What animals other than humans exploit other animals?

Ants farm aphids. There are also examples of ants enslaving other species of ants (known as cuckoo ants) Also on that note, cuckoos exploit other species for raising their offspring. Many bird species do this, cow-birds, honey-guides, cuckoos, some ducks.... also cuckoo catfish... bumblebees and wasps have examples of this too... among others.