River dolphins have no predators, except for humans. In December 2006 the Yangtze river dolphin, called the baiji, succumbed to pollution, propeller blades, dams, and overfishing; it became the first cetacean to be declared "ally" extinct—meaning the species cannot renew itself, even if a specimen or two still exist. "Losing the baiji is like taking a chain saw to the cetacean tree of life," says Hamilton. "We've lost 20 million years of independent evolution." The Ganges river dolphin is also in grave danger; only a few thousand remain, and they live in some of the most polluted rivers on Earth.淡水河豚没有天敌，除了人类。2006年12月，扬子江河豚，也称白鳍豚，死于水质污染、螺旋桨叶片、水坝以及过度捕捞；第一批功能性“灭绝”的鲸目生物——也就是该物种不能进行自我繁殖了，即使有一两只样本存在。“消失的白鳍豚仿佛锯开了鲸目生物的生命之树。”哈密尔顿说。“我们失去了一段2000万进化历史。”恒河河豚也是岌岌可危。现仅存数千头，生活在地球上污染最严重的水域。

 The Amazon species probably has the best prospects; though its numbers are uncertain, Martin thinks at least 100,000 are left. But the trend is worrisome. At the Mamirauá Reserve, Martin's study population has declined by half over the past seven years. Fishermen hunt dolphins for catfish bait, he says, and they also kill them accidentally in their gill nets.

相比而言，亚马逊河豚算是泡在蜜罐里了。虽然尚未探明准确数量，马丁认为至少有100000只。但是前途也颇让人担心。在Mamirauá R保护区，马丁发现在过去7年里，亚马逊河豚数量已经下降了一半。渔民用鲶鱼引诱河豚上钩，他说，有时他们也张网捕捉。

Once that would have been unthinkable. In Amazonian folk wisdom the boto is an encantado—an enchanted being, a shape-shifter that sometimes takes on human form, coming out of the river to beguile men and women and lead them into its magical underwater city. Some say it wears a hat to hide its blowhole and its bulbous forehead. The stories are incredible to modern ears, and in a way, that's unfortunate. Because to survive in today's world, the boto may need to enchant a wider audience.?

亚马逊河流沿岸流传这样一个民间传说——亚马逊河豚法力无边，有时他能变成人形，从河里走出来，引诱男人和女人，带领他们进入神奇的水下世界。有些人说它戴一顶草帽，是为了隐藏呼吸孔和突出的前额。现代人听到这种传闻，当然不会相信。然而，从某种意义上来说，何曾不是一个悲剧呢。因为为了活下来，河豚或许要借助古老魔法，蛊惑人心。

Amazon dolphins (Inia geoffrensis) bear little resemblance to our beloved Flipper. How'd they get to the Amazon—and why are the males pink?

1/13亚马逊河豚和我们钟爱的鳍状肢动物一点儿都不像。他们是如何来到亚马逊河流——为啥么雄性河豚会是粉色呢？

2/13亚马逊盆地。河豚穿行在发酵的茶色淤泥里和腐烂植物间，看上去闪着橙色光辉。而浮出水面后，他们又恢复了浅灰色，有些是粉色。巴西境内河豚，他们会发出高频率声波，立体定位环境位置。

At a protected inlet where tourists can marvel at their playfulness, two dolphins fight for fish. Though humans are their only predators, rough games, fierce sexual competition, and possibly even maternal discipline leave many Amazon dolphins scarred. Pink skin raked with teeth marks and tattered flukes and fins are badges of male aggression.

3/13在自然保护区入口，游客看到两只河豚为抢食一条鱼，举止幽默，常常惊叹不已。虽然人类才是他们唯一的天敌，但是这种原始游戏，求偶竞争，甚至孕期营养补给，都会给亚马逊河豚伤痕累累。粉色表皮的齿痕，破烂不堪的尾鳍和鳍肢，都是雄性河豚的光荣徽章。

From March to July, the wet-season deluge expands the dolphins' range across inundated plains and into rain forest in the Anavilhanas Archipelago, a vast island chain in the Rio Negro.

