BWB – Different marine mammals

Marine mammals are a fascinating and diverse group of animals that differ in their lifestyles, anatomical features and ecological roles. The best-known groups include whales, seals, manatees and dolphins.

Whales belong to the order Cetacea and include baleen whales and toothed whales. Baleen whales filter plankton and small fish from the water. Toothed whales are predators that hunt fish and squid.

Dolphins are also categorised as toothed whales, but belong to the Delfinidae family. They are characterised by their high intelligence, social interactions and complex communication methods. Dolphins live in groups. They often hunt in a coordinated manner. Their slender bodies and distinctive dorsal fins allow them to move quickly and manoeuvrable in the water.

Seals, on the other hand, belong to the order Pinnipedia, which also includes sea lions and walruses. Compared to whales and dolphins, seals are amphibious – they live both in the water and on land. Their streamlined bodies and powerful flippers are ideal for swimming, while on land they make progress by sliding or short movements on their flippers. They mostly feed on fish and crustaceans.

Manatees include manatees and dugongs. These animals are herbivores that live in warm coastal waters and estuaries. They have rounded bodies, paddle-like front flippers and no dorsal fin. Manatees are slow and spend most of their time grazing on seagrass beds or aquatic plants.

While whales and dolphins move by vertical tail slaps, seals and manatees use flippers or paddle-like limbs. Seals use their hind flippers in the water and their front flippers on land.

All marine mammals breathe air through lungs, which distinguishes them from fish. Whales and dolphins have blowholes on their heads, while seals and manatees can close their nostrils to allow long dives.

The diet varies greatly: whales and dolphins are mostly carnivores, seals feed on a mixture of fish and molluscs, while manatees are pure herbivores.

Dolphins and toothed whales are known for their complex social structures and acoustic communication. Seals communicate primarily through sounds and visual signals, while manatees tend to live in seclusion and only make a few sounds.

By Fatima Kutzschbach