] Lest anyone think I jest, shipboard rat was seriously part of the diet in Nelson's navy!

Possibly for its efficacy in warding off scurvy? The American Arctic explorer Elisha Kent Kane took to eating shiboard rat (much to the disgust of his crew) when iced in during his 1853 expedition up Smith Sound (between Ellesmere Island and Greenland). Although supplies were low he ate them more for the anti-scorbutic qualities of fresh meat. It worked; he was one of only three men aboard not to be laid low by scurvy.