盲鳗类似鳝鱼，身体往外分泌粘液，在海底蜿蜒游动。它们爱吃腐尸，总也吃不够。当它们碰到死鱼之后，强有力的身体就会依偎在死鱼的腔体之内，呆在其中，美滋滋地翻腾起来。然而，它们到底在干什么呢？

 Probably eating their way out of the carcass, according to a new study—and not with any sort of politesse, either. When they can't pack enough flesh into their tentacle-lined mouths, hagfish absorb the carcass's nutrients right through their skin.
    

 根据一项新研究，盲鳗很可能正在尸体中大吃特吃起来，而且一点也不客气。盲鳗用排列着触须的嘴巴吃肉还嫌不够，它们直接通过皮肤来吸收死尸中的营养。

 The salt concentration of a hagfish's tissue is the same as that of the seawater it normally swims in, suggesting that dissolved substances can cross the skin. To determine whether the animals can soak up nutrients as well as salt, physiologist Chris Glover of the University of Canterbury in Christchurch, New Zealand, and colleagues took a piece of hagfish skin and stretched it out in a flask containing a seawater-like solution on one side and a solution resembling a hagfish's own bodily fluids on the other. In the seawater, they dissolved radioactive amino acids and sugars, along with food coloring to test how permeable the skin was. After a few hours, the skin started to become radioactive as it absorbed the amino acids, the researchers reveal online this week in the Proceedings of the Royal Society B. The skin didn't allow food coloring through, however, suggesting that it selects nutritious detritus.
    

 盲鳗组织中的盐浓度跟它们通常所在海域的海水是一样的，这说明溶解的物质可以穿过它们的皮肤。为了确定这种动物能否像吸收盐分那样吸收养分，新西兰基督城坎特伯雷大学的生理学家克里斯·格洛弗及同事取了一块盲鳗皮，将其伸展开来，放进一个瓶里，皮肤的一边盛着类似海水的溶液，另一边盛着类似盲鳗体液的溶液。在海水那边，研究人员将放射性氨基酸、糖和食物色素溶解进去，以测试盲鳗皮肤的渗透性如何。研究人员本周在《皇家学会学报B辑》在线版上报道：过了几个小时，随着对氨基酸的吸收，盲鳗皮开始具有放射性；然而，食物色素却无法透过盲鳗的皮肤，这表明盲鳗皮可以选择吸收有营养的成分。

 This is the first time such feeding habits have been observed in a non-invertebrate animal, suggesting that hagfish may be a transitional organism between modern fish and invertebrates such as aquatic worms, which can absorb food through their skin.
    

 这是首次在非无脊椎动物中观察到这样的进食习性，说明盲鳗可能是一种过渡生物体，介于现代鱼类和像水丝蚓属那样的无脊椎动物之间。水丝蚓属动物是可以通过皮肤来吸收养料的。

 Although they don't have true vertebrae, hagfish are considered "proto-vertebrates" and have many similarities to vertebrates. The researchers say that their physiology holds hints to the origin of some vertebrate traits. Their absorbent skin appears to act like the gut in more complex animals, for example, and may help scientists understand how this system evolved.
    

 尽管盲鳗没有真正的脊椎，但它们被认为是“原始脊椎动物”，跟脊椎动物有许多相同之处。研究人员称，盲鳗的生理机能提供了一些线索，可以说明脊椎动物一些特性的来历。例如，在更为复杂的动物中，具有吸收功能的皮肤好像具有肠道一样的作用，这种皮肤可以帮助科学家们搞明白这样的系统是如何进化的。

 "It's an interesting and novel result," says fish ecologist Jeffrey Drazen of the University of Hawaii, Manoa. When it's not busy consuming cadavers, the hagfish's larger role in the food web remains a mystery, he says, as it's difficult to study fish that live this deep in the ocean. The new finding is the latest in a list of hagfish feeding habits that would make Miss Manners weep. For instance, hagfish coat a corpse they're interested in with slime exuded from pores in their bodies, keeping other scavengers at bay. "Nobody else wants it after that," Drazen says.
    

 夏威夷大学莫纳分校的鱼类生物学家杰弗里·德雷森说：“这是一项有趣而新颖的研究成果。”当盲鳗没有忙于吃死尸的时候，它们在食物网中更大的作用是什么呢？德雷森说，这个问题仍然是个谜，因为要想研究在如此深的海域中生活的鱼类是很困难的。在盲鳗一系列的进食习性中，通过皮肤进食是最新的发现，这种习性会使那些“守规矩的”动物伤心不已。例如，盲鳗钻进一具自己感兴趣的死尸中，同时从自身的气孔中分泌出粘液，把其他的食腐动物拒之在外。“它们进驻死尸之后，其他食腐动物都没有胃口了，”德雷森说。