This got me thinking on the theme of animal expressions that don't work in other dialects because the animal isn't native to other dialect's area. I'm finding it easier to think of AmE expressions that don't translate into BrE. For instance, while the hedgehog is a native species in Britain, there don't seem to be any hedgehog-based clichés. So, I'm going to cheat a little and offer pissed/drunk/tight as a newt, meaning 'extremely intoxicated'. There are newts in America, but (a) they are different genera than the newts in Britain and (b) salamander is, in my experience, the more common way of referring to them in AmE. (But this may differ in parts of the US with different kinds of newts.) According to Red Herrings and White Elephants by Albert Jack, the newts in pissed as a newt weren't originally animals, but young men who were hired to watch gentlemen's horses while they were out on the town. The gentlemen would return from their libations to find that the "newts" had tippled too. However, there's no record of this sense of newt in the OED and Partridge's Concise Dictionary of Slang and Unconventional English says the phrase probably comes from Army officers' slang. Is Albert Jack a quack? (For some clues as to the answer to this question, see Arnold Zwicky's post at Language Log.)
Martin Willett, in the glossary of his Debate Unlimited website, notes that as a newt doesn't need a word meaning 'drunk' in order to convey drunkenness:
Pissed as a newt and pissed as a fart; expressions of extreme drunkeness. The ending “as a newt” can be added to other expressions to express the concept of drunkness e.g. “Did you see Caroline Aherne receive her award last night, she looked, er, relaxed... as a newt.”On the internet, one also finds cute as a newt (a few times). Since this is on the Urban Dictionary and MySpace, we might suppose it's a recently coined phrase. It doesn't mean 'drunkenly cute', but something more akin to AmE cute as a bug.
Both these BrE phrases can be compared to drunk as a skunk, which involves a North American animal, but nevertheless is said in Britain as well. Like cute as a newt, we can presume that it's caught on in large part because it rhymes--not because of any lack of sobreity in skunks or because of the inherent attractiveness of newts.
This one phrase has taken rather longer than expected, so I'll leave the rest of the American animals for tomorrow (or thereabouts). Stay tuned...