Penguins rely on their black and white coloration for camouflage. In the water, their black backs blend in with the dark depths, making them difficult for predators to spot from above. Their white bellies, on the other hand, help them blend in with the bright surface of the water when viewed from below. This countershading makes them less visible to predators such as seals and killer whales.
Additionally, penguins have a streamlined shape that helps them move quickly and efficiently through the water. This can also help them avoid predators.