在古希腊神话中，九头蛇让战神赫拉克勒斯总有种如鲠在喉的感觉，而在海洋世界里，双头海蛇也让食肉动物有了同样的感觉。
瑞典克里斯蒂安斯塔德大学的生态学家约翰·埃尔姆博格(Johan Elmberg)和丹麦哥本哈根动物保护学院的生物学家阿恩·拉斯穆森(Arne Rasmussen)在刊登于《海洋生态学》(Marine Ecology)的最新研究报告中写道，像厚尾海蛇(Hydrophis pachycercos)这样的海蛇种类不断进化，使得鲨鱼等海洋食肉动物无法分辨这种大蛇是来还是去。
埃尔姆博格说，一次，拉斯穆森去印度尼西亚进行科考研究，“他看到一只分泌毒液的海蛇先是一头钻进狭窄的裂缝，接着，他吃惊地发现，这条海蛇后面竟然还长着个头，看上去它可以在裂缝中非常快速灵活地转身。”过了一会儿，拉斯穆森才意识到，后面的“头”其实是尾巴。
埃尔姆博格介绍说，这是一种黄唇毒蛇，昼伏夜出，在浅水活动，“还在暗礁裂缝中穿梭寻找鱼类”，“尾巴慢慢地来回扭动，而头部也几乎以相同方式移动。”后来，经过对保存在欧洲三个不同博物馆的98个3英尺长(约合1米)热带蛇种标本的细致研究，两位研究人员得出了这样的结论：所有黄唇海蛇都有两个头。
埃尔姆博格说：“我认为这种双头模式和来回摇摆移动可能会吓走潜在的食肉动物，让它们误以为尾巴是有毒的头。”此后，埃尔姆博格和拉斯穆森又在所罗门群岛所在的南太平洋水域和别的地方发现，像厚尾海蛇这样的海蛇种类都具有相似的特征。尽管埃尔姆博格和拉斯穆森并未亲眼见到厚尾海蛇像头一样扭动它们的尾巴，但二人都认为它们肯定会这样做。（生物谷Bioon.com）
生物谷推荐原始出处：
Marine Ecology Date: July 2009
'Head for my tail': a new hypothesis to explain how venomous sea snakes avoid becoming prey
Arne Redsted Rasmussen 1 & Johan Elmberg 2
1 The Royal Danish Academy of Fine Arts, School of Conservation, Copenhagen, Denmark
2 Aquatic biology and chemistry, Kristianstad University, Kristianstad, Sweden
Sea snakes are widespread and conspicuous inhabitants of shallow waters in the Indian and Pacific Oceans. They are agile top predators and possess extremely potent venom, but they are still susceptible to predation by large fish, e.g. sharks, and other vertebrates. We describe how crevice-probing and temporarily non-vigilant Yellow-lipped Sea Kraits Laticauda colubrina twist the tail around their length axis so that the tail tip's lateral aspect corresponds to the dorsal view of the head. In doing so, coloration and pattern in combination with tail movement and posture make the tail appear very similar to the (non-visible and foraging) head. We examined 98 Laticauda spp. sea snakes in three major museum collections and reviewed the literature to assess the generality and implications of our field observations. This leads us to hypothesize that a combination of: (i) head and tail being similarly coloured and patterned, and (ii) the tail being motioned to resemble the head, is a hitherto overlooked mimetic and 'prophylactic' anti-predator adaptation in the L. colubrina complex, and possibly in other species of sea snake. We propose this is a concerted behavioural–morphological adaptation, and we briefly speculate about its possible fitness trade-offs as well as its origin. Explicit and testable predictions derived from the hypothesis are presented.
