Zebra, the humanitarian (or "zebratarian"). Focused almost solely on devising ways to protect his fellow zebras on the plains from their numerous, more able predators.
Rat is arrogant, self-centered, fatalistic and quick-tempered. Rat is obsessed with fame, immortality and making a quick buck.
Pig is humble (if not painfully aware of his limitations), practical, kind and a little slow in the head. Pig has few aspirations other than to spend his days watching TV and doing nothing productive.
Goat is the smart one. He would rather spend his time with his snout in a book than talking to any other characters in the strip, but he's often the reluctant mentor.