Like all other "boss" dinos, the triceratops should be a high priority target, killing it before raptors is highly recommended.
The triceratops has a charge attack and a stomp attack, both of which can be devastating if they hit a carrier.
The stomp attack has an area of effect. It deals moderate damage and sends players flying into the air. You can evade this attack by jumping into the air before her feet hit the ground.
The charge sends the triceratops running forward and hitting players in its path. The impact deals moderate damage and hits you backwards. Get out of harms way with a quick roll to the side.
If you're standing in front of her, she'll also bite you.
With the Arctic Update (coming in November 2013), the Triceratops will become the fourth playable dinosaur in Dino Horde. The developers made a poll on the Steam forums and let users vote for the dinosaur they'd like to play. Dolly won easily.