These youths are full of animal spirits.

（誤譯）這些年輕人充滿動物精神。
（正譯）這些年輕人充滿活力。

animal spirits 精力充沛
類似表達如下：

1. full of energy

You are strong and full of energy.
你身強體壯，充滿活力。

That old man remained full of energy.
那位老人還是那么精力充沛。

After rests, we are full of energy to go down quickly.
經過短暫的休息討論后，大家的精力都很旺盛，下山速度明顯加快。

2. as fresh as paint 精神飽滿的

The children looked as fresh as new paint after their bath.
孩子們洗完澡后顯得精神煥發。

Though nearly seventy years of age, he is still hale and fresh as paint.
他雖年近七十，但身子硬朗，精力充沛。

After living a while in the open, campers become as fresh as paint. They feel rejuvenated.
經過一段時間的野外生活，露營者變得精神飽滿，感到恢復了青春的活力。

3. be full of guts
[美國俚語]膽量極大；精力充沛；（小說、圖畫等）很有精神；[美國俚語]厚顏無恥