The "paragraph" in our genes describing the protein called cytochrome c is 339 letters long [...] 45 letter changes separate humans from yeast and the same number separates pigs from yeast.
[Richard Dawkins, 1995, River out of Eden, p. 42]
Quando due arvicole di prateria di sesso opposto si incontrano e si piacciono si lanciano in un tour de force sessuale che comprende più di una quindicina di accoppiamenti nel giro di un solo giorno. Al termine di questa maratona dell'amore i due topolini sono irrimediabilmente legati da un legame stabile e sono estremamente fedeli. Il maschio arriva a scacciare femmine in estro qualora queste si avvicinino al nido (un comportamento veramente inusuale per un roditore).
[Alessandro Cellerino, 2002, Eros e cervello, p. 179]
Jill, a forty-two-year-old premenopausal schoolteacher, had come to me complaining of no libido—which was causing marital problems. Her blood level of testosterone was very low, so I began treating her with testosterone therapy [...]I asked her to come back in three weeks to assess her progress. During the time between appointments, Jill mistakenly doubled her dose of testosterone. Her face was blushing bright red when she came into the clinic. She sheepishly told me of her mistake and said her sexual urges were now so strong that she was running into the bathroom between classes to masturbate. She said, “This is becoming a real bother, but now I know what it must feel like to be a nineteen-year-old boy!”
[Louann Brizendine, 2006, The Female Brain, p. 90]