爱华网其名为“座头”，源名为「座頭」（ザトウ），意为“琵琶”，是指鲸鱼背部的形状。这是一种大型的鲸鱼，多大呢？一只成年的座头体长可达12到16米，体重近30多吨，平均寿命可以达到40年，胸鰭最长可达5米，也就是接近三个成年人的身高。
上图中(1)位置的就是座头鲸，(2)~(5)中dolphin海豚和porpoise鼠海豚是齿鲸（多谢 提醒），而第(6)位置上的就是大家比较熟悉的长须鲸。
座头鲸头部及下颚部分遍布类似乳突状的小型节瘤突起，不过这些小瘤其实是它们的毛囊。图片来自图片来自
这种长着痘痘的鲸鱼虽然其貌不扬，但是因为在海中与其死敌“虎鲸”的英勇斗争（包括营救群体中弱小幼崽、破坏虎鲸的狩猎行动、避免已死猎物被虎鲸分食），常常被冠以“海中义警”（sea vigilante）的称号。这种“我很丑但我很温柔”的匡扶正义，绝对可以称的上自然界中“友好”的现象。
在今年7月这篇发表在《Marine Mammal Science》的文章"Humpback whales interfering when mammal-eating killer whales attack other species: Mobbing behavior and interspecific altruism?”中，作者们讲述了个中的可能原因。
图片来自图片来自
可以看到上图为不同海域发生过的“正义”行为，数字代表发生事件的数量。在从1951年到至2012年为止，Pitman和他的合作者们收录了来自54个不同目击者报道的115次座头鲸特性事件——这些事件中包括育带幼崽或者独自作业的来自不同海域的不同座头鲸与虎鲸的互动行为（interactions）。
尽管在这些事件中，虎鲸几乎是剧中的“坏人”——海洋哺乳动物的捕食者（占到事件中的95%），然而座头鲸在多数情况下却是进攻的发起者，或者说是挑衅的一方（53% vs 47%）。当虎鲸接近座头鲸时（27次），它们一般会锁定幼崽攻击（85%）。当座头鲸接近虎鲸时（41次），虎鲸大部分都在狩猎或者进食（87%）。当座头鲸发动对虎鲸的干扰行为时，只有11%情形下是拯救自己或者族群的幼崽，多达89%的情形是保护其他10类物种，这其中包括了另外三只鲸目物种的远亲（three cetaceans）、6只鳍足亚目动物（six pinnipeds）和一只硬骨鱼类（one teleost fish）。在56次的交互行为中，超过55%的情况都是座头鲸发动对虎鲸的群攻为猎物们解围，让它们伺机逃跑。起初，作者们以为这只不过是座头鲸对于虎鲸捕猎作声的一种积极响应，甚至可以说是一种报复行为。但除了可以用亲缘选择或者种内互惠主义解释座头鲸对于同种幼崽的相互庇护之外，并没有明显的惠利解释可以用来解释他们这种持续守护虎鲸猎物的行为。那么，尽管有可能并不是有意为之，但物种间的利他主义行为也许是一个不容忽视的解释。
事件种类A：种内营救
Photo: © Flip Nicklin/Minden PicturesPhoto: © Flip Nicklin/Minden Pictures
这张图件拍摄的有些“延迟”，事件是用拍摄者的话语还原的：2003年，在阿拉斯加的阿留申群岛附近，17条过境型虎鲸（Bigg‘s Killer Whale，虎鲸的一种）围捕一只体型较大的幼崽、母座头鲸和另外一头护卫座头鲸，在上图的背景里面你可以看到落荒而逃的几只虎鲸的背鳍（仔细看），危机之中，有另外三头成年座头鲸加入并协助驱散了虎鲸群。
此外，在必要的情况下，母座头会使用巨型胸鳍片来保护幼崽座头，如下图所示：
Photo: © M. Lynn, NOAA, Southwest Fisheries Science Center
事件种类B：种间营救
（Examples of humpback whales interacting with mammal-eating killer whales attacking various prey species: (A) large type B killer whales attacking a crabeater seal hauled out on an ice floe with an agitated (bellowing) humpback in the foreground; January 2009, Western Antarctic Peninsula, Appendix S2 account #89; photo by J. Durban; (B) Bigg's killer whales attacking a gray whale calf (gray whale mother on left; wounded calf in center) with a humpback whale in the background; May 2012, Monterey Bay, CA, #55; photo E. Robinson courtesy Monterey Bay Whale Watch; (C) Bigg's killer whales attacking a Steller