Whales are diverse marine mammals known for their immense size and varied diets. Their methods of obtaining food are highly specialized, reflecting adaptations to different ocean environments and prey types. These feeding strategies are fundamental to their survival and play a significant role in marine ecosystems.
The Two Main Feeding Strategies
Whales are broadly categorized into two suborders based on their feeding apparatus: baleen whales (Mysticeti) and toothed whales (Odontoceti). Baleen whales are filter feeders, designed to strain small organisms from large volumes of water. Conversely, toothed whales are active hunters, pursuing and catching individual prey items.
Filter Feeding Giants: Baleen Whales
Baleen whales, lacking teeth, possess rows of baleen plates in their upper jaws, which act like a sieve. These plates are made of keratin, the same protein found in human hair and nails, and feature fine, bristly fringes that interlock to form a dense mat. Water and food enter the mouth, and as the whale pushes the water out with its tongue, the baleen traps the prey inside. This filtering mechanism allows them to consume vast quantities of small organisms such as krill, copepods, and small schooling fish.
Lunge Feeding
Lunge feeding is a method used by species like blue whales and fin whales, where they rapidly engulf large volumes of water and prey. Their expandable throat pleats allow their mouths to balloon outwards, holding tons of water and food, which is then filtered through the baleen. Blue whales, the largest animals on Earth, can consume up to 8,000 pounds of krill daily during peak feeding.
Skim Feeding
Skim feeding is a strategy observed in right whales, where they swim with their mouths open through dense patches of prey, continuously filtering food as water flows through their baleen plates. The bowhead whale, with baleen plates up to four meters long, often uses this method, swimming along the surface with its mouth open.
Bubble-Net Feeding
Humpback whales are known for their cooperative bubble-net feeding, where groups of whales work together to blow bubbles in a circular pattern around schools of fish or krill. This creates a “net” of bubbles that disorients and corrals prey, allowing the whales to lunge upward through the concentrated food.
Active Hunters: Toothed Whales
Toothed whales, including dolphins, porpoises, and sperm whales, possess conical teeth primarily for grasping and tearing prey, rather than chewing. Their diet is diverse, consisting of fish, squid, and in some cases, other marine mammals. These active predators employ hunting strategies to locate and capture their prey.
Echolocation
Echolocation, or biosonar, is a primary tool for toothed whales, especially in dark or murky waters. They produce high-frequency clicks and sounds that travel through the water, bounce off objects, and return as echoes. These echoes are received by fatty tissues in their lower jaw and transmitted to the inner ear, allowing the whale to create a detailed “acoustic image” of its surroundings, determining the size, shape, distance, and movement of prey. Sperm whales, for instance, use powerful, lower-frequency clicks to locate giant squid in deep ocean environments. Some toothed whales can even generate sounds powerful enough to stun their prey, making it easier to capture.
Cooperative Hunting
Cooperative hunting is a notable strategy among some toothed whales, such as orcas and dolphins. These animals work together to herd or ambush prey. Orcas are known for their coordinated efforts, sometimes forming “bubble nets” similar to those of humpbacks, or creating waves to wash seals off ice floes. This teamwork allows them to target larger or more elusive prey species that would be difficult to catch individually.