You got to look out for number one.

人不为己 天诛地灭。

I'm looking out for number one.

我正在寻找第一名。

So his advice for other archaeologists who want to track animal and human populations? Look out for number one.

那他对其他想追踪动物和人类种群的考古学家有何建议？留意尿液。

You could be looking out for number one for yourself and your own interests.

您可能会为自己和自己的利益寻找第一。