If these great cats become extinct, the smaller animals they prey upon will overpopulate the forests.

如果这些大型猫科动物灭绝了，那么它们捕食的小型动物将会使森林中物种的密度过高。

Stronger animals prey upon weaker ones.

强大的动物捕食弱小的动物。

The Internet can be full of dark, scary people who prey upon people's naivety and innocence.

互联网上可能充斥着各种阴森恐怖的人，他们专门利用人们的天真无邪。

It seemed to me also that every living African, whether in good or ill health, is prey to many enemies of health that would interact one upon the other in many ways within one human body, Critics feared if President Mbeki appeared to doubt the link between HIV and the disease, people would not practice safe sex and use condoms.

VOA : standard.2010.05.17

Let that be understood by those who practice terrorism and prey upon their neighbors.

CNN: Inaugural Address

Almost all of these guys are retail brokers dressed up and sent out into the world to prey upon pensions.

FORBES: The Art of Theft: How Corporate Fiduciaries Steal From American��s Pensions (February 2, 2005 )

Desperate people are willing to do almost anything when catastrophe strikes and these scamsters prey upon them like buzzards.

FORBES: Hurricane Sandy Will Flood Northeast with Disaster Scams: How to Avoid Them