No. 45: May-Jun 1986
The bill of the duck-billed platypus has always looked kind of dumb -- as if Nature flushed with her success with polar bears (below) got careless when designing the platypus! How ignorant we were of Nature's genius. The platypus didn't borrow its snout from ducks but rather from the electric fishes.
"That evolutionary enigma, the duckbilled platypus, has more than its egglaying to distinguish it from other mammals. It now appears that in common with some species of fish and amphibians, it can detect weak electric fields (of a few hundred microvolts or less). Not only that, but it uses its electric sense to locate its prey, picking up the tiny electrical signals passing between nerves and muscles in the tail of a shrimp."
(Anonymous; "The Battery-Operated Duck-Billed Platypus," New Scientist, p. 25, February 13, 1986.)
Reference. Mammal electrosensitivity is cataloged under BMO8 in Biological Anomalies: Mammals II. This catalog is described here.