揭开绵羊软弱外表下的真面目

编辑:给力英语新闻 更新:2018年1月13日 作者:哈莱特·康斯坦博尔(Harriet Constable)

在人们印象中,绵羊是一种智力低下、无防卫能力、人畜无害的动物,喜欢在山坡上游荡。它们对人类有两个贡献:提供羊肉和羊毛。

但实际上,绵羊却拥有惊人的智商,其记忆和认知能力也非常突出。它们相互之间能产生友谊,在争斗时相互保护,当朋友被送去屠宰时会感到难过。与此同时,它们也是地球上最具破坏力的动物之一。

聪明、复杂、好交际,所有这些单词都是用来描述我们人类的,人们做梦也想象不到这些词也同样适用于绵羊——那些毛发蓬松、浑身洁白的动物。当它出现在你的眼中时,它们要么整天在田间游荡,要么它的肉摆在在你的餐桌上。

相反,我们在历史上早就认定绵羊是一种愚不可及的动物。自18世纪初叶以来,这一观点一直没有改变。例如,美国国父乔治·华盛顿曾经说过:"如果被剥夺了言论自由,我们就会变得愚笨和沉默,像绵羊一样被拉向屠宰场。"

绵羊
人类饲养绵羊已有数千年历史(图片来源: Radius Images/Alamy)
Sheep have been farmed for millennia

如今,知名在线俚语词典——《城市词典》(Urban Dictionary)的词条上说,说某人像"一只绵羊",就是说他盲目跟从他人,在"浪费生命和脑细胞"。

然而,事实却是,绵羊比我们想象的要聪明得多。

绵羊
绵羊对周边环境具有巨大影响力(图片来源: Tim Gainey/Alamy)
Sheep have a powerful influence on their environment

英国生物学会会员、目前在中国电子科技大学(University of Electronic Science and Technology in China)任教的基斯·肯德里克(Keith Kendrick) 2001年发布的一项研究发现,绵羊可以辨认和记住至少50张不同的面孔,记忆时间可以超过2年。这一时间比许多人的记忆时间还长。

在研究中,肯德里克的团队训练绵羊在25对绵羊中辨认每对中的一只绵羊,当辨认正确时就会得到食物奖励。

肯德里克称:"绵羊明显表现出了个体识别能力:当看到不同绵羊的脸部照片时,受试绵羊会发出不同的叫声,"肯德里克说。该团队还发现了绵羊能够区分面部表情的证据:它们喜欢微笑和皱眉等表情。

当时,肯德里克在接受BBC新闻采访时称:"绵羊大脑的组织方式表明,它们对它们看到的世界一定会产生某种情绪反应。"

澳大利亚联邦科学与工业研究组织(CSIRO)的卡洛琳·李(Caroline Lee)也对绵羊智商开展了研究。她发现,绵羊能学会如何从复杂的迷宫中走出来。实验人员在迷宫终点布置了另一只绵羊,受试绵羊在看到终点绵羊所在位置后最终到达了迷宫的出口。

除了具备高超智力,绵羊还会玩耍和体验快乐。你要是看过绵羊在床上蹦跳的著名视频,就一定不会否认这一点。绵羊也存在性偏好:有8%的绵羊是同性恋,绵羊是对同性伴侣有终生偏好的少数物种之一。

绵羊群落存在复杂的社会结构。

牧羊人与羊
一幅描绘牧羊人与羊的雕刻作品(图片来源: FromOldBooks.org/Alamy)
An engraving of a shepherd with his sheep

20多年前,加州大学研究人员对公羊进行了长达三年的观察,发现它们之间能建立深厚的友谊,并在需要的时候彼此帮助。这份写于1993年的研究报告称:"我们发现,公羊之间形成了长期关系,当较弱的同伴受到欺负时会插手,并在打斗时相互支持。"

这些忠诚和友谊行为是受到情绪驱动的举动。国际爱护动物基金会(简称IFAW) 2009年发布的一份报告表明,绵羊能够体验一系列感情:恐惧、愤怒、绝望、无聊和幸福等。

研究人员让绵羊间歇性地从槽中获取食物,然后在它们享用食物时突然打开食槽上方的鼓风机。鼓风机打开后,绵羊发出咩咩叫声的次数是未受干扰情况下的四倍多,同时它们的心率也立即升高。

