Separated by a common language

Once again, I am surpised at the differences between the American and English languages. So close, and yet... Case in point: What would you call this:
If you're American, I'm thinking you'll guess crib. Nope. Over here it's a cot. Or technically a cot-bed, which I think is marginally larger than a cot, and can convert into a bed. Isn't a cot a bed, you ask? Y'know, those narrow things you sleep on at camp? Er, I guess not.

For some reason, a crib is only the smaller version you put a newborn in. Not to be confused with the reaaally small one, which would be called a Moses basket, which some newborns get instead. Eek.

What I really don't understand is how in a few hundred years our language has diverged in such random spots. Presumably little babies of English emigrants to America slept in something -- and it was called the same thing on both sides of the pond. And yet at some stage, when production and naming of said items were being standardised (the industrial era?), the English decided on crib to cot, and Americans said hey, crib's enough for us. Unless it's a small rocking one, in which case we'll use cradle. Which, as far as I can tell, isn't in regular use in the UK.

Augh!! See -- I will be raising a bilingual child!