猫不是群居动物 原因在哪?
猫不是群居动物 原因在哪?
How hard can it really be to herd cats?
让猫群居生活有多难?
Ask Daniel Mills, professor of veterinary behavioural medicine at the University of Lincoln, UK. In a recent study, Mills and his colleague Alice Potter demonstrated that cats are more autonomous and solitary than dogs. Carrying out the research for the project was as difficult as the cat's reputation might suggest.
不妨请教英国林肯大学(University of Lincoln)行为兽医学教授丹尼尔·米尔斯(Daniel Mills)。丹尼斯和他的同事爱丽丝·波特(Alice Potter)在最近的一项研究中证明猫比狗更喜欢自主和独自的状态。猫的这种名声预示这个研究项目会很难进行,事实也正是如此。
"They are challenging if you want them to do certain things in a certain way," says Mills. "They tend to do their own thing."
"很难想让猫以你想要的方式来做某些事情,"米尔斯说,"它们倾向于做自己的事。" Cat owners everywhere will sympathise. But why exactly are cats so reluctant to cooperate, either with each other or with a human? Or to flip the question around, why are so many other animals – wild and domestic – willing team players?
任何地方的养猫的人都会有同感。但是为什么猫不愿意互相配合,或者与人类配合?或者,换个角度来问,为什么那么多其他的动物——不论是野生还是家养——都愿意群居(作为团队中的一分子)呢?
Group living is very common in nature. Birds flock, wildebeest herd, fish school. Predators often hunt together too, of course. Even the domestic cat's relative, the lion, lives in a pride.
群居是自然界的一种常见形式。鸟类、野兽、鱼类都会群居。食肉动物也常常一起捕猎。连家猫的近亲狮子也是群居动物。
For prey species there is an obvious "safety in numbers" element to the strategy. "It's called the dilution effect," says biologist Craig Packer of the University of Minnesota in St Paul. "A predator can only take one, and if there's a hundred of you that reduces your chances down to 1%. Whereas if you're by yourself, you'll be chosen 100% of the time."
对于被捕猎的物种来说,其生存战略带有明显的"数量安全"的元素。"这被称为稀释效应,"位于圣保罗(St Paul)的美国明尼苏达大学的生物学家克雷格·帕克(Craig Packer)说,"如果肉食动物只能抓到一只,如果一百只在一起,那么对每个单体来说概率就减少到1%。而如果单独生存,被抓到的概率就是100%。"
Animals in herds also benefit from the "many eyes" effect: the larger the prey group, the more likely they are to detect an approaching predator. "And the earlier you can detect the predator, the more time you have to initiate avoidance behaviour," says Jens Krause of Humboldt University in Berlin, Germany.
群居动物还得益于"多眼"效应:被捕猎动物的群体越大,它们就越有可能发现靠近它们的天敌。"越早发现天敌,就有越多的时间开始躲避,"德国柏林洪堡大学(Humboldt University)的简斯·克劳斯(Jens Krause)说。
This collective vigilance brings other advantages. Individuals can afford to spend more time and energy looking for food.
集体警戒还有其他好处。个体能分配更多的时间和能量寻找食物。
It is not all about avoiding predators, though. Animals that socialise in groups do not have to roam around for a suitable mate, which is a problem for solitary species that cover large territories. It is clearly much easier just to look to the herd for a date.
这不只是关于躲避天敌。群居动物步需要去远方寻找合适的伴侣。这对在宽广地区单独生活的物种来说是一个问题。显然在群体中寻找伴侣简单的多。
And once they have produced their offspring, many group-living animals live by the "it takes a village" maxim: adults may work together to protect or feed the young.
而一旦它们产下幼崽,很多群居动物遵守"群养"法则:成年动物会协作保护或喂养幼崽。
In many bird species, such as the Arabian babblers of Israel, young birds remain in family groups until they are ready to mate. They dance in groups, bathe in groups, and even present each other with gifts.
对很多鸟类来说,比如以色列的阿拉伯鸫鹛(Arabian babblers),幼鸟会留在族群中直至它们准备好交配。鸟群一起飞舞,一起沐浴,甚至互送礼物。
There are also energy savings to be made from group living. Birds that flock together or fish that school move more efficiently than solitary fliers and swimmers.
群居还能节约体能。鸟群或鱼群的移动效率高于单独飞行的鸟或单独游动的鱼。
It is the same principle that Tour de France cyclists use when they form a peloton. "The ones that are further back, they don't have to invest quite as much energy for the same speed of locomotion," says Krause.
环法自行车赛的选手们也利用相同的原则聚集在一起。"靠后的选手达到同样的速度所需的体能较少,"克劳斯说。
Finally, as both bats and emperor penguins can testify, it can be just plain warmer when you huddle up to friends.
最后,蝙蝠和帝企鹅都可以证明,和你的朋友聚在一起会暖和一些。
With so many benefits, it might seem surprising that any animal would shun its peers. But, as domestic cats show, group living is not for everyone. For some animals, sharing food just is not worth the benefits of being in a group.
