Whales, as some of the most enormous creatures on our planet, are fascinating marine mammals belonging to the cetacean family, which encompasses around 90 distinct species, including dolphins and porpoises. These magnificent beings are categorized into two primary groups: baleen whales and toothed whales, based on the presence of teeth or baleen plates in their mouths.
A whale’s diet plays a crucial role in their massive body weight and blubber storage, affecting not only their survival but also the broader marine ecosystem they inhabit. Each species of whales displays unique feeding habits, varying across the diverse cetacean groups and odontocetes. Get ready to explore the intriguing world of whale diets and their impact on the marine ecosystem, from the Southern Ocean’s sediment layers to the requirements of food intake during feeding seasons.
What Do Whales Eat? It Depends on the Type!
Whales are enormous creatures with correspondingly large appetites, consuming various marine life to sustain their energy for mating and reproducing. The diet of a whale relies heavily on its type, which can be broadly categorized into two primary groups: baleen whales and toothed whales.
Baleen whales delight in feasting on vast quantities of smaller marine creatures such as krill, shrimp, phytoplankton, algae, and zooplankton. On the other hand, toothed whales are more inclined to actively hunt for larger prey like squid, octopuses, sharks, and even marine mammals.
So, depending on the species, like the blue whale, humpback whale, or sperm whale, a whale’s diet can vary considerably, including everything from the tiniest oceanic organisms to larger marine animals like orcas, dolphins, fin whales, gray whales, and sei whales.
How Baleen Whales Eat
Various Techniques of Filter Feeding
Baleen whales, which include 16 distinctive species such as the blue whale and the humpback whale, possess a unique feeding anatomy. They use baleen plates in their mouths to filter food from the water in a process called filter feeding. These baleen plates are made of keratin, the same material found in human hair, skin, and nails. They are lined with thousands of baleen hairs or whalebone hairs, which are strong and flexible.
After straining water into their mouths, baleen whales are able to trap small crustaceans, plankton, and tiny fish within the baleen hairs. The whales then use their tongues to lick the trapped food off the baleen and swallow it. There are three main filter feeding methods utilized by these baleen whales: lunge feeding, skim feeding, and bottom feeding.
Lunge Feeders: Blue and humpback whales, among the most common types of baleen whales, use this feeding method. They swim rapidly through the water to gather momentum before lunging at a school of fish with their mouths open. As they gulp down water and fish, the whales employ their tongues and throats to push the water out through the small gaps between the baleen hairs. The remaining fish, trapped between the baleen hairs and within their mouths, are then swallowed.
Skim Feeders: Bowhead whales, for example, swim slowly toward their prey, pulling in fish and water through a gap in their baleen plates. They function similarly to lunge feeders but at a slower pace. Skim feeders usually prefer skimming the ocean’s surface, although they can filter feed at any depth, including the ocean floor.
Bottom Feeders: Gray whales, in particular, are known for this feeding technique, where they swim close to the ocean floor, drawing in water and tiny prey through their baleen plates. Like skim feeders, they filter out the water to consume the remaining crustaceans and fish. This method results in long trails of mud on the ocean floor left by the gray whales’ bodies as they glide along the surface.
What Do Baleen Whales Eat?
Baleen whales have a similar diet due to the narrow spaces between their baleen hairs, allowing them to consume large amounts of small prey. Their diet primarily consists of:
- Krill
- Shrimp
- Copepod crustaceans such as water fleas
- Small fish like anchovies and herring
- Zooplankton
- Phytoplankton
- Algae
These whales filter and consume various types of plankton and small marine organisms to sustain themselves.
How Do Toothed Whales Eat?
Toothed whales, such as killer whales and sperm whales, belong to a group called Odontocetes, which consists of 73 different species. These whales are generally smaller and more agile compared to most baleen whales. Their characteristic sharp, cone-shaped teeth allow them to efficiently capture and tear apart prey.
When feeding, toothed whales straightforwardly stalk their prey, lunge when near, and pull the prey into their mouths. Usually, prey includes fish or squid, which they may even swallow whole.
An interesting observation from a 2017 study was the correlation between a toothed whale’s skull size and the prey size it consumes. Utilizing 3D imaging, researchers found a strong link between the sizes of various toothed whales’ craniums and the prey they eat. In essence, whales with larger skulls tend to consume larger prey, while those with smaller or more elongated, narrow skulls prefer smaller animals.
These whales also use echolocation to locate prey and navigate underwater. They emit sound waves that bounce off objects, enabling them to locate and identify their targets. With their highly adapted teeth, pods for social hunting, and echolocation skills, toothed whales make up an incredible group of marine predators.
What Toothed Whales Consume
Toothed whales have a diverse diet, as they are versatile hunters well-adapted to capturing larger prey compared to their baleen relatives. Toothed whales commonly feed on a variety of marine animals, including:
- Squid: A popular choice among toothed whales, squid offers a nutritious meal.
- Octopus: Another cephalopod, the octopus is occasionally on the menu for these whales.
- Crustaceans: From small shrimp and krill to larger crabs and lobsters, toothed whales enjoy crustaceans of all sizes.
- Fish: Depending on their location, toothed whales eat various fish species such as halibut, herring, smelt, and mackerel.
- Seals: Some toothed whales, like the infamous killer whale, have been known to hunt seals.
- Sea birds: Opportunistic hunters, toothed whales may occasionally snatch a seabird from the water surface.
- Sharks and rays: Another example of their diverse diet, toothed whales are even known to consume sharks and rays.
- Walruses: Although uncommon, toothed whales may occasionally hunt down a walrus.
Moreover, some toothed whales, particularly killer whales, are known to prey on other whales, dolphins, and porpoises. This diverse diet demonstrates the adaptability and hunting prowess of toothed whales in their marine environment.