sea lion with humpback in the immediate background; 21 August 2010, Vancouver Island, Canada, #67; photo by R. Frank; (D) Bigg's killer whales attacking a harbor seal (below trailing edge of killer whale dorsal fin; the seal has a transmitter mounted on its head) and a humpback in the background; June 2005, Glacier Bay, AK, #91; photo by M. de Roos.）
图A：大型B类虎鲸正在准备袭击一只驻足于冰块上的食蟹海豹，不远处的一只座头鲸表示出了担忧；图B：几只过境型虎鲸围猎一只灰鲸幼崽。受伤的幼崽在图的中央，母灰鲸在图的左侧。一只应声前来的座头鲸破坏了围猎的进程；
图C：还是几只过境型虎鲸狩猎一头北海狮，一只勇猛的座头鲸迅速解围；
图D：依旧是几只过境型虎鲸袭击猎物，这次换成了一头麻斑海豹，一只座头鲸从背景里嗖地杀出解围；
······虎鲸表示很无奈······
对于图A，《Science》官网上有一篇详细的报道：
At first it seemed like the usual, deviously clever attack. Several killer whales were trying to catch a Weddell seal that had taken refuge atop a drifting patch of Antarctic ice. The orcas swam alongside each other, creating a wave that knocked the hapless pinniped into the water. Death seemed certain.
Then something amazing happened: A pair of humpback whales turned up. As the panicked seal swam toward them, a lucky wave tossed it onto the chest of the closer, upturned whale. The whale arched its chest out of the water, which kept the seal away from the charging killer whales. And when the seal started to fall off, the whale carefully pushed it back onto its chest with a flipper. Soon after that, the seal scrambled to safety on another ice floe.
在图A的情形下，一眼望去，便可见虎鲸的聪明计划：巡游击之。几只虎鲸将一只威德尔氏海豹死死困在一块看似救命稻草般的南极冰川上。虎鲸们进行了依次游动，制造出一波一波的浪花企图把这只倒霉的鳍足小哥拍到水中。海豹已然绝望。
但说时迟那时快，一对座头鲸斜刺里杀出。正当慌了神的海豹急速游向它们的时候，一朵及时的浪花幸运地将海豹抛到了就近一只座头鲸的胸膛之上，也是巧了，这只座头正好翻身向上。只见这只座头将胸部拱出水面，挡住了气势汹汹的虎鲸游冲。同时，当海豹将要从弱侧滑落之时，座头又适时地用鳍片将豹爷扇了回去（画面太美）。紧接着，海豹迅速地匍匐至安全之地——另一块冰川。
大家可以看一下最关键的画面：
Photo：© Robert Pitman/NOAAPhoto：© Robert Pitman/NOAA
这只豹爷几乎是乘着座头的胸部破浪而逃，完成了对虎鲸围捕的金蝉脱壳。
对于图B，这个时间被BBC Planet Earth Alive节目组记录的淋漓尽致：
至少有不下五只的过境型虎鲸参与围猎：
灰鲸母子被顺利分割，一只虎鲸势不可挡，灰鲸幼崽则疼痛难忍：灰鲸母子被顺利分割，一只虎鲸势不可挡，灰鲸幼崽则疼痛难忍：两只座头鲸及时解围，那长满痘痘的大嘴不是座头还能是谁？两只座头鲸及时解围，那长满痘痘的大嘴不是座头还能是谁？座头鲸（喷水）成功地隔开虎鲸群（背景）与灰鲸幼崽后，深藏功与名。座头鲸（喷水）成功地隔开虎鲸群（背景）与灰鲸幼崽后，深藏功与名。尽管灰鲸幼崽已经在围杀中身亡，但据节目组说，座头鲸们还是守护在尸体旁避免其被虎鲸群分食殆尽。尽管灰鲸幼崽已经在围杀中身亡，但据节目组说，座头鲸们还是守护在尸体旁避免其被虎鲸群分食殆尽。在上述不同种类的事件中，座头鲸的反应能力似乎是惊人的，有个别的案例甚至提及几公里远之外的座头鲸闻声而动，这或许与鲸类本身的声波交流有一定的关系。我们看下面：
Do Humpbacks Respond to Killer Whale Attack Vocalizations?
