What is a whale?

Whales are part of the incredibly diverse group of marine mammals known as cetaceans. These highly adapted animals are among the most specialized creatures living in the oceans today.

Cetaceans vary greatly in size, ranging from tiny porpoises measuring just over one metre long to the enormous blue whale, the largest animal on Earth. Blue whales can reach lengths of around 24 metres and weigh as much as 84 tonnes.

Over millions of years, whales have developed remarkable adaptations that allow them to thrive in marine environments. Their bodies are so specialized for ocean life that their origins were once difficult to understand. Fossil discoveries have revealed that whales evolved from small land-dwelling mammals that began entering aquatic environments more than 50 million years ago.

The word “whale” is often used to describe the larger members of the cetacean family, including the biggest toothed whale, the sperm whale made famous by Moby Dick, as well as the great baleen whales that were heavily hunted in the past.

Two Main Groups of Cetaceans

Cetaceans are separated into two major categories: toothed whales and baleen whales.

Toothed whales have teeth and use them to capture larger prey such as fish and squid. Baleen whales do not have teeth; instead, they possess specialized filtering structures called baleen plates that allow them to collect tiny organisms from seawater.

Toothed Whales

Four species of toothed whales live in Antarctic waters: the sperm whale, southern bottlenose whale, orca (killer whale), and southern four-tooth whale.

With the exception of the sperm whale, these species are generally smaller than baleen whales and were not targeted by large-scale hunting operations. Their teeth allow them to catch larger prey, including fish and squid.

Orcas are especially skilled hunters and often work together in groups to capture animals such as penguins and seals.

Baleen Whales

Six species of baleen whales are found around Antarctica: the blue whale, fin whale, southern right whale, sei whale, minke whale, and humpback whale.

The term “baleen” refers to the large, comb-like plates found inside their mouths. These structures act like filters, allowing whales to strain tiny food sources such as krill, plankton, and small crustaceans from the ocean water.

Whale Migration Patterns

Many whales that live in the Southern Ocean undertake long migrations. During the Antarctic winter, they travel toward warmer tropical waters where they give birth to their calves.

Young whales are unable to survive the extremely cold conditions of Antarctic waters, so warmer regions provide a safer environment for newborns. When spring arrives in the Southern Hemisphere, whales return south by following the retreating ice edge, where rich feeding areas develop due to high biological activity.

Young calves often remain with their mothers during these yearly migrations for several years. Female whales usually do not reproduce again until their offspring have become independent.

From Whale Hunting to Conservation

For centuries, whales were heavily exploited because of the valuable oils and materials they provided. The demand for whale products drove extensive ocean exploration and commercial hunting around the world.

During the 20th century alone, more than 1.3 million whales were killed in Antarctic waters. Before widespread hunting, scientists estimate that there may have been more than 225,000 blue whales. Today, fewer than 2,000 are believed to remain.

The decline of whale populations helped inspire the modern conservation movement. People began recognizing the importance of whales in maintaining healthy ocean ecosystems and understanding the need to protect these extraordinary animals.

Today, whales are no longer viewed only as resources. Millions of people now experience the wonder of seeing whales in their natural habitats through whale-watching activities, creating a new and more sustainable connection between humans and these magnificent marine mammals.