monotocous

adj.[动]一次产一卵的,(产)单胎的,一胎产一仔的

having only one sexual partner during a breeding season（在繁殖季节中只有一个性伴侣）

形容词

Male antechinuses are monotocous, mating only once during their short lifespan.

蚁鼠雄性是一夫一妻制的，它们在短暂的寿命中只会交配一次。