Fans of the movie Master and Commander will probably point to Jack Aubrey's 'lesser of two weevils' joke as a jolly example of humour within Patrick O'Brian's writing. Readers of his Aubrey-Maturin books know that life aboard the Surprise is laced with humour.
Perhaps it's Stephen's debauched sloth in HMS Surprise which provides one of the more loveable examples of humour in the series. Like most sailors, the Surprises are prone to superstition, and like most Englishmen they are fond of pets. They also follow military norms by taking the animal to their hearts as a lucky mascot, and Jack even shares his grog with it to console the seasick creature during a storm.
The sloth sneezed, and looking up, Jack caught its gaze fixed upon him; its inverted face had an expression of anxiety and concern. 'Try a piece of this, old cock,' he said, dipping his cake in the grog and proffering the sop. 'It might put a little heart into you.' The sloth sighed, closed its eyes, but gently absorbed the piece, and sighed again.
Some minutes later he felt a touch on his knee; the sloth had silently climbed down and it was standing there, its beady eyes looking up into his face, bright with expectation. More cake, more grog; growing confidence and esteem. After this, as soon as the drum had beat the retreat, the sloth would meet him, hurrying towards the door on its uneven legs: it was given its own bowl and would grip it with its claws, lowering its round face into it and pursing its lips to drink. Sometimes it went to sleep in this position, bowed over the emptiness.
"In this bucket," said Stephen, walking into the cabin, "in this small half-bucket, now, I have the population of Dublin, London and Paris combined: these animalculae - what is the matter with the sloth?" It was curled on Jack's knee, breathing heavily: its bowl and Jack's glass stood empty on the table. Stephen picked it up, peered into its affable, bleary face, shoot it, and hung it upon its rope. It seized hold with one fore and one hind foot, letting the others dangle limp, and went to sleep.
Stephen looked sharply round, saw the decanter, smelt to the sloth, and cried, "Jack, you have debauched my sloth."
It's got to be one of the best comic set pieces of the series. However, it is not the only time O'Brian makes use of drunken animals in the series. There's also Babbington's ape in Post Captain.
'A damned ill-conditioned sort of an ape. It had a can of ale at every pot-house on the road, and is reeling drunk. It has been offering itself to Babbington.'
From what I remember of the swarming bumboats in harbour and Babbington's generally low standards with women, he probably accepted the ape's hospitality.