Whales are marine mammals belonging to the order Cetacea, and their global habitat spans all the world’s oceans. Determining where the largest number of these creatures lives is complicated because their distribution is not static. The location of any given whale population changes dramatically based on the species, feeding requirements, and the time of year. This continuous movement means that the concentration of whales shifts seasonally between productive feeding areas and sheltered breeding grounds.
Environmental Drivers of Whale Distribution
The primary factors dictating where whales concentrate are food availability and water temperature. Whales, particularly larger species, require immense amounts of energy, which ties their distribution directly to areas of high marine productivity. This necessity explains why the coldest regions of the world’s oceans support the highest biomass of whales.
Cold, nutrient-rich waters in the polar and sub-polar zones are characterized by processes like upwelling. Upwelling brings deep, nutrient-dense water to the surface, fueling massive blooms of phytoplankton and zooplankton. This abundance creates a dense food source, such as krill, which is the foundational diet for many of the world’s largest whales.
For example, the Southern Ocean surrounding Antarctica, and high-latitude areas in the North Pacific and North Atlantic, become temporary feeding grounds where whales aggregate in the summer. These areas, rich in chlorophyll-a, allow species to build up the blubber reserves needed for the rest of the year. The cooler temperatures of these waters also support complex food webs by holding more dissolved gases and nutrients.
Conversely, warmer waters near the equator are less productive due to a lack of upwelling. These tropical and subtropical zones are often avoided for feeding but are favored for other biological needs. This preference for food-rich cold water over nutrient-poor warm water is a fundamental driver of their global distribution patterns.
Contrasting Habitats of Baleen and Toothed Whales
The two major suborders of Cetaceans, baleen whales (Mysticetes) and toothed whales (Odontocetes), exhibit distinct habitat preferences due to their different feeding mechanisms. Baleen whales, including species like humpbacks and blue whales, are filter feeders that rely on concentrations of small prey. Their specialized diet of krill, plankton, and small schooling fish forces them to seek out the most productive, high-latitude waters in the summer.
Baleen whales have a predictable and geographically restricted habitat preference focused on productive polar and sub-polar regions during their feeding season. Their size and energy demands necessitate the consumption of dense, easily captured prey aggregations. This reliance on seasonal productivity means their range is defined by the world’s cold-water upwelling zones.
Toothed whales (Odontocetes), a diverse group including sperm whales, orcas, and dolphins, have a broader global distribution. Their active hunting style, using conical or spade-shaped teeth to catch individual prey, allows them to exploit a wider variety of habitats and prey, such as fish and squid. The sperm whale, for instance, dives thousands of feet into the deep ocean to hunt giant squid, preferring deep-water habitats inaccessible to most baleen whales.
Many smaller toothed whales, such as dolphins and porpoises, prefer temperate and tropical coastal waters, further widening the group’s range. While toothed whales are numerically more numerous, their populations are often more widely dispersed across the globe. This contrasts with the concentrated, seasonally transient populations of baleen whales in cold-water feeding zones.
Seasonal Movement and High-Density Hotspots
The answer to where most whales live is complicated because many of the largest species are constantly in motion, following a pole-to-equator migration pattern. This movement is a biological necessity, allowing them to capitalize on seasonal food surpluses in cold waters while using warm waters for reproduction. They migrate thousands of miles from summer feeding grounds to winter breeding grounds, often traveling without feeding for months.
During the winter, many baleen whales aggregate in shallow, warm tropical and subtropical waters to give birth and mate. These warmer waters offer a safer environment for calves, which lack the blubber reserves needed to survive in polar zones. The lack of feeding in these areas means the high whale concentration is temporary and tied to the breeding season.
These seasonal aggregations create temporary high-density hotspots where the number of whales is at its peak. For instance, the Gulf of Alaska becomes a major feeding hotspot for humpback whales and other large rorquals during the northern summer. Conversely, in the winter, coastal lagoons off Baja California, Mexico, become calving havens for the Pacific gray whale population. The waters off the southeastern United States coast are also a winter calving area for the North Atlantic right whale, which feeds off New England and Canada in the summer.