Water Bears at Hastings!
Never heard of a water bear? Well, they are very small, and very, very peculiar animals. Dr. Carl Johansson, from Fresno City College, spent some time at Hastings in late May, collecting water bears. Carl and crew have that rare sense of appreciation for these tiny "water bears". They are distinct enough to have earned placement by some in their own Phylum. How so? They require a good dissecting microscope to see, appear to be related to arthropods, are cute as buttons, but can be dried out entirely and not die. This "cryptobiotic state" allows them to get through the dry California summers. During the winters, they bob around in mosses, under lichens and in cracks of rocks, shingles, and detritus. They are clumsy, creep awkwardly and their muscles are made of only one or a few cells. They bound around, putting food in a mouth where it enters a relatively typical invertebrate gut. Muscles are connected to an exoskeleton (dark lines in the sketch). They twitch the muscles that are attached to plates in their exoskeletons. They can bend and move their feet awkwardly. Some can live in salt water, but most need fresh water, or at least damp lichen. They have no lungs or gills; they must get oxygen through their skin. They make eggs that are often used by experts to identify different species. Most species lay 2-6 eggs. A pile of tardigrade eggs would be a small nest indeed. Dr. Johansson kindly provided a photo of California tardigrade, Hypsibius oberhaeuseri, which is shown as a photo through a microscope (below). You never know; these little guys could be bouncing all over that lichen growing on your roof!