该研究报告的作者表示:"与人类一样,绝望是由突然、不熟悉、不可预测……不可控制的状况所引发的,而无聊则来自高度可预测的环境。"

人们突然之间发现,绵羊似乎不像以前想像的那么愚蠢。

欧洲盘羊
欧洲盘羊,一种野生绵羊(图片来源: Prisma by DukasPresseagentur GmbH/Alamy)
A mouflon, a species of wild sheep

讽刺的是,尽管绵羊已经深深扎根于人类文化中,但实际上我们大多数人都对这种动物知之甚少。早在公元前11,000-9,000年间,绵羊就已被人类驯养以利用它的毛、肉和奶。数千年来,这种动物频繁地出现在不同的文化、宗教甚至占星术中。

例如,希腊星座——白羊座的标志是一只公羊;在古埃及宗教中,公羊是好几位神灵的象征。此外,俗语"把绵羊和山羊分开"来自《新约》中的一段文字。故事中,绵羊(代表好人)受到上帝的救赎,而山羊(代表罪人)则受到惩罚堕入地狱。

科学家认为,绵羊是曾在欧亚两洲分布的野生盘羊的后代。这种野生盘羊在古代美索不达米亚(Mesopotamia)地区数量极多,该地区位于目前中东地区的腹地,包括现在的伊拉克、科威特、叙利亚东部和土耳其东南部地区。

野生盘羊拥有一对粗壮的弯角来保护自己。如今,经过品种改良的家养绵羊是一种毛发蓬松的动物,覆盖全身的羊毛能够不停生长,终年为农民赚钱。

今天的绵羊仍然保持着一些生存技巧。

(图片来源: RooM the Agency/Alamy)
绵羊柔顺的双眼后面隐藏着惊人的智力(图片来源: RooM the Agency/Alamy)
There is surprising intelligence behind these eyes

陌生人如果离绵羊距离过近,会被它恨恨地踢上一脚,特别是在它需要保护小羊的时候。绵羊在悬崖峭壁上快速奔跑攀登如履平地,许多猎食动物对此只能望洋兴叹。另外,它们还拥有宽广的视野:它们长着狭缝形的水平瞳孔,无需转头就能看到自己的后面。

然而,这些自我防卫手段在人类面前全都不值一提。

联合国粮农组织提供的数据表明,人类非常喜欢吃羊肉,穿羊毛制品……根据粗略估算,目前地球上大约存栏12亿只绵羊。

世界上最大的绵羊生产国中国存栏近2亿只绵羊。其次是澳大利亚,存栏7,000多万只。印度有6,000多万只,伊朗拥有4,500万只,尼日利亚有4,100万只。苏丹有近4,000万只,英国有3,300万只,新西兰接近3,000万只。

肯尼亚估计有1,700多万只肉用绵羊。在这个国家,大规模饲养绵羊对野生动物造成了灾难。

白大角羊
白大角羊是一种野生绵羊(图片来源: Design Pics Inc./Alamy)
Dall sheep are a species of wild sheep

2016年9月发表的一份研究报告显示,1977年至2016年期间,肯尼亚野生动物的数量减少了68%。数量下降的物种有疣猪、多种羚羊和稀有的细纹斑马等。同期,该国的绵羊存栏量则增加了76.3%。

该研究报告的第一作者是德国斯图加特霍恩海姆大学(University of Hohenheim)的约瑟夫·奥古图(Joseph Ogutu)。他指出,肯尼亚政府组织的空中监测显示,过去40年来,该国绵羊数量急剧上升。他说:"绵羊啃食野草时,会把露出地面的草茎几乎啃光。当绵羊数量庞大时,它们会把整片草地破坏掉。大多数野生动物(如大象、水牛和斑马)都需要吃长得较高的草,因此绵羊泛滥造成的后果极为严重。"

奥古图称,在肯尼亚的马赛马拉国家野生动物保护区,1992年野生水牛的数量接近1.3万头,但现在它们的数量已经急剧下降。他说:"干旱期间,野生水牛都会被家养牛羊从适宜觅食的区域驱赶出去。仅在一年当中,野生水牛的数量就下滑了76%,从此以后再没有恢复过来。"

