Humanity’s fingerprint can be seen across the planet today， from the towering skyscrapers that define our modern metropolises1 to the pyramids and other ancient monuments of our past. Human activity also marks our sprawling open fields of agriculture and the roads that link everything together. But what would the world look like if humans had never existed？
如今，人类的印记遍布全球，从定义我们现代大都市的高耸摩天大楼，到金字塔和其他古代遗迹。人类活动也体现在广袤的农田和连接万物的道路上。但是，如果人类从未存在过，世界会是什么样子？
Some scientists paint a picture of a pristine wilderness and an abundance of species， from the familiar to the not so familiar. “I think it would be a much more vegetated place with a wealth of animals， of large size spread across all continents except Antarctica，” Trevor Worthy， a paleontologist2 and associate professor at Flinders University in Australia， told Live Science.
一些科学家描绘了一幅原始荒野和物种繁多的图景，从熟悉的到不太熟悉的物种都有。澳大利亚弗林德斯大学古生物学家、副教授特雷弗·沃西告诉趣味科学网站：“我认为那会是一个植被更茂密的地方，有着大量的动物，大型动物遍布除南极洲外的所有大陆。”
Humans have shaped the world at the expense of many species， from the dodo3 to the Tasmanian tiger4， which we drove to extinction through activities such as hunting and habitat destruction.
人类塑造了世界，却以许多物种的消亡为代价。从渡渡鸟到塔斯马尼亚虎，我们通过诸如狩猎和栖息地破坏等活动将它们推向灭绝。
The extinction rate on Earth today is more than 100 times what it would be without humans by the most conservative estimates and hasn’t been higher since the Cretaceous-Paleogene （K-Pg） extinction event5 that wiped out about 80% of animal species， including the nonavian dinosaurs6， 66 million years ago， Live Science previously reported. In other words， humans hit this planet like an asteroid， and the dust is still settling as wildlife continues to decline.
趣味科学网站此前报道，根据最保守的估计，如今地球上的物种灭绝率是没有人类情况下的100多倍，自6600万年前的白垩纪-古近纪灭绝事件以来，灭绝率从未如此之高。在那次事件中，约80%的动物物种灭绝，其中包括非鸟类恐龙。换句话说，人类就像一颗小行星撞击了地球，而尘埃至今未曾落定，野生动物的数量仍在持续减少。
“My great， great grandfather was able to observe flocks of thousands of parakeets7 in the natural landscapes， my grandfather saw flocks of a hundred， my father saw a few and I’m lucky if I can see two in the forests，” Worthy said.
沃西说：“我的高祖父能够在自然景观中看到成千上万只长尾小鹦鹉，我的祖父看到过上百只，我的父亲见过几只，而我能在森林里看到两只就算幸运了。”
The human-led decline of nature indicates that Earth would be a much wilder place without us， with some lost giants， such as moas8， sticking out more than others. This group of ostrich-like birds， some of which stretched up to 11.8 feet （3.6 meters） tall， evolved in New Zealand over millions of years. Within 200 years of humans’ arrival on these birds’ lands 750 years ago， all nine species of moa were gone， along with at least 25 other vertebrate species， including the giant Haast’s eagles9 that hunted the moas， according to Worthy.
人类导致的自然衰退表明，没有我们的地球将是一片更接近荒野的地方，一些已经消失的巨型动物，比如恐鸟，会比其他物种更引人注目。这群形如鸵鸟的鸟类，有些身高可达11.8英尺（3.6米），在新西兰经过了数百万年的演化。沃西称，750年前人类到达了恐鸟的栖息地，在之后的短短200年内，所有9种恐鸟都灭绝了，随之消失的还有其他至少25种脊椎动物，包括体型巨大、以恐鸟为食的哈斯特鹰。
Giant moas and Haast’s eagles are recent examples of large animals whose extinctions are definitively tied to human activities， such as unsustainable hunting and the introduction of invasive species into new habitats. They are also indicators of what our relationship with large animals may have been like elsewhere.
巨型恐鸟和哈斯特鹰是较近历史时期灭绝的大型动物实例，它们以及其他大型动物的灭绝明确与人类活动有关，例如过度狩猎以及将入侵物种引入新的居住地。
