The researchers also made sure that each pair contained one larger snail and one smaller one, since slipper limpets are known to change sex once they reach a certain size. It had previously been proposed that waterborne chemical communication between individuals provided the signal for this transformation to begin, although it now appears that this may not be in the case. At the same time, the smaller snails in these pairs delayed their own development and transformation compared to those in the partitioned pairs. As such, the researchers were reasonably confident that these snails had sufficient access to any vital chemicals released by their fellow limpets that may be involved in prompting the hermaphroditism. By Ben Taub 28 Dec , As a result, the researchers concluded that direct contact, rather than just waterborne chemical communication, may partially mediate the sequential hermaphroditism of slipper limpets. They discovered that the larger snails tended to grow faster and change sex sooner when they were allowed physical contact with other limpets. Smithsonian Tropical Research Institute.