Does every turtle bite

Answer 1

While most certainly have the ability to bite, it's only a hazard with larger species such as Alligator Snapping Turtles. They will not bite maliciously, most will only bite if they feel threatened (even then, they are more likely to pull into their shell than to bite!).

(Even species that mostly eat plants can bite - my desert tortoises will occasionally think that fingers/toes are worth trying to eat. Like all pets, you just have to watch where the animal's mouth is in relation to your body parts!)