干旱在肯尼亚经常发生,但现在最大的问题在于:需要在旱灾中生存下来的野生和家养动物数量加起来极为庞大。奥古图表示:"现在,许多绵羊正在与野生动物争夺有限的的资源,干旱则让这种竞争的后果更为惨烈。"

白大角羊
家养绵羊的近亲白大角羊(图片来源: Ron Niebrugge/Alamy)
A Dall sheep (Ovis dalli), a relative of the domestic sheep

奥古图和他的同事正在呼吁肯尼亚政府限制绵羊和其它牲畜的数量,从而防止大型野生动物出现灭绝。

肯尼亚只是全球性危机的一个缩影。随着人类对畜产品的需求不断上升,牲畜对环境造成的压力也越来越大。

联合国粮农组织2006年发布的一份报告对此做了解释:"大规模放牧占据了大片土地,并且造成土壤贫瘠……畜牧业直接争夺稀缺的土地、水和其它自然资源……总的来说,畜牧生产占据了70%的农业用地和30%的地球表面。"

当数量巨大时,绵羊是一种具有极大破坏性的动物。人类大规模饲养绵羊是造成森林破坏、气候变化、淡水匮乏的原因之一。

当然,这很难说是绵羊自己的过错。但是每当你想到这点,它们也就不那么呆萌可爱了。

Sheep are not stupid, and they are not helpless either

Reputation: Sheep are stupid, defenceless and harmless creatures that mope about on hillsides doing not very much. They are good for two things: being eaten and producing wool.

Reality: Sheep are actually surprisingly intelligent, with impressive memory and recognition skills. They build friendships, stick up for one another in fights, and feel sad when their friends are sent to slaughter. They are also one of the most destructive creatures on the planet.

Intelligent. Complex. Sociable. All words we would quickly assign to humans, but would not dream of extending to sheep, those fluffy white creatures you see milling about in fields – or served up with mint sauce on your dinner plate.

Instead, we have decreed that sheep (Ovis aries) are just plain stupid. This opinion has not changed much since the 1700s, when George Washington, one of the Founding Fathers of the United States of America, declared: "If the freedom of speech is taken away then dumb and silent we may be led, like sheep to the slaughter."

Nowadays, to be "a sheep" is to be someone who mindlessly follows others: "a waste of flesh and brain cells," as Urban Dictionary puts it.

The truth is that sheep are far smarter than we know.

A 2001 study by Keith Kendrick, who is now at the University of Electronic Science and Technology in China, found that they can recognise and remember at least 50 individual faces for more than 2 years. That is longer than many humans.

In the study, Kendrick's team trained sheep to distinguish between 25 pairs of sheep, by associating one member of each pair with a food reward.

Sheep also have erotic preferences: 8% are homosexual

"Sheep showed clear behavioural signs of recognising… individuals by vocalising in response to their face pictures," says Kendrick. The team also found evidence that sheep can differentiate facial expressions, and prefer a smile to a frown.

At the time Kendrick told BBC News: "The way the sheep's brain is organised suggests they must have some kind of emotional response to what they see in the world."

Caroline Lee of the CSIRO in Australia has also studied sheep intelligence. She discovered that sheep can learn how to navigate out of a complex maze. The enticing sight of their fellow sheep friends awaiting them at the finish helped them reach the exit.

Aside from being smart, sheep can be playful and joyful. You only need to watch the video of Winter the Jumping Lamb to see for yourself. Sheep also have erotic preferences: 8% are homosexual, making them one of the few species that show lifelong preferences for same-sex partners.

Sheep also have complex social structures.

Over two decades ago, researchers from the University of California observed rams for three years and discovered that they established firm friendships and looked out for one another in times of need: "Rams were found to form long term relationships… [they] intervened on behalf of weaker colleagues and supported each other in fights," says the 1993 study.

They were domesticated between 11000 and 9000 BC for the use of their woollen fleece, meat and milk

These acts of loyalty and friendship-building are driven by emotions. A 2009 report published in Animal Welfare found that sheep are capable of experiencing a whole range of feelings, from fear to anger, despair, boredom and happiness.

The researchers gave sheep intermittent access to food from a trough, and then turned on an air blower above the trough at an unexpected moment while they were eating. After the blower came on, the sheep bleated four times more than sheep that were not disturbed, and their heart rates immediately increased.

