No mammals are monogamous.
Extra-pair copulation ( EPC ) is a promiscuous mating behaviour in monogamous species . Monogamy occurs when one male mates exclusively with one female , forming a long term bond and combining efforts to raise offspring together ; extra-pair copulation occurs when one of these individuals mates outside of this pairing . Mammal . Most mammals are polygynous , but some can be monogamous or polyandrous .