巨齿鲨的幼崽比成年人类还要大
巨齿鲨的幼崽比成年人类还要大
Research came out last year that revealed the mighty megalodon was indeed the ocean giant we believed it to be. At around 16 meters (52 feet) long with fins as long as an adult human’s body, they dwarfed other fish in the sea when they were alive. Now, a new study published in the journal Historical Biology has claimed that these ocean giants’ progeny were also giants in their own way, making their first few tail swishes in the open ocean at a size already larger than most adult humans.
去年的一项研究揭示了巨大的巨齿鲨确实是我们所相信的海洋巨人。它们身长约16米(52英尺)，鱼鳍和成年人身体一样长，使它们在世时在海里的其他鱼类相形见绌。现在，发表在《历史生物学》杂志上的一项新研究声称，这些海洋巨人的后代也以自己的方式成为巨人，它们在公海上最初的几次尾巴摆动的大小已经超过了大多数成年人类。
Rachael Funnel
The study was investigating the growth pattern and life expectancy of megalodon, Otodus megalodon, to shed light on their reproductive biology. "As one of the largest carnivores that ever existed on Earth, deciphering such growth parameters of O. megalodon is critical to understand the role large carnivores play in the context of the evolution of marine ecosystems,” wrote paleobiologist at DePaul University in Chicago and lead author of the study Dr Kenshu Shimada in a statement.
这项研究正在调查巨齿鲨的生长模式和预期寿命，以阐明它们的生殖生物学。“作为地球上曾经存在过的最大的食肉动物之一，破解巨齿鲨的生长参数对于理解大型食肉动物在海洋生态系统进化过程中所扮演的角色至关重要。”芝加哥德保罗大学的古生物学家，该研究的第一作者Kenshu Shimada博士在一份声明中写道。
Using computed tomography (CT) scanning technology, Shimada and colleagues were able to look at 'growth bands' in megalodon vertebral specimens, housed in the Royal Belgian Institute of Natural Sciences in Brussels. These bands are similar to tree rings, with each ring representing another year in the fishes’ lifetime. The results revealed the vertebra of a shark estimated to be nine meters long had 46 bands, meaning it was 46 years old when it died.
使用计算机断层扫描技术，Shimada和同事能够观察巨齿鲨脊椎标本中的“生长带”，这些标本保存在布鲁塞尔的比利时皇家自然科学研究所。这些年轮类似于树木的年轮，每个年轮代表鱼类生命中的另一年。结果显示，这条鲨鱼的脊椎骨估计有9米长，有46条带子，这意味着它死的时候46岁。
The vertebra of the extinct megatooth shark have growth rings like a tree, making it easier to estimate their age at death. DePaul University/Kenshu Shimada
This information could be used to back-calculate the shark's body size at birth, which told the researchers that it was a wee bonny megalodon measuring around 2 meters (6.6 feet) when it came into the world. They posit that this suggests Megalodon gave live birth and that these fish were capable of snacking on their siblings while waiting to be born. The sinister practice is known as oophagy or intrauterine cannibalism, and is seen in all extant lamniform sharks, says that study. A famous tale among shark biologists describes the moment a scientist was dissecting a dead female tiger shark who was bitten by a cannibalistic embryo that had survived inside the oviduct. If the findings are correct, it could mean that megalodon babies were the largest ever baby sharks.
这些信息可以用来反向计算鲨鱼出生时的体型，这告诉研究人员，这是一条瘦小的巨齿鲨，刚来到这个世界时，身长约2米(6.6英尺)。他们推测，这表明巨齿鲨是活产的，而这些鱼能够在等待出生的时候吃掉它们的兄弟姐妹。该研究称，这种邪恶的行为被称为食卵癖或子宫内同类相食，在所有现存的羊膜状鲨鱼中都可以看到。鲨鱼生物学家们流传着一个著名的故事:一位科学家解剖了一只雌性虎鲨的尸体，这只虎鲨被一个存活在输卵管内的同类相食的胚胎咬伤。如果这些发现是正确的，这可能意味着巨齿鲨宝宝是有史以来最大的小鲨鱼。
Megalodon is a popular species among shark fans, regularly featuring in sci-fi movies such as The Meg. While the fossil record of these apex predators is rich, we still don’t know very much about their biology. This is a common problem in cartilaginous fish, who rarely leave much to be found in the fossil record other than teeth. This is why the discovery of their gigantic vertebrae represents such an exciting opportunity academically speaking, as scientists work to close the gap in our knowledge of these fearsome hunters.
巨齿鲨在鲨鱼迷中很受欢迎，经常出现在《巨齿鲨》等科幻电影中。虽然这些顶端食肉动物的化石记录很丰富，但我们仍然不太了解它们的生物学。这在软骨鱼类中是一个常见的问题，除了牙齿以外，在化石记录中，软骨鱼类很少留下其他东西。这就是为什么发现它们巨大的脊椎骨在学术上代表着如此令人兴奋的机会，因为科学家们正在努力缩小我们对这些可怕的猎人的了解。
