Darwin jokes — jokes told by Darwin himself — were often told at someone else's expense. All of the following comments are his, and they are in fact funny (though not really hilarious).
Darwin Joke (1): Darwin loved to hunt, and while a student at Cambridge spent much of his time in his rooms practicing with his gun. But instead of firing real bullets, he fired caps. He comments:
The explosion of the cap caused a sharp crack, and I was told that the tutor of the college remarked, "What an extraordinary thing it is, Mr. Darwin seems to spend hours in cracking a horse-whip in his room, for I often hear the crack when I pass under his windows."
Darwin Joke (2): Darwin recalled his father, Robert Waring Darwin (right), as "the largest man whom I ever saw." Of him, Darwin writes:
Many persons were much afraid of him. I remember my father telling us one day with a laugh, that several persons had asked him whether Miss Piggott (a grand old lady in Shropshire), had called on him, so that at last he enquired why they asked him; and was told that Miss Piggott, whom my father had somehow mortally offended, was telling everybody that she would call and tell 'that fat old doctor very plainly what she thought of him.' She had already called, but her courage had failed, and no one could have been more courteous and friendly.
From: Life and Letters of Charles Darwin.
Darwin Jokes (3): Darwin recalled an embarrassing incident that occurred at a meeting of the Plinian Society when he was a student at the University of Edinburgh:
One evening a poor young man got up, and after stammering for a prodigious length of time, blushing crimson, he at last slowly got out the words, "Mr. President, I have forgotten what I was going to say."
Darwin Jokes (4):Adam Sedgwick, a professor at Cambridge, took Darwin, then twenty-two, on a walking tour in Wales to initiate him in the methods of geology. Darwin, recalling the an incident from their journey together, mocks Sedgwick:
We left Conway early in the morning, and for the first two or three miles of our walk he [Sedgwick] was gloomy, and hardly spoke a word. He then suddenly burst forth: "I know that the d—d fellow never gave her the sixpence. I'll go back at once;" and turned round to return to Conway. I was amazed, for I never heard before, or since, anything like an oath from him. On inquiry I found that he was convinced that the waiter had not given to the chambermaid the sixpence which he had left for her. He had no reason whatever, excepting that he thought the waiter 'an ill-looking fellow.' On my hinting that he could hardly accuse a man of theft on such grounds, he consented to proceed, but for some time he grumbled and growled.
From: Clark, J. W. and T. M. Hughes eds. 1890. The walking tour in North Wales. In: The life and letters of the Reverend Adam Sedgwick. 1: 379-381.
Darwin Jokes (5): During his travels in South America, Darwin thought the places he had to stay suffered by comparison with the typical English inn. He gives the following account of Brazilian hospitality:
On first arriving, it was our custom to unsaddle the horses and give them their Indian corn; then, with a low bow, to ask the senhôr [innkeeper] to do us the favour to give us something to eat. "Any thing you choose, sir," was his usual answer. For the few first times, vainly I thanked Providence for having guided us to so good a man. The conversation proceeding, the case universally became deplorable. "Any fish can you do us the favour of giving?"—"Oh! no, sir."—"Any soup?"—"No, sir."—"Any bread ?"—"Oh! no, sir."—"Any dried meat?"—"Oh! no, sir." If we were lucky, by waiting a couple of hours, we obtained fowls, rice, and farinha. It not unfrequently happened, that we were obliged to kill, with stones, the poultry for our own supper. When thoroughly exhausted by fatigue and hunger, we timorously hinted that we should be glad of our meal, the pompous, and (though true) most unsatisfactory answer was, "It will be ready when it is ready." If we had dared to remonstrate any further, we should have been told to proceed on our journey, as being too impertinent.