For videos, VLC (AKA "Video Lan Client") is your friend. Plays practically any video format in use today, and there's a version available for all major operating systems, including iOS.
Although personally, the day I use an iOS device - or any other linked-to-a-cell-phone-account device - to access zoo/beasty sites will be the day they know it's time to wheel me into the Alzheimer's ward 'cause I've lost the last vestiges of sensible caution - If you're set on getting busted, wouldn't it be less effort to just paint up a nice 10 foot square sign that reads "I fuck animals" and march up and down in front of the local animal shelter or police station?