According to the Dream Dictionary at dreammoods.com, pets can symbolize things such as:
Dog: "To see a happily barking dog in your dream, symbolizes pleasures and much social activity. If the dog is barking ferociously, then it represents your habit of unnecessary barking at people and the situations around you. It could also mean unfriendly companions."
Cat: "If a cat is biting you, then it symbolizes the devouring female. Perhaps you are taking and taking without giving. You may be expressing some fear or frustration especially when something is not going as planned. If you see a cat with no tail, then it signifies a loss of independence and lack of autonomy."
Lizard: "To see a lizard in your dream, signifies your primal instincts and reactions toward sex, food, etc. and your anxieties toward these feelings."
Hamster: "To see a hamster in your dream, represents underdeveloped emotions."
Who's been in your dreams lately? Maybe you should see what's up with that.