themselves, as described above, budding, or releasing gemules into the water to grow later. Some species are hermaphroditic, producing sperm and eggs, but these are produced at different times so as to avoid self-fertilization. Notably, this sperm can sometimes be released in dense “clouds” in the water, not unlike mushrooms releasing their spores in visible puffs (see Friday, week of 1/21/2024).
Saturday
That sponge in your shower does not hint at how big they can grow in the ocean depths. At 7 x 12 feet, a sponge “the size of a minivan” has been discovered in Hawai’i, and the aptly-named barrel sponge reaches sizes of at least 6 feet across.