Haplosclerids are distributed worldwide, even in freshwater. They stand out as sponges that can tolerate an unstable home environment. You find them in places like estuaries that suffer regular changes in salinity and water levels, tropical marshes that dry up in summer, and high elevation lakes that freeze in winter. How can a sponge survive these fluctuating environments Haploscerids usually alternate between sexual and asexual reproduction, and can go asexual when conditions are bad. They produce buds made of cells and a food supply called gemmules, which are little miracle packets that can survive freezing and drying. If it gets too dry, gemmules go into a torpid state called estivation and, if it gets too cold, they hibernate. The adult sponge may die, but leave behind a bunch of gemmules that can wait and begin to grow again when conditions improve.

Sponges do not move around much; they are considered to be sessile or fixed in one place. However, research has shown that some sponges can move slowly by shifting their cells in a coordinated fashion. They can reshape themselves to crawl along the seafloor or other surface. They extend parts of their bodies and contract others to achieve locomotion. However, if you attempt to watch a sponge moving, you will likely be disappointed. At best, they move tiny distances, like a couple of millimeters per day. Juvenile sponges are much more mobile. A sponge larva is a little ball of cells with hair-like extensions (cilia or flagella) that allow it to paddle around for a few days until it finds a place to settle down. Once settled, its cells transform to be more appropriate for a sessile organism.