狩獵規(guī)定改變了熊媽媽的養(yǎng)育計劃

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，我們經(jīng)?？吹降暮芏鄤游?，比如野生火雞或者白尾鹿，都是由狩獵者通過努力得以保存的。

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.

同時，在非洲，一些最有代表性的物種已經(jīng)被獵殺至滅絕了。但是狩獵還有一些更微妙的影響。

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.

以棕熊為例(美國稱為灰熊)。當灰熊這類大型哺乳動物被捕獵時，進化機制可能會為他們選擇更快的生命循環(huán)。也就是說，為了在獵殺前成功的繁衍后代，它們會在提早生育。

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

這也會使它們在一生中能夠多次繁衍后代。但是，這并不是灰熊被獵殺時的唯一反應(yīng)。

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.

我們已經(jīng)追蹤檢測瑞典的灰熊數(shù)量大約30年了。斯堪的納維亞的研究人員注意到，雌性灰熊開始改變生育策略，她們會把熊寶寶留在身邊更久。

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.

通常情況下，雌熊會在一月份的時候在巢穴中產(chǎn)下幼崽。但是有些雌熊不再像以往一樣在幼崽一歲半時就給它們斷奶，而是會再繼續(xù)照顧它們一年。

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

也就是說，在棕熊群體中，一些棕熊媽媽在照顧幼崽方面相比以往投入了更多的時間。

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.

研究發(fā)現(xiàn)，自2005年以來，照顧幼崽兩年半的雌熊的比例急劇上升。如今，大約36%的雌熊會這樣做，而在2005年之前這一比例僅為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.

但這一投入顯然是有代價的：隨著照顧幼崽的時間增長，熊媽媽再次生育的時間推遲了。

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

這一變化可以追溯到瑞典狩獵法規(guī)上。法律禁止狩獵攜帶幼崽的雌熊。

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，那些碰巧過度寵愛幼崽的雌熊就不會被射殺--而這也為幼崽提供了足夠的保護和營養(yǎng)養(yǎng)保證。

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

這項研究強調(diào)了不同種類的狩獵規(guī)則會給野生動物帶來不同的影響。

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.

這一認識有助于野生動物管理人員確保野生動物種群的長期生存能力，同時也有保證可持續(xù)捕獵--這本身就是一種保護工具。