Detail of two monkeys playing trumpets in an unusual manner, from the Maastricht Hours, Liège, 1st quarter of the 14th century, Stowe MS 17, f. 61v - See more at: http://britishlibrary.typepad.co.uk/digitisedmanuscripts/2015/07/happy-uncommon-musical-instrument-appreciation-day.html#sthash.FnKoayeE.dpuf
Difficult to ignore, however, is the episode just beneath the central scene: one ape holds the same book, another uses his hindquarters as a lectern, and the antics of both are overseen by a laughing skeleton! -
Detail of a mother ape being hunted, from the Queen Mary Psalter, England, c. 1310 – c. 1320, Royal MS 2 B VII, f. 107v The Bestiary developed these themes (see the copy in Royal MS 12 F XIII here) by giving an account of a mother ape fleeing hunters and carrying twins, her favourite in her arms and her least favourite on her back.
And then there is this very helpful ape, picking (and eating) fleas from a human head – a very unusual motif and one good indication that you are looking at work by ‘the Caesar Master’. The contemporary ‘catch all’ term for animal antics in the margins of medieval manuscripts is thought to have been babuini (Latin) or babewyn (Middle English), meaning ‘baboon-like’ or ‘monkey-business’.