Why howler monkeys, you may well ask? I have no excuse except that when I came across the superlative it seemed quite intriguing. Doubtless some monkeys have achieved a greater number of penile thrusts, but if they have I do not know of them. In one set of observations a male howler monkey managed no less than twenty-eight penile thrusts in a single intromission, after which period we may deduce that climax occurred or the fellow got bored.