雌性菱背响尾蛇可在体内储存精子长达5年
那些正在实行计划生育的人们在寻找吉祥物的时候可以考虑一下东部菱背响尾蛇。这种蛇的雌性在想要繁殖后代之前可以将精子在体内储存至少5年。
一条响尾蛇(学名Crotalus adamanteus)于2005年在佛罗里达被捕获，并作为私人收藏保留了5年。在这5年中，这条母蛇没有与其他蛇接触过。但是在2010年末，她竟然产下了19条幼蛇！为了弄清楚怎么回事，美国北卡罗来纳州立大学的Warren Booth从母蛇和小蛇身上收集了些DNA样品。
Booth是研究“单性生殖的”，即研究雌性生物不接受精子即可生产后代的现象。但是，在这个案例中，小蛇携带了其母亲所没有的基因，因此这条母蛇必定是在被捕获前就进行过交配并将精子储存起来了。
既往的研究已经表明，爬行动物可以将精子储存好几年，但是这是第一次通过遗传学进行确定。Booth怀疑其他的爬行动物储存精子的时间会更长。“到底多长，没人知道”他说。
伦敦动物学研究中心的William Holt说，现在很清楚了，蛇类具有不同于传统的繁殖方法，包括单性生殖和长期的精子储存，不过它们是如何做到的还不为人所知。（生物探索译）
相关英文论文摘要：
Molecular genetic evidence for alternative reproductive strategies in North American pitvipers (Serpentes, Viperidae): long-term sperm storage and facultative parthenogenesis
The first documentation of facultative parthenogenesis (FP) in non-avian reptiles (snakes) occurred in 1997, following the application of molecular genetic methods for parentage analysis, and since has been described in only four additional snake species. Here, in two species of live-bearing (viviparous) North American pitviper snakes, using microsatellite DNA fingerprinting, we describe the first record of a virgin birth by FP in the copperhead (Agkistrodon contortrix), and the first genetically confirmed case of long-term sperm storage (LTSS) of exceptional duration (5 years) in the eastern diamond-backed rattlesnake (Crotalus adamanteus). The capacity of female squamate reptiles (snakes, lizards, and amphisbaenians) to store viable sperm for extended periods of time is a competing hypothesis to FP, and it is often inferred when interpreting certain births where adult females have been isolated from adult male mates for prolonged periods. On reviewing the literature of certain cases of LTSS in snakes, we provide compelling support for the prevalence of FP, casting doubt over the widespread acceptance of LTSS. Accordingly, with the discovery of FP in squamates and the results of the present study, we advocate that in order to differentiate between LTSS and FP, especially under natural conditions, rigorous molecular testing will be required.
