Perhaps you're thinking of a specific animal that starts with "bio"? If you can give me more context, I can help you figure out what animal you're thinking of.
What type of animal is an bio?
"Bio" isn't an animal. It's a prefix that means "life" or "living." It's often used in scientific terms like "biology" (the study of life) or "biodiversity" (the variety of life in a particular habitat).