What Do Whales Eat?

Few questions about ocean life are as surprising to answer as this one. You’d expect the largest animals on Earth to be fearsome predators — but the biggest whales alive today survive almost entirely on creatures you could hold in your hand. Meanwhile, some of the smaller whale species are among the most sophisticated and ruthless hunters in the ocean. What whales eat depends almost entirely on the species, and the range is extraordinary.

Here’s a complete breakdown of whale diets — how different species find their food, what they eat, and just how much of it they consume.

The Two Types of Whales — and Why It Determines Everything

All whales fall into one of two categories, and that division is the single biggest factor in determining what they eat and how they hunt.

Baleen whales — including blue whales, humpbacks, gray whales, fin whales, and minke whales — have no teeth. Instead, they have baleen plates hanging from their upper jaw: rows of stiff, bristled keratin that function like a giant sieve. These whales feed by taking in enormous volumes of water and prey, then pushing the water out through their baleen while trapping food inside. They eat small — krill, small fish, copepods, plankton — but in staggering quantities.

Toothed whales — including sperm whales, orcas, and beaked whales — have teeth and are active hunters. They use echolocation to locate prey, chasing and catching individual animals. Their diets range from fish and squid to seals, sharks, and in some cases, other whales.

What Do Blue Whales Eat?

Blue whales eat almost exclusively krill — tiny shrimp-like crustaceans that measure barely an inch or two in length. The irony of the largest animal on Earth surviving on one of the smallest is not lost on anyone who has thought about it for more than a few seconds.

Research indicates that in a single day of peak feeding, a blue whale can eat approximately 16 tonnes of krill — the equivalent of roughly 8,800 quarter-pound burgers. A blue whale ingests approximately 83% of the calories it needs for the entire year in just 90 to 120 days of active feeding in cold, nutrient-rich waters during summer months. 

Blue whales feed by lunging into dense swarms of krill with their mouths open, engulfing both prey and water. A single blue whale has around 300 to 400 baleen plates on each side of its upper jaw, which trap the krill as the whale’s massive tongue forces the water back out. 

Krill tend to migrate toward the surface at night and dive deeper during the day, which means blue whales do much of their feeding at around 300 feet below the surface during daylight hours, following the vertical movement of their prey throughout the day. 

Daily consumption: Up to 16 tonnes (approximately 35,000 lbs) at peak feeding

What Do Humpback Whales Eat?

Humpbacks eat krill and small schooling fish — herring, mackerel, capelin, and sand lance among them. An average-sized humpback whale will eat between 4,400 and 5,500 pounds of plankton, krill, and small schooling fish each day during the feeding season, which lasts approximately 120 days in cold waters. During the winter months on their breeding grounds in places like Hawaii and Mexico, humpbacks eat little to nothing, surviving on the blubber reserves built up during the summer feeding season.

What makes humpbacks truly remarkable isn’t what they eat — it’s how they eat it.

Bubble Net Feeding: The Most Sophisticated Hunting Technique in the Ocean

Bubble net feeding is a cooperative hunting method used by groups of humpback whales. It is not instinctual — it is learned, and not every population of humpbacks knows how to do it. 

The hunting members of a pod form a circle between 10 and 100 feet across at about 50 feet underwater. They then blow a wall of bubbles as they swim upward in a spiral path. The cylindrical wall of bubbles traps krill, plankton, and small fish, concentrating them into a dense mass near the surface. At a coordinated signal, the humpbacks lunge upward through the center of the bubble column with their mouths open. 

As the whales surface to feed, they can hold up to 15,000 gallons of seawater in their expandable mouths. The 14 to 35 throat grooves running from chin to navel allow the mouth to balloon outward before the whale strains the water back out through its baleen and swallows the trapped fish. 

It’s one of the most coordinated and visually dramatic feeding behaviors in the animal kingdom — and you can witness it firsthand on a Harbor Breeze tour when humpbacks are feeding in the waters off Southern California.

Daily consumption: 4,400–5,500 lbs during feeding season

What Do Gray Whales Eat?