"[As with humans], despair is triggered by situations which are evaluated as sudden, unfamiliar, unpredictable… and uncontrollable, whereas boredom results from an overly predictable environment," write the authors.

Suddenly sheep do not seem so dumb after all.

It is ironic how little most of us know about sheep, given how deeply entrenched they are in human culture. They were domesticated between 11000 and 9000 BC for the use of their woollen fleece, meat and milk. The animals have been referred to by different cultures, religious texts and even astrology for thousands of years.

They can deliver a painful kick to anyone who gets too close

For example, the Greek astrological sign Aries is a ram, and in ancient Egyptian religion the ram was the symbol of several gods. Further, the common phrase "to separate the sheep from the goats" comes from a passage in the New Testament. In the story, the sheep (righteous people) find salvation with God, and the goats (sinners) are sent to damnation. Baad goats.

Sheep are thought to have descended from wild mouflon that roamed Europe and Asia. They were particularly common in ancient Mesopotamia, an area that covered a large chunk of what we now call the Middle East, including modern-day Iraq, Kuwait, east Syria and south-east Turkey.

These ancestors had mighty horns with which to defend themselves, but humans have largely bred these out of modern sheep. Nowadays, domestic sheep are bred to be big fluffy creatures, covered in wool that never stops growing so that farmers make money all year round.

However, today's sheep still have a few tricks up their woolly sleeves.

For starters, they can deliver a painful kick to anyone who gets too close, especially if they are defending their young. They can also run fast and scale steep cliffs that many predators are not equipped to handle. Finally, their peripheral vision is impressive: they have horizontal, slit-shaped pupils that allow them to see behind themselves without turning their heads.

The populations of wild animals in Kenya fell by 68% between 1977 and 2016

Still, none of these defences are a match for us.

Humans very much like to eat and wear sheep: so much so that there are 1.2 billion sheep on the planet, according to data from the UN Food and Agriculture Organization.

The world's biggest producer of sheep is China, which is home to nearly 200 million of them. It is followed by Australia at over 70 million, India with over 60 million, Iran with 45 million and Nigeria with 41 million. Sudan has nearly 40 million sheep, while the UK has 33 million and New Zealand nearly 30 million.

In Kenya, where there are estimated to be over 17 million sheep raised for slaughter, the animals are spelling catastrophe for wildlife.

A study published in September 2016 shows that the populations of wild animals in Kenya fell by 68% between 1977 and 2016. The affected species included warthogs, many species of antelope and the rare Grevy's zebra. During the same period, sheep numbers increased by 76.3%.

The effects of drought are much more extreme now

"Aerial monitoring from the government of Kenya shows that sheep numbers have gone up dramatically in the last 40 years," says lead author Joseph Ogutu of the University of Hohenheim in Stuggart, Germany. "Sheep graze grass very low to the ground, and in their huge numbers they decimate the grasslands. This is terrible because most wild animals [like elephants, buffalo and zebra] need taller grasses to eat."

In the Maasai Mara National Reserve, Ogutu says the buffalo population was nearly 13,000 in 1992, but has since sharply decreased. "During the drought, they were pushed out of feeding areas by sheep and other cattle, and the buffalo population crashed by 76% in one year. They've never recovered."

Drought is not uncommon in Kenya, but the issue now is the number of animals, both wild and domesticated, trying to survive it. "The effects of drought are much more extreme now that there are so many sheep competing with wild animals for the same resources," says Ogutu.

Ogutu and his colleagues are calling on the Kenyan government to limit the number of sheep and other livestock, to prevent large wild animals going extinct.

In their huge numbers, sheep are hugely destructive creatures

But what is happening in Kenya is a microcosm for a global story. The demand for livestock products is still rising, putting pressure on the environment.

A 2006 report by the UN Food and Agriculture Organisation explains why: "Extensive grazing occupies and degrades vast areas of land… the livestock sector enters into more and direct competition for scarce land, water and other natural resources… in all, livestock production accounts for 70 percent of all agricultural land and 30 percent of the land surface of the planet."

In their huge numbers, sheep are hugely destructive creatures. Our use of them is contributing to the destruction of forests and to climate change, and causing a shortage of fresh water.

Of course, it is hardly the fault of the sheep. But somehow they do not seem quite so dumb and cuddly any more.