Another question concerns how humpbacks were able to detect attacking MEKWs that were sometimes over 1 km away. We propose that they were responding to acoustic cues—cues from the MEKWs and not their prey.
Unlike fish-eating killer whales,MEKWs in the North Pacific, and probably globally, are mostly silent when they hunt, presumably because their mammalian prey species all have acute hearing capabilities (Barrett-Lennard et al. ; Deecke et al. , ; Riesch and Deecke ). For example, it has been shown that when gray whales, harbor seals, belugas (Delphinapterus leucas), and sperm whales are exposed to playback calls of MEKWs, they respond with various antipredator behaviors (Cummings and Thompson , Fish and Vania , Deecke et al. , Curé et al. ). Humpbacks in the eastern Atlantic also appear to avoid MEKW vocalizations (Curé et al. ).
Once MEKWs have detected potential prey, however, they often become vocally active, during and after attacks (Morton , Guinet , Goley and Straley , Barrett-Lennard et al. , Deecke et al. , Ford et al. , Deecke et al. , Riesch and Deecke ). As Reeves et al. () suggested, “active sound processing presumably becomes allowable, and perhaps functionally important, once contact with the prey has been established.” The reason(s) for vocalizing in this context is not currently understood, but it could be important for coordinating attack behavior, or for calling in other killer whales—either to assist in the attack, to share in the kill, or for socializing (Deecke et al. ).
We suggest, therefore, that when humpback whales approached attacking MEKWs, they were responding to the attackers’ vocalizations. Four observations support this notion: (1) MEKWs and fish-eating killer whales occur sympatrically in the NE Pacific, and presumably elsewhere. They have type-specific vocalizations (Ford and Fisher , Riesch and Deecke ), which humpbacks should be able to distinguish (Deecke et al. ); (2) humpbacks approached MEKWs (vs. fish-eaters) in the large majority of cases (93%; n = 41), and when they did, at least 84% (n = 32) of the MEKW groups were already attacking or feeding on various prey species; (3) although infrequently reported in Appendix S2, the distances that some of the humpbacks traveled when they approached killer whales were obviously well beyond the visual range of humpbacks. For example, on four occasions humpbacks reportedly traveled 1.6 and 7.6 km before approaching MEKWs that were attacking a humpback whale, a gray whale, a Steller sea lion, and a California sea lion (#4, 55, 59, 77, respectively); and (4) on two occasions, observers with hydrophones specifically recorded MEKWs vocalizing at an attack site before the humpbacks arrived (#90, 97).摘自
虎鲸们在捕猎的时候通常是安静行动，这或许是因为它们的猎物本身也对声线比较敏感。但是在进行猎杀或者攻击行动之时，虎鲸则会表现得声腔全开，这个原因目前还不得而知，但是可以推测其目的也许是为了更好地协作围猎或者是呼叫同伴加入。作者认为，座头鲸对于虎鲸的发声有特别的甄辨能力，这在大量的事件面前是站得住脚的推论（93%）。因为在部分例子中，座头鲸从远处巡航追击虎鲸的距离常常超过它们的视力范畴极限，这明显是根据声线反应的佐证。最为惊人的是，其中某个例子下，座头鲸竟然潜行7.6公里去干扰虎鲸的狩猎。
对于座头鲸的“见义勇为”，海洋生物学家们有着自己的看法：
It’s not hard to imagine why humpbacks would rush to the rescue when another humpback whale is under attack. Because they migrate to and from the same breeding grounds where they were born, humpbacks are likely to encounter relatives. So a threatened calf might share some genes with a rescuer, making the apparently altruistic act of saving it somewhat self-interested.