Gray whales are unique among baleen whales in that they are primarily bottom feeders. Rather than lunging for prey in the water column, gray whales dive to the seafloor, roll onto their sides, and use their short, coarse baleen to sieve amphipods, ghost shrimp, small crabs, tube worms, and other bottom-dwelling creatures from the sediment.

Gray whales eat approximately 340,000 lbs of food during a 130 to 140 day feeding period — a daily average of about 2,400 lbs. They gain between 16% and 30% of their total body weight during the feeding season, storing energy as blubber that sustains them during their extraordinary migration and breeding season when they eat little or nothing. 

The gray whales you’ll see on Harbor Breeze tours during December through April are on this very migration — traveling between their summer feeding grounds in Alaska and their winter breeding lagoons in Baja California, passing through the waters off Long Beach and San Pedro along the way.

Daily consumption: ~2,400 lbs during feeding season

What Do Fin Whales Eat?

Fin whales — the second-largest animals on Earth — are lunge feeders like blue whales, but their diet is slightly more varied. Fin whales eat krill, copepods, squid, and a variety of small schooling fish. They are among the fastest of all large whales, capable of bursts up to 23 mph, which supports their lunge-feeding strategy of accelerating rapidly into prey patches.

Fin whales are regularly spotted in the waters off Southern California during summer and fall, often alongside blue whales and humpbacks in productive feeding areas.

What Do Sperm Whales Eat?

Sperm whales are the largest toothed whales on Earth, and their diet reflects their hunting prowess. They are deep divers — regularly descending to depths of 1,000 meters or more — in pursuit of their primary prey: giant and colossal squid.

It is believed that sperm whales consume an astonishing amount of squid annually. The circular suction marks from squid and octopus are often visible around the heads and mouths of sperm whales — evidence of prey that fought back during the hunt in the deep, lightless water column. 

Sperm whales also eat large fish, including deep-sea species, and their teeth — which only erupt on the lower jaw — are used to grip prey rather than chew it. Like all whales, they swallow their food whole.

What Do Orcas (Killer Whales) Eat?

Orcas are the most dietary diverse of all whale species. Studies have documented that orcas prey on over 140 animal species worldwide. But here’s the key detail that most people don’t know: what an individual orca eats depends almost entirely on which population it belongs to.

In the eastern North Pacific, resident killer whales are highly specialized fish eaters — salmon makes up 96% of their diet, with Chinook salmon being the preferred species. There is no evidence of resident killer whales eating marine mammals. Transient killer whales in the same region, however, specialize in marine mammals — seals, sea lions, dolphins, and other whale species — and the two populations do not interbreed or socialize. 

Orcas have been observed targeting calves of species like blue whales and humpback whales — isolating calves from their mothers using coordinated pod tactics. They have also been documented hunting great white sharks, targeting the nutrient-rich liver specifically.

An average-sized orca eats approximately 551 lbs of food per day. Hunting techniques vary by population and prey — carousel feeding for fish, wave-washing for seals on ice floes, and cooperative multi-whale attacks for large prey.

Daily consumption: ~551 lbs

Whale Feeding: Quick Reference by Species

Why Whale Feeding Matters for the Ocean

When whaling decimated whale populations during the 20th century, it didn’t just reduce whale numbers — it disrupted the entire ocean ecosystem. Whales recycle nutrients through their fecal plumes, spreading iron and other vital elements near the ocean surface. This iron fertilizes phytoplankton growth, which supports krill populations, which feed the whales. Without whales, this cycle broke down. Today, krill populations in the Southern Ocean are down by over 80% since the end of whaling — not because of overfishing, but because the nutrient recycling system that sustained them was removed.

In short, what whales eat — and how much of it — isn’t just a fascinating biological fact. It’s one of the core mechanisms keeping the ocean’s food web functioning.

See Feeding Whales Off Southern California

Harbor Breeze Cruises runs year-round whale watching tours from Long Beach and San Pedro, where humpbacks, blue whales, gray whales, and fin whales all feed and migrate through the waters offshore. Check our live whale sightings page to see what’s been spotted recently, and book your tour today.