so that odorant molecules in the air bubbles are wafted over the olfactory receptors. The speed of the bubbles is compared to other mole's speed of sniffing. Scientists found that the bubbles are being blown towards targets such as food. Before the star-nosed mole, scientists did not believe that mammals could smell underwater, let alone smell by blowing bubbles. In 1993, Edwin Gould and colleagues proposed that the star-like proboscis had electroreceptors and that the mole was therefore able to sense the electrical field of its prey prior to mechanical inspection by its appendages. Through behavioral experiments, they demonstrated that moles preferred an artificial worm with the simulated electrical field of a live earthworm to an identical arrangement without the electrical field. They suggested, therefore, that the nerve endings in the star’s tentacles are indeed electroreceptors and that the moles move them around constantly to sample the strength of the electromagnetic field at different locations as they search for prey. However, the hypothesis remains unexplained physiologically and has not yet been accepted by the scientific community. Instead, the hypothesis proposed by Catania, in which the function of the appendage is purely tactile, seems to be more feasible and is the one currently accepted. Evolution The development of the star-like appendages suggests precursors with proto-appendages on an ancestor's snout, which became elevated over successive generations. Although this theory lacks fossil evidence or supporting comparative data, nearly all extant moles have sheets of the Eimer’s organ making up the epidermis of their snout around the nares. Also, recent studies of Catania and colleagues identified one North American species (Scapanus townsendii) with a set of proto-appendages extending caudally on the snout which exhibit a striking resemblance to the embryonic stages of the star-nosed mole, although Scapanus townsendii has only eight subdivisions on its face, rather than the 22 appendages found on the star-nosed mole. Such change is of common occurrence in evolution and is explained by the advantage of efficiently adding modules to the body plan without need to reinvent the regulatory elements which produce each module. Thus, although the star is unique in its shape and size, it seems feasible that the structure is based on a more ancestral bauplan as it comprises similarities found in a wide range of other moles and also in the molecular structure of other mammals. The picture which emerges suggests that the star-nosed mole is an