大白鲨通常被认为是很大程度上独居的动物，它们只是聚在一起交配。然而，研究首次揭示，掠食者可能有目的地形成“群体”，并持续地与某些群体呆在一起。
科学家们已经知道，根据季节不同，大量的大白鲨会定期聚集在特定的地点，在它们的聚居地捕食小海豹。它们有时也会成对或成群出现在大型尸体周围。
此前，研究人员解释说，这些聚会在本质上是随机的，鲨鱼只是为了食物而来，而不是因为它们想与同类中的其他个体互动。
然而，根据发表在杂志上的一项研究，大白鲨可能比以前想象的更加社会化行为生态学和社会生物学。
在这项研究中，澳大利亚新南威尔士麦格理大学的斯蒂芬·洛伊领导的一个科学家小组研究了经常大量聚集在海王星群岛(位于澳大利亚南部海岸)的白鲨。该地区靠近一个海豹保育室，号称是全国最大的大白鲨聚集地。
在四年半的时间里，从2010年6月到2014年11月，研究人员监控了近300条鲨鱼，这些鲨鱼通过拍照来访问该网站，以便识别个体。他们还进行了网络分析，以确定鲨鱼是否聚集在特定的群体中。
他们的观察显示，许多鲨鱼被发现在其他鲨鱼旁边的频率比偶然发现的要高。这让研究人员第一次得出结论，许多鲨鱼喜欢在某些群体中出没，这种关系可以持续几年。
洛伊在一份声明中说:“鲨鱼不是随机出现，而是形成了四个不同的群落，这表明一些鲨鱼比预期的更有可能偶然同时使用这个网站。”。
“这些数字随时间而变化，我们认为海王星群岛基于性别的探访模式驱动了观察到的社区结构，”他说。
尽管他们有最新的发现，该小组仍然不确定鲨鱼形成这些持久群落的原因。
“我们的发现表明白鲨不是偶然聚集的，但是需要更多的研究来找出原因。”
库存照片:一只大白鲨。
这不是最近出现的白鲨相互作用的第一个证据。今年早些时候，研究人员捕捉到了两条大白鲨相互作用在马萨诸塞州科德角的一个不同寻常的展示中。
马萨诸塞州海洋渔业部门的格雷格·斯科尔此前告诉记者新闻周刊这段视频是他的组织中第一次有人看到白鲨之间的社交互动。此后，研究人员一直在分析这段视频，看它是否表现出攻击性/防御性行为，或者它是否在某种程度上与交配有关。
非营利组织OCEARCH的研究人员用标签追踪大白鲨，他们认为在西北大西洋有两个白鲨亚种群:一个在夏末秋初聚集在鳕鱼角地区，另一个在加拿大聚集。
“所以在对西北大西洋白鲨的研究中，我们一直在追踪这些大动物，从加拿大大西洋一直到佛罗里达半岛，”OCEARCH的首席科学顾问罗伯特·亨特在该组织脸书页面上的一段视频中说。
“我们注意到一件有趣的事情，那就是有些动物在夏天会去科德角地区觅食。还有其他一些绕过科德角，来到新斯科舍省觅食，”他说。“所以现在我们正在研究西北大西洋有无可能出现两种截然不同的白鲨群体或亚群体。”
太平洋上甚至有一个地方被称为“白鲨咖啡馆”——一片160英里宽的看似贫瘠的海洋，通常生活在北美西海岸的白鲨每年冬天都会去那里。这种不寻常的迁移困惑了几十年的科学家。
GREAT WHITE SHARKS LIKE TO HANG OUT WITH EACH OTHER WHEN FEASTING ON BABY SEALS, SCIENTISTS FIND
Great white sharks are normally thought of as being largely solitary animals that only come together to mate. However, research has revealed for the first time that the predators may purposefully form "communities" and consistently spend time with certain groups.
Scientists already knew that large numbers of great whites periodically aggregate in certain locations, depending on the season, to hunt baby seals in their colonies. They have also sometimes been spotted in pairs or small groups around large carcasses.
Previously, researchers explained the gatherings by saying they are random in nature, that the sharks only came for the food and not because they wanted to interact with other individuals from their species.
However, great whites may be more social than once thought, according to a study published in the journal Behavioral Ecology and Sociobiology.
For the study, a team of scientists led by Stephan Leu from Macquarie University in New South Wales, Australia, examined white sharks that frequently gather in large numbers at a site in the Neptune Islands—located off Australia's southern coast. This area, near a seal nursery, lays claim to hosting the largest aggregation of great whites in the country.
Over the course of four-and-a-half years, between June 2010 and November 2014, the researchers monitored nearly 300 sharks that visited the site using by taking pictures so that they could identify individuals. They also conducted a network analysis to determine whether or not sharks were gathering in specific groups.
Their observations revealed that many of the sharks were spotted next to others more frequently than would be expected by chance. This led the researchers to conclude, for the first time, that many of the sharks like to hang out in certain groups, and that these relationships can last for several years.
"Rather than just being around randomly, the sharks formed four distinct communities, which showed that some sharks were more likely to use the site simultaneously than expected by chance," Leu said in a statement.
"The numbers varied across time, and we suggest that sex-dependent patterns of visitation at the Neptune Islands drive the observed community structure," he said.
Despite their latest findings, the team is still unsure of the reason behind the sharks forming these persistent communities.
"Our findings show that white sharks don't gather just by chance, but more research is needed to find out why."
Stock photo: A great white shark.
This is not the first evidence that has emerged recently of white sharks interacting. Earlier this year, researchers captured fascinating footage of two great white sharks interacting with each other in an unusual display in the waters off Cape Cod, Massachusetts.
Greg Skomal from the Massachusetts Division of Marine Fisheries (DMF) previously told Newsweek that this video was the first time anyone from his organization had seen social interaction between white sharks. Researchers have since been analyzing the video to see whether it demonstrates aggressive/defensive behavior, or if it is related to mating in some way.
Researchers from non-profit OCEARCH—which tracks great whites with tags—have suggested that there are two sub-populations of white sharks in the Northwest Atlantic: one that aggregates in the Cape Cod area in the late summer and early fall and another that aggregates in Canada.
"So in the study of the white shark in the northwest Atlantic, we're tracking these big animals all the way from Atlantic Canada to all the way down in the Florida peninsula," Robert Hunter, OCEARCH's chief science adviser, said in a video on the organization's Facebook page.
"Something fascinating that we've noticed is that there are some animals that go to the Cape Cod area in the summertime to feed. And then there are others, that have bypassed cape cod and come up Nova Scotia to feed," he said. "So right now we are looking at the possibility of two distinct groups or subpopulations of white sharks in the northwest Atlantic."
There is even a place in the Pacific Ocean known as the "White Shark Café"— a 160-mile wide stretch of seemingly barren ocean where white sharks that normally live off the North American West Coast travel to every year during the winter. This unusual migration has puzzled scientists for decades.
