mercow

Etymology

From mer- + cow, modelled after sea-cow.

noun

Any of several marine mammals of the order Sirenia, including the manatee and dugong; sea-cow.“Ma ruffled my crew cut. "If you'd been the lookout, you'd've told them these were sea cows, not mermaids, right?" "Right," I said. "Mercows," said Mr. Drake behind us. "Moo. Glub glub glub. Moo."”