The functionality of the eurypterine swimming paddles varied from group to group. In the Eurypteroidea, the paddles were similar in shape to oars. The condition of the joints in their appendages ensured their paddles could only be moved in near-horizontal planes, not upwards or downwards. Some other groups, such as the Pterygotioidea, would not have possessed this condition and were probably able to swim faster. Most eurypterines are generally agreed to have utilized a rowing type of propulsion similar to that of crabs and water beetles. Larger individuals may have been capable of underwater flying (or subaqueous flight) in which the motion and shape of the paddles are enough to generate lift, similar to the swimming of sea turtles and sea lions. This type of movement has a relatively slower acceleration rate than the rowing type, especially since adults have proportionally smaller paddles than juveniles. However, since the larger sizes of adults mean a higher drag coefficient, using this type of propulsion is more energy-efficient.