Smaller grazers are still found here, too. But they stay put instead of wandering the plains. Prairie dogs inhabit rambling subterranean towns that stretch tens of square miles. These highly social creatures stay within a short dash of their door, ready to retreat from predators or by weather. It’s always maintenance work to do, but major renovations have to wait until after rain when the soil is soft. All this working and re-working helps the land recover from the impact of so many bigger feet and appetites.
At summer's end, male bison help to move the sun-baked soil as the rutting season starts. They roll in dust and paw the ground to try to dominate their rivals. The dust bath also helps to dislodge irritating insects.
A prairie dog colony is usually surrounded by short, nutritious6 grass, thanks to the many teeth and toe. This constant grazing stimulates fresh growth and also keeps the field of vision clear for spotting predators. Larger neighbours are attracted to these burgeoning meadows, just as they were 13,000 years ago.
1 calves
n.(calf的复数)笨拙的男子，腓;腿肚子( calf的名词复数 );牛犊;腓;小腿肚v.生小牛( calve的第三人称单数 );(冰川)崩解;生(小牛等)，产(犊);使(冰川)崩解
参考例句：
a cow suckling her calves 给小牛吃奶的母牛
The calves are grazed intensively during their first season. 小牛在生长的第一季里集中喂养。 来自《简明英汉词典》
2 herd
n.兽群，牧群;vt.使集中，把…赶在一起
参考例句：
She drove the herd of cattle through the wilderness.她赶着牛群穿过荒野。
He had no opinions of his own but simply follow the herd.他从无主见，只是人云亦云。
3 rambling
adj.[建]凌乱的，杂乱的
参考例句：
We spent the summer rambling in Ireland. 我们花了一个夏天漫游爱尔兰。
It was easy to get lost in the rambling house. 在布局凌乱的大房子里容易迷路。
4 subterranean
adj.地下的，地表下的
参考例句：
London has 9 miles of such subterranean passages.伦敦像这样的地下通道有9英里长。
We wandered through subterranean passages.我们漫游地下通道。
5 predators
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句：
birds and their earthbound predators 鸟和地面上捕食它们的动物
The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
6 nutritious
adj.有营养的，营养价值高的
参考例句：
Fresh vegetables are very nutritious.新鲜蔬菜富于营养。
Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
7 stimulates
v.刺激( stimulate的第三人称单数 );激励;使兴奋;起兴奋作用，起刺激作用，起促进作用
参考例句：
Exercise stimulates the body. 运动促进身体健康。 来自《简明英汉词典》
Alcohol stimulates the action of the heart. 酒刺激心脏的活动。 来自《现代英汉综合大词典》
8 burgeoning
adj.迅速成长的，迅速发展的v.发芽，抽枝( burgeon的现在分词 );迅速发展;发(芽)，抽(枝)
参考例句：
Our company's business is burgeoning now. 我们公司的业务现在发展很迅速。 来自《简明英汉词典》
These efforts were insufficient to contain the burgeoning crisis. 这些努力不足以抑制迅速扩散的危机。 来自辞典例句