4/13 3-7月份的雨季里，洪水淹没平原， Anavilhanas群岛雨林，拓展了河豚的领土。

Botos forage among flooded trees for fish, crabs, and turtles.

5/13 河豚在洪水淹没的树林间抢食鱼，蟹，乌龟。

Fishermen like this one on Brazil's Rio Ariaú use weighted cast nets. Such small-scale, traditional fishing methods are far less hazardous to botos than the growing use of gill nets, which can entrap and quickly kill dolphins.

6/13 巴西里奥·阿里亚乌(Rio Ariaú)渔民用加粗的渔网捕鱼。这种小规模，传统的打渔方法，相比刺网捕鱼，危害性要小得多。

A boto's jaw muscles can snap its elongated beak down on prey with crocodilian ferocity. "It's like an industrial guillotine," says University of Kent biologist Tony Martin.

7/13河豚下颚肌肉发达，能够像鳄鱼般凶狠，“咔嚓”一声咬断长喙下的猎物。“有点像人类的断头台。”肯特大学的生物学家托尼·马丁说。

In an exuberant display of muscle and flexibility, a boto bursts from the floodwaters.

8/13河豚击起千层浪，力量和柔韧性的充分展示。

A male boto makes a pitch for sexual selection by tossing the outsize seed of a rain forest tree. Mating displays include beating the water with branches and river grasses, and "trophy lifting" of live turtles. "It's all to attract the ladies," says University of Kent biologist Tony Martin. "A male will surface repeatedly with an object in his beak and slowly rotate on his own axis." Much of boto life remains largely unfathomable. "We can only guess at the high-frequency singing or trumpeting that probably accompanies these very ritualistic displays," Martin says. "We're still peeping through an aquatic keyhole."

9/13 求偶现场：河豚向上抛起一颗特大号雨林树种。实力展示还包括用树枝和河草击打水面，像捧奖杯一样举起活乌龟。肯特大学的生物学家托尼·马丁说。“雄性河豚会不断地浮出水面，托起东西，慢慢地旋转。”河豚大部分习性，对我们而言，还是深不可测。“但是我们可以推测高声唱歌或者吹响号角，有可能是一种实力展示,”马丁说。“目前我们只能窥见一斑。”

Mother and calf stay close amid drowned saplings. Youngsters nurse for more than a year. Females have just one calf at a time, with two to three years between births.

10/13垂死的树苗间，河豚妈妈和宝宝仅仅偎依在一起。妈妈通常要照顾宝宝长达一年。雌性海豚每2-3年才怀孕一次，每次只有一个宝宝。

Imagined lords of a golden underwater city—the Encante—botos may have been shielded from exploitation by their mythical status.

11/13 黄金水下城的虚拟君主——亚马逊河豚——神秘的民间传说，或许能保护他们，免受人类侵犯。

Today, as rain forests are felled and commercial fisheries move into their hunting range, people are shaping a daunting new world for these river masters.

12/13 如今，热带雨林充斥着大量商业捕鱼队，他们开进河豚的狩猎场，新的游戏规则，新的世界，昔日河上霸主，也是提心吊胆。

This wide-angle shot gives an elongated impression of the stocky boto, hinting at its kinship with whales. Descended from oceanic ancestors, these freshwater dolphins retained powerful cetacean flukes, but streamlined the dorsal fin to a slight ridge. Their adapted body form is well suited to maneuvering in a flooded inland maze of thicket and trees.

13/13 广角镜头拍摄的长喙、矮胖河豚，提示我们它和鲸有亲缘关系。淡水河豚从古代海洋鲸类动物进化而来，仍然保持着强有力的尾鳍，但是其流线型的背鳍只剩一点点脊梁了，以便适合迷宫式热带雨林。