Here's why:
* Manatees are large herbivores: They primarily eat plants, grasses, and other aquatic vegetation.
* Oceanic predators: The main predators of manatees are large animals like crocodiles, sharks, and some large fish. These predators are carnivores, not omnivores.
Omnivores are animals that eat both plants and animals. While there are omnivores in the ocean (like some types of fish), they generally don't target animals as large as manatees.