既然群居的好处那么多,远离同类的动物似乎就让人感到惊讶。但是,正如家猫所示,群居不是普遍现象。对一些动物来说群居的好处无法弥补分享食物的缺点。
"When you're feeding together, there's a point at which feeding with other individuals in close proximity reduces your intake," says John Fryxell, an integrative biologist at the University of Guelph in Canada.
"当它们一起进食时,达到一定程度后,和其他同类一起进食就会减少个体的食物数量,"加拿大圭尔夫大学(University of Guelph)的整合生物学家约翰·弗里克塞尔(John Fryxel)说。
A key factor then becomes whether each animal has sufficient food, which in turn depends on how much food each animal needs. And cats have expensive tastes. For instance, a leopard will chew its way through 50lb (23kg) of meat every few days. Typically, for wild cats, the competition for food is fierce, so leopards live and hunt alone.
那时,关键的因素就变成了每只动物能否获得足够的食物,这又取决于每只动物所需的食物。猫科动物的食量很大。以豹为例,一只豹每隔几天就要吃掉23公斤的肉。通常,野生猫科动物之间对食物的竞争非常激烈,所以豹独自生活,独自捕猎。
There is one exception to this solitary cat rule: lions. For lions it is a territorial deal, says Packer, who has spent nearly five decades studying African lions. Certain locales in the savannah grasslands offer perfect ambush spots for prey, so controlling that prime real estate offers a significant survival advantage. "It imposes sociality because you have to have teams to dominate your local neighbourhood, exclude competing teams, and the biggest team wins," Packer says.
猫科动物独居法则的唯一例外:狮子。对狮子来说,这是一种地盘交易,帕克说。帕克花了近50年的时间研究非洲狮。大草原中有一些地方是伏击猎物的绝佳位置,所以控制这些有利位置能够带来很大的生存优势。"狮子被迫结为团队,以控制自己的领地,驱逐竞争的团队。胜利属于最大的团队,"帕克说。
What makes this happy hamlet possible is that a single lion kill – a wildebeest or zebra – is large enough to feed several females at once. "So the size of the prey allows them to live in groups, but it's the geography that really drives them toward living in groups," Packer says.
狮群之所以成为可能,是因为一只狮子捕猎的成果——一只角马或斑马——足够一次喂饱多只母狮。"它们捕猎的规模让群居成为可能,但真正驱使它们群居的原因是地盘意识。"
This is not a situation domestic cats find themselves in, because they hunt small animals. "You don't want to be around somebody else when they've just caught a mouse, because they're going to eat it whole," Packer says. "It's gone. There is not enough food to share."
家猫的处境就不一样了,因为它们捕猎小动物。"当猫刚抓到一只老鼠时,它不想周围有其他的猫,因为它会把老鼠整个吃掉,"帕克说,"食物会吃完,不足以分享。"
This sort of economic reasoning is so deeply engrained in cat behaviour, it seems unlikely that even domestication could have altered this fundamental preference for solitude.
这种经济学思维潜藏在猫的行为中。甚至畜养的过程也未能改变这种独居的基本倾向。
This is doubly true when you consider that humans did not domesticate cats. Instead, in true cat style, cats domesticated themselves.
另外一个证据就是人类并没有驯化猫,实际上是猫驯化了它们自己。
All domesticated cats are descended from Middle Eastern wildcats (Felis silvestris), the "cat of the woods". Humans did not coax those early cats out of the woods; the cats invited themselves into our grain storehouses, where an abundance of mice fed unchecked. Gate-crashing this mouse party marked the start of a truly symbiotic relationship. The cats loved the well-stocked storehouses, and the people appreciated the pest control.
所有家猫都源于中东的野猫,也被称为"林猫"。人类并没有诱骗这种猫走出树林;相反,是这些猫不请自来,到人类的谷仓里捕食大量的老鼠。它们擅自闯入老鼠的聚会,而这就是人与猫共同生活的开始。猫喜欢谷仓,人希望控制鼠患。
Domestic cats are not entirely antisocial. But their sociability – to one another or to their human owners – is handled entirely on their terms.
家猫并不是完全反对社交。但是它们的社交能力——彼此之间或与主人——完全由它们自己做主。
"They retain a large degree of independence and approach, or stay close to us, only when they want to," says Dennis Turner, a cat expert and animal behaviourist at the Institute for Applied Ethology and Animal Psychology in Horgen, Switzerland.
"它们在很大程度上保留了独立性,只在需要时接近我们,或和我们呆在一起,"瑞士豪尔根(Horgen)应用动物行为学和动物心理学研究所的猫科动物专家、动物行为学家丹尼斯·特纳(Dennis Turner)说。
"Cats have evolved lots of mechanisms to keep themselves apart, which aren't exactly conducive to herding," says Mills. Cats spray their territory to help avoid awkward meetings with each other. If they do accidentally come face to face, the hackles rise and the claws come out.
"猫进化出了很多与其他猫保持距离的机制,这并不有助于群居,"米尔斯说。猫在自己领地周围撒尿,以避免与其他猫尴尬碰面。如果它们不小心碰到,它们就会竖起毫毛,伸出爪子。
If cats will not stop fighting, they are unlikely to start herding.
