“一夫一妻制”在動物王國中并不多見，這里介紹10種對情感忠貞不二的動物，它們是動物界中的癡心者。

　　Prarie Vole

　　Although monogamy in the animal kingdom is rare, it's far from boring. Consider males of this mouse-like species, for example. They will stick with the female they lost their virginity to. Far from eyeing other females, a mated male vole will actually attack other females. Scientists have traced this behavior to hormones in the rodent’s brain, which triggers lasting bond formation and increased aggression toward potential home wreckers.

　　普拉里田鼠

　　這種田鼠名叫普拉里（Prarie Vole）。雄普拉里鼠一輩子只和將處女之身獻給它的雌普拉里鼠生活。雄普拉里鼠不但不會多看其它雌鼠一眼，甚至還會攻擊其它雌鼠。目前，科學家已經將普拉里鼠的癡情行為和它們腦中分泌的荷爾蒙聯系起來。科學家認為，這種荷爾蒙不但讓普拉里鼠夫婦間保持著長期穩定的伴侶關系，還讓他們天生就對可能破壞家庭的第3者具有進攻性

Argiope aurantia spiders

　　Males from many spider species die during or after *, but that's because the females eat them. Male A. aurantia spiders willingly sacrifice themselves while mating: During *, a male will leave one of its mating appendages inside the female's body, where it acts as a kind of organic chastity belt, preventing her from mating with other males.

　　阿吉普奧蘭提亞蜘蛛

　　許多雄蜘蛛都與雌蜘蛛交配時或交配后死去，因為雌蜘蛛會吞食配偶。而雄性的阿吉普奧蘭提亞（Argiope aurantia）蜘蛛卻在交配時自愿犧牲自己的生殖器。交配時，雄性的阿吉普奧蘭提亞蜘蛛會將生殖器的一部分留在雌蜘蛛體內，這使得雌蜘蛛就像是中世紀被系上了貞操帶的婦女，再也無法與其它雄蜘蛛交配

Bonnethead shark

　　Females of this small hammerhead shark species were thought to mate with several males and store their sperm for later use, so scientists assumed the resulting litter of baby sharks would have several different fathers. It was thus a surprise when studies revealed most litters are sired by the sperm of just one father. The finding suggests the females are either *ually monogamous, mating with only a single male, or that they mate with many males but that the sperm of one out-competes the others.

　　窄頭雙髻鯊

　　科學家曾認為，雌性窄頭雙髻鯊有不同的性伴侶并將不同的雄鯊精子儲存在體內供今后孕育幼鯊，于是雌性窄頭雙髻鯊產下的每胎小鯊魚都可能有若干個父親。然而，當研究人員對不同胎的小鯊魚做親子鑒定時卻有了驚人的發現——大部分幼鯊都是同一個父親的孩子。研究結果表明，雌性窄頭雙髻鯊可能只與同一條雄鯊進行交配，也可能與多條雄鯊交配但只儲存來自一條雄鯊的精子

Red-backed Salamander

　　Male red-backed salamanders will physically and *ually harass their female mates if they suspect infidelity, or even mere associations between the female and other males. But philandering females are used to this, and studies show they are more adept at escaping their aggressive partners compared with socially monogamous females.

　　紅背蜥蜴

　　雄性的紅背蜥蜴愛“吃醋”，它們一旦懷疑配偶不忠或僅僅是與其它異性來往過密，就會攻擊配偶身體或是進行性虐待。但研究顯示，“水性楊花”的雌性紅背蜥蜴也習慣了丈夫的這種“小心眼”，與其它受一夫一妻制約束的雌性動物相比，雌性紅背蜥蜴能更熟練地逃脫丈夫的懲罰

Kirk's dik-dik antelope

　　Unlike most *ually monogamous mammals, males of this African dwarf antelope species mate with the female but don't share in the parenting responsibilities.

　　喀氏小羚羊

　　和大部分單配偶哺乳動物不同的是，這種非洲小羚羊中的雄性雖然只有一個“老婆”但不會幫“老婆”養育幼崽