而这些数量稀少的老虎分散在13个国家，其中4个国家的虎不再有可繁殖的种群了。
And these are scattered thinly over 13 nations, four of which no longer have viable breeding populations.
它的繁殖速度快得令人难以置信，在条件适宜时，一年可繁殖12代。
It reproduces incredibly quickly, breeding up to 12 generations per year if conditions are favorable.
生存和成功繁殖通常需要动物的活动与周围可预测的事件相协调。
Survival and successful reproduction usually require the activities of animals to be coordinated with predictable events around them.
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