如果猫不停止争斗,它们就不太可能开始群居。
In some circumstances it can appear that domestic cats have embraced group living; for instance, a colony living in a barn. But do not be fooled, says Fryxell.
在一些情况下,家猫看似愿意群居。比如,住在谷仓的一些猫。但是不要被骗了,弗里克塞尔说。
"They're very loose aggregations and they don't have any real group identity," he says. "They just have a common place they come to keep their kittens."
"它们之间的关系非常松散,而且它们没有任何群体身份,"他说,"它们就是有一个共同的空间可以让它们来照顾自己的小猫。"
In fact, even in the face of extreme danger, which often brings animals together to form a defensive unit, it is unlikely cats would cooperate. "It's just not something that they typically do when they're threatened," says Monique Udell, a biologist at Oregon State University. Cats just do not believe in strength in numbers.
事实上,即使在极端危险的情况下,猫也不太会合作,通常其他动物会联合形成一个防御单位。"当它们受到威胁时,它们通常也不会做这样的事,"俄勒冈州立大学的生物学家莫妮克·尤德尔(Monique Udell)说。猫不相信数量能够带来力量。
All of this helps explain why cats have a reputation for being impossible to herd. Even so, there is some evidence that the domestic cat's disdain for group living could be weakening.
所有这些都有助于解释为什么猫不可能群居。即便如此,还是有一些证据表明猫对群居的厌恶有可能在减弱。
A study published in 2014 in the Journal of Comparative Psychology saw scientists probe the personality traits of domestic cats. In keeping with their solitary, uncooperative reputation, cats turned out to be neurotic, impulsive and resistant to being ordered around.
2014年《比较心理学》期刊(Journal of Comparative Psychology)上发表了一项研究。其中,科学家探究了家猫的个性特点。猫具有神经质、冲动、抗拒接受命令的个性,这符合它们独来独往、不合作的名声。
Interestingly, though, domestic cats might be a little less uncooperative than their wild relatives. When the researchers compared the domestic cat to four wild cats – Scottish wildcats, clouded leopards, snow leopards and African lions – the domestic cats proved to be most like those group-living lions in terms of their overarching personalities.
有趣的是,家猫的不合作性格与野生猫科动物较弱。研究者把家猫和四种野生猫科动物进行比较——苏格兰野猫、云豹、雪豹和非洲狮——在整体个性方面,家猫与群居的狮子最相近。
It is also fair to say that domestic cats have come a long way from their ancestors in terms of tolerating each other's company. Although groups of cats living in barns form loose aggregations at best, they still show a remarkable level of acceptance for each other's presence in such confined spaces.
公平而论,家猫在忍受彼此的陪伴方面与它们的祖先相比已经有了长足的进步。尽管一起住在谷仓里已经是它们的极限,然而它们在这种有限的空间里还是表现出了互相接受的能力。
In Rome, nearly 200 cats live side-by-side in the Colosseum, while on Aoshima Island in Japan cats outnumber people six to one. These colonies may not be cooperatives, but they are a far step from the domestic cat's solitary past.
罗马斗兽场里有近200只猫一起生活,而在日本爱媛县的青岛(Aoshima),猫与人的比例是6比1。这些猫在一起未必会合作,但是与家猫孤独的过去相比,已经是迈出了巨大的一步。
Researchers, meanwhile, might find it easier to control the cats in their experiments by meeting them halfway.
与此同时,研究者通过实验发现,适当妥协就可以轻松控制猫。
When Udell performed her early experiments on cats, she encountered a lot of difficulties trying to motivate her subjects to engage in the task at hand. She had previously worked with dogs, which would willingly perform any task repeatedly for a food reward. But cats were not so easily pleased. Eventually, Udell started having success when she began giving cats the option of choosing what their reward was.
尤德尔在早期实验中遇到了很多困难,她很难让猫进行手边的任务。此前,她曾做狗的实验,只要有食物奖励,狗就愿意反复完成任何任务。但是猫没那么容易讨好。最后,尤德尔让猫选择奖励的内容,实验才得以继续。
"I think that part of the challenge is just how much we understand about cats," she says. If scientists start to gain insights into the black box of the feline mind, herding by force could give way to convening cats using cunning coercion.
"我认为部分的挑战是我们对猫的了解不够,"她说。如果科学家开始了解猫的大脑,那么就可以利用狡猾的强制方法取代强迫群养的方法。
Much of animal behaviour – including an affinity or resistance to herding – lies deep in a creature's neural circuitry. It is difficult to ever imagine circumventing years of natural selection, Fryxell says.
动物的很多行为——包括愿意或抗拒群居——植根于神经回路。光是想象规避长年的自然选择就已经十分困难。弗里克塞尔说。
"But who knows? Obviously, lions managed the feat, so it must be possible for the proper set of mutations to occur," he says. "And if they managed to pull off the trick, maybe [herding cats] is not that crazy an idea, after all."
"但谁知道呢?显然,狮子掌握了这一技巧,所以一定有可能通过一连串适当的突变完成这一转变,"他说,"如果他们能够施展这一魔法,那么让猫成为群居动物或许就不是什么疯狂的想法。"