What don't have hair and reproduce young alive?

Animals that don't have hair and reproduce young alive include certain species of reptiles, such as snakes and lizards, as well as some fish, like livebearers (e.g., guppies and mollies). These creatures typically have scales instead of hair and give birth to live young rather than laying eggs. This mode of reproduction allows their offspring to be more developed when they are born, increasing their chances of survival in the wild.