Study Suggests Gorillas Become More Violent in Crowded Forest
研究表明族群增多使大猩猩變得更加暴力
Gorillas are very social animals -- up to a point. Crowded areas can make silverbacks more violent, scientists say.
某種程度上講，大猩猩是喜歡群居的動物。但科學家們表示，擁擠的環境或會導致銀背大猩猩變得更加暴力。
Silverbacks are adult male mountain gorillas that often have a white area across their backs. They are the leaders of gorilla families.
銀背大猩猩是指通常背部有白毛的成年雄性山地大猩猩。他們通常也是大猩猩家族的領袖。
Mountain gorillas are genetically similar to humans. The large animals spend most of their time sleeping, eating, and cleaning each other. They are mostly peaceful creatures.
山地大猩猩的基因與人類相似。這些大型動物大部分時間都在睡覺、吃飯和互相幫助同類清潔毛髮。它們大多是性情平和的動物。
They live in parts of Uganda, the Democratic Republic of Congo, and Rwanda.
它們生活在烏幹達、剛果民主共和國和盧安達的部分地區。
Researchers recently studied 50 years of data from Rwanda. They found that as the number of gorilla family groups increased, so too did the of violent fights between them. Most often, silverbacks led the fights.
研究人員最近研究了盧安達50年來的數據。他們發現，隨著大猩猩家族數量的增加，它們之間的暴力衝突也在增加。銀背大猩猩帶頭互鬥是最常見的情況。
Some gorillas died, especially infants, or babies. These deaths, in turn, slowed population growth.
爭鬥中會造成部分大猩猩死亡，特別是嬰兒或幼兒。這些死亡反過來又減緩了大猩猩數量的增長。
Damien Caillaud of the University of California, Davis, was a co-writer of the new study, published in Science Advances.
加州大學戴維斯分校的達米安·凱勞德是這項新研究的合著者。該研究發表於《科學進展》。
「Males will fight to protect the females and infants in their group, and to acquire new females,」 he said.
他表示：「雄性會為了保護雌性和幼崽而戰鬥，與此同時獲得新的雌性。」
The study found that the amount of fighting was not a result of the total number of individuals in an area. What was important was the number of family groups in an area.
研究發現，爭鬥次數並非某是由當地大猩猩的總數引起的，更為重要的是一個地區族群的數量。
Since the 1960s, mountain gorillas have been carefully studied and protected in central Africa. These animals almost died off in the 1970s. The population has since grown to just over 1,000 animals.
自20世紀60年代以來，非洲中部地區對山地大猩猩進行了仔細的研究和保護。20世紀70年代這些動物差點滅絕。此後它們的數量已經增長至1000多隻。
Rich Bergl is a primatologist at the North Carolina Zoo. Bergl was not involved in the study.
裡奇·伯格是北卡羅來納動物園的靈長類動物學家。伯格沒有參與這項研究。
「Rarely do we think about how an animal’s behavior and social structure can influence population size,」 Bergl said. He added, 「But it turns out we should, especially for social animals like gorillas.」
「我們很少考慮動物的行為和社會結構會如何影響種群的數量，」伯格說道。他還補充道，「但事實證明我們應該這樣做，尤其是對於像大猩猩這樣的群居動物。」
Tara Stoinski was a co-writer of the new paper. She is also president of the Dian Fossey Gorilla Fund, a nonprofit group.
塔拉·斯託因斯基是這篇新論文的合著者。她還是非營利組織迪福斯大猩猩基金的主席。
「Everyone wants to know how many gorillas can live inside the protected habitat area. It turns out the answer depends partly on how they organize themselves socially,」 she said.
她表示：「每個人都想知道保護區內能生活多少只大猩猩。事實證明，在一定程度上答案取決於它們如何構建自己的社會組織。」
While in Rwanda, Stoinski said she saw changes in gorilla behavior beginning about 2007. Around that time, three large family groups broke into many smaller family groups.
斯託因斯基表示，在盧安達她看到大猩猩的行為在2007年左右開始發生變化。大約在那個時候，三個大家庭分裂成了許多小家庭。
The gorilla population grew and families spread out in Volcanoes National Park.
大猩猩的數量增加，各個家庭分散在火山國家公園裡。
There were about 10 family groups in the study area. The number of fights between them increased by three times. The number of infant deaths increased by five times. The population growth fell by half.
在研究區域內大約有10個家族。它們之間爭鬥的次數增加了三倍。嬰兒死亡數量增加了五倍。種群數量的增長率則下降了一半。
The large family groups likely broke apart after the deaths of important silverback leaders, said Stoinski.
斯託因斯基表示，在重要的銀背大猩猩領導去世後，這些大家族可能會分崩離析。
「When these 『elder statesman』 gorillas got older and died, the younger males weren’t able to keep the groups together,」 she said.
她說：「當這些『年長的領導者』大猩猩老去並去世後，年輕的雄性大猩猩無法維持群體的團結。」
The study was based on data from about 400 gorillas in Rwanda between 1968 and 2017.
這項研究基於1968年至2017年間盧安達大約400隻大猩猩的數據。
I’m John Russell.
約翰·拉塞爾報導。