Extensive research and fossil evidence suggests that these crinoids lived attached to driftwood, with individuals hanging down into the water column. This scenario is suggested from the observation that fossil Pentacrinites are always found in association with fossil wood and that they are usually only attached to the lower surface. Space would have been at a premium for such a mode of life and this is reflected in that fossil Pentacrinites are usually found in massed clumps. Within these clumps smaller individuals are also found attached to larger individuals rather than the wood itself.
It is thought that the crinoids became fossilised when the logs they relied upon became overloaded and sank into a anoxic mud which preserved them and also retarded their degeneration by bacteria and scavengers. This mode of life is highly unusual for crinoids and is not observed in any modern species.