It has been widely accepted that articulate brachiopod adaptation to and radiation within various benthic environments is reflected in the variability of their attachment organ, the so-called "pedicle". To evaluate how the pedicle functions, the behavior of the terebratulide brachiopod Laqueus rubellus, harvested from Osezaki, Suruga Bay, Japan, was observed for one month in an aquarium. The behavior analysis focused particularly on pedicle movement and its associated muscular system. Anatomical observations of the muscular system demonstrated that the paired dorsal and ventral adjustor muscles are connected to the root of the pedicle via the mantle membrane, and the two muscles of each side cross in an x-shaped configuration. As a result, the pedicle should rotate when either set of adjustor muscles contracts. A succession of such movements would allow the animal to shift its position on the sea bottom while remaining attached to small pieces of debris, such as pebbles or bioclasts. In addition, the twisting and shaking of this brachiopod as a result of multiple successive pedicle rotations has a lifting effect due to the low density of its body compared to the surrounding sediment. Thus, this movement provides a means of avoiding burial. Previous studies of the relationships between benthic fauna and marine environments have indicated that articulate brachiopods can disperse into any benthic environment and attach to whatever debris exists. These studies have also shown that the abundance of articulate brachiopods depends on competition, nutrient supply, and predation pressure. Given the stable nutrient conditions on the sea bottom off Osezaki, competition and/or predation pressure appear to determine whether or not Laqueus rubellus can flourish in this benthic community.