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Index of Subjects Hi Jim, Electroreceptors in SN moles? Only in water are electroreceptor systems believed to be usable at all, because only in water can significant external gradients of voltage exist around an animal, although these gradients are still really tiny (a few microvolts per centimeter). Air is such a good insulator that virtually no loops of muscle current escape from the body that could be detected externally, in air. This is unlike the situation in water where electric fields can and do develop around the animal, mostly arising from its muscle activity, and is even used in active signalling in some groups. So not out of the question in principle in these moles if they use their tentacles in water or wet soil, and apparently they do normally live in a partly wet environment. The star tentacles are known to be touch-sensitive with a high density of mechanoreceptors -- but then electroreceptors elsewhere are believed to have evolved from mechanoreceptor cells. According to Ted Bullock, electroreception probably evolved independently at least six times in fish and is mostly confined to that group, but also is present in platypus and perhaps even in a dolphin. So, a resounding 'maybe'... Steve, Halifax Quoting "James W. Wolford" <jimwolford@eastlink.ca>: P.S. Those 22? tentacle-like feelers making up the nose are extremely > sensory, allowing the moles to catch prey in situations with low or > no light, and, if memory serves, the tentacles are also known to be > electro-sensory (as are bottom-feeding sharks and skates?), so that > they can sense the metabolic electricity of the prey animals...
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