But what about protecting other species? This happened in nearly 90% of attacks where the killer whales’ prey could be identified. “It’s pretty mysterious,” says Trevor Branch, a fisheries scientist at the University of Washington, Seattle, who has studied populations of large whales. “We tend to think of altruism as being reciprocal, but there’s no way these other species would come back and help the humpback whales.”
Pitman suspects that it is inadvertent altruism. The humpbacks might simply rush to the scene of a fight whenever they hear killer whales fighting. “I think they just have a simple rule,” Pitman says. “When you hear a killer whale attack, go break it up.” Clapham adds that the confrontations may teach the killer whales a lesson, making them think twice about messing with humpbacks.
摘自
对于救助自己的同伴或者群族的幼崽，跟座头鲸的生活习性有关。在相同海域的孕育之下，整个族群的座头鲸对于“家乡”有着很强的归属感，因而对同伴的熟悉程度也相当之大。在往返繁殖地之间，它们很容易就碰到自己的“亲戚”。所以一只濒临危险的幼崽也许跟营救者萁豆同根、烟焰同源，那么出手搭救也就合情合理。
但超过90%的情形则来自不同物种，如果说解救系内同伴情有可原，那么帮助种外生物则毫无利益可言，因为救助者通常无法给与相应的回报。
皮特曼认为，座头鲸的见义勇为属于无意间的利他行为。也许是因为座头鲸对于跟虎鲸刚正面的兴趣吸引他们到达了战斗地点，又或者它们只是想单纯的破坏虎鲸的狩猎行动。
但不管如何，这种锄强扶弱的“热血”行为确实是自然界弱肉强食中难得一见的友爱现象。
庄子在《知北游》中说过：
天地有大美而不言，四时有明法而不议，万物有成理而不说。
这或许就是我们期望的自然之美。
以上参考：
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[2]
[3]
[4]
[5]
[6]
[7]
[8]
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9月23号更新
有评论问到柔弱的须鲸如何与凶猛的虎鲸刚正面。
well，则个问题问的好，问得好啊
秘技——藤壶杀！
大家吃斧足类软体动物（贻贝、生蚝等等）的时候可能会有见过这种附着在表面上的“肉刺”
图片来自图片来自
那种密集型的我就不放了·······
这种东西俗称“马牙”，属于雌雄同体物种，成年后将自己粘附在坚硬物体表面。这种看上去类似菊花的东西可一点都温柔，如果长在船体上面，会大幅度加大海行的水流阻力。
但是如果这群“菊花”长在座头鲸或者灰鲸的胸鳍或者尾鳍之上，嘿嘿嘿
嘿嘿嘿
嘿嘿嘿
（下面不建议饭前观看）
那么有一种东西叫做掉血
Photo：© Jim ScarffPhoto：© Jim Scarff
在长达接近5米的巨鳍掌掴之下，任是虎鲸皮糙肉厚，焉有完卵？那感觉就跟在水泥石子路上打球一样，倒下了就很容易被刮层皮！！！
对于寄生的藤壶来说，也有好处，因为在这里寄居，经常有被鳍片卷起的涡流，因而也有充分的食物供应。
一只布满藤壶属种生物的座头鲸：
图片来自图片来自
一只被鲸藤壶附着在头部的灰鲸：
图片来自图片来自
而可怕的是，这种寄生的蔓足类生态群落最高可以重达半吨！！
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以下是答主跟随海岛船出湾拍摄的座头鲸幼崽图片，特别可爱
多图预警，手机渣画质原谅：
头部近距离：
喷孔：喷孔：出水：
背部：背部：玻璃被颜射：玻璃被颜射：跟渔船嬉戏：跟渔船嬉戏： 1/2 1 2 下一页 尾页
