1. Do you have a technical English terms for 'animals' teeth?

2. The squirrel is a little heavy.
3. The rabbit is somewhat small.
4. The puppy is rather medium.
5. The parrot is kind of small.

(Are the expressions all grammatical? Do you have more expressions similar to 'a little'?)

1. Sometimes certain teeth are referred to as fangs.

http://upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Fangs_01_rfc1036.jpg/220px-Fangs_01_rfc1036.jpg

The long, pointy ones are referred to as fangs; the rest are teeth. Molars are the large-surfaced teeth in the back of the mouth that are used to chew food.
All kinds of cats, all kinds of dogs and wolves, snakes ... these are examples of animals that have fangs.

2 - 5 -- all are fine.