* Dolphins are marine mammals, meaning they live in the ocean and breathe air. They can be found in various zones, but are most common in the pelagic zone (open ocean).
* Sea turtles are reptiles that live in the ocean. They are also found in different zones, including the pelagic zone, but they also spend time in the neritic zone (near the coast) and even come ashore to lay eggs.
* Starfish are invertebrates that live on the benthic zone, the ocean floor.
* Horses are land mammals. They do not live in the ocean.
Therefore, while some of these animals may share some overlapping habitats, they do not live in the *same* ocean zone.