狩猎规定改变了熊妈妈的养育计划

In North America, many critters commonly encountered today -- like wild turkeys or white-tailed deer -- were brought back from near oblivion through conservation efforts led by hunters.

在北美，我们经常看到的很多动物，比如野生火鸡或者白尾鹿，都是由狩猎者通过努力得以保存的。

Meanwhile, in Africa, some of the most charismatic species are now being hunted into extinction. But hunting can also have impacts that are far more subtle.

同时，在非洲，一些最有代表性的物种已经被猎杀至灭绝了。但是狩猎还有一些更微妙的影响。

Take the brown bear, known here in the U.S. as the grizzly. When large mammals like grizzlies are hunted, evolution might select for speedier life cycles. That is, in order to successfully reproduce before they risk getting shot, bears might begin having cubs at a younger age.

以棕熊为例(美国称为灰熊)。当灰熊这类大型哺乳动物被捕猎时，进化机制可能会为他们选择更快的生命循环。也就是说，为了在猎杀前成功的繁衍后代，它们会在提早生育。

That change also allows them to reproduce more times throughout their lives. But that's not the only possible reaction to being hunted.

这也会使它们在一生中能够多次繁衍后代。但是，这并不是灰熊被猎杀时的唯一反应。

The brown bear population in Sweden has been monitored for about 30 years. And researchers in Scandinavia have noticed that females started to change their reproductive strategies. They would observe that females would keep their cubs for longer periods of time nowadays.

我们已经追踪检测瑞典的灰熊数量大约30年了。斯堪的纳维亚的研究人员注意到，雌性灰熊开始改变生育策略，她们会把熊宝宝留在身边更久。

Usually females give birth in January while in their den. But some females, rather than weaning their cubs after one year and a half, continue to care for them for an extra year.

通常情况下，雌熊会在一月份的时候在巢穴中产下幼崽。但是有些雌熊不再像以往一样在幼崽一岁半时就给它们断奶，而是会再继续照顾它们一年。

So some brown bear mothers in this population began to spend more time, not less, caring fortheir cubs.

也就是说，在棕熊群体中，一些棕熊妈妈在照顾幼崽方面相比以往投入了更多的时间。

And we have seen that since 2005, the proportion of females that keep their cubs for twoyears and a half has increased dramatically. Nowadays, its about 36 percent of females that usethat tactic, whereas before 2005, it was about only 7 percent or so.

研究发现，自2005年以来，照顾幼崽两年半的雌熊的比例急剧上升。如今，大约36%的雌熊会这样做，而在2005年之前这一比例仅为7%左右。

But that increased investment comes at a cost: by spending more time with their cubs, it takes longer before the mothers reproduce again.

但这一投入显然是有代价的：随着照顾幼崽的时间增长，熊妈妈再次生育的时间推迟了。

And the change can be traced to Swedish hunting regulations. The law prohibits killing females if they are accompanied by cubs.

这一变化可以追溯到瑞典狩猎法规上。法律禁止狩猎携带幼崽的雌熊。

So females that happen to have the urge for extra maternal care don't get shot -- and this also gives the youngsters protection and guaranteed nutrition.

因此，那些碰巧过度宠爱幼崽的雌熊就不会被射杀--而这也为幼崽提供了足够的保护和营养养保证。

The study underscores how different kinds of hunting regulations can lead to different out comes for wild animals.

这项研究强调了不同种类的狩猎规则会给野生动物带来不同的影响。

This kind of knowledge helps wildlife managers ensure the long-term viability of wild life populations, while also allowing for sustainable hunting -- which itself can be a conservation tool.

这一认识有助于野生动物管理人员确保野生动物种群的长期生存能力，同时也有保证可持续捕猎--这本身就是一种保护工具。