It’s one of the ocean’s great paradoxes: some of the largest animals to ever live survive almost entirely on some of the smallest. Baleen whales — the group that includes blue whales, gray whales, and humpbacks — don’t have a single tooth. Instead, they’ve evolved one of the most efficient feeding systems in nature. Here’s exactly what’s on the menu, and how they manage to eat enough to fuel a body the size of a school bus.
What’s on the Menu for a Baleen Whale?
Baleen whales feed low on the food chain, targeting krill, copepods, and other zooplankton, along with small schooling fish like anchovies and herring. What they eat depends on the species: blue whales feed almost exclusively on krill, right whales favor copepods, humpbacks eat a mix of krill and small fish, and gray whales — the species most commonly seen off our coast — dig into the seafloor for tiny amphipods. You can read more about these differences across whale species in what whales eat.
How Filter Feeding Actually Works
In place of teeth, baleen whales have rows of comb-like plates made of keratin — the same material as human fingernails — hanging from their upper jaw. To feed, a whale opens its mouth wide and takes in a huge volume of water along with whatever prey happens to be swimming through it. It then partially closes its mouth and pushes the water back out through the baleen with its tongue, while the bristly plates trap the krill, plankton, or small fish inside. Some species, like right whales, “skim feed” by swimming slowly with their mouths open near the surface, while others, like humpbacks, lunge dramatically into dense schools of prey.
How Much Do Baleen Whales Eat?
The numbers are staggering. During peak feeding season, a blue whale can eat up to 8,000 pounds of krill in a single day, swallowing roughly 24 pounds of krill in a single gulp. That kind of intake is what allows these animals to build and maintain the enormous size we cover in how big whales really get — and to store enough energy to survive long migrations when they’re not feeding at all.
Baleen vs. Toothed Whales: A Quick Comparison
Not all whales filter feed. Toothed whales — orcas, dolphins, sperm whales — hunt individual prey one at a time using teeth and echolocation. Baleen whales take the opposite approach: instead of chasing down a single fish, they engulf entire schools or swarms at once. Both strategies work incredibly well; they’ve just evolved to solve the “how do I eat enough to survive” problem in very different ways.
Watching Baleen Whales Feed in Southern California
Guests on our tours often get to see filter feeding firsthand, especially during gray whale migration season and when humpbacks pass through chasing bait fish. Watching a whale lunge through a school of anchovies or skim the surface for krill is one of the most memorable parts of a trip. Learn more about what to expect on a Harbor Breeze whale watching tour throughout the year.
See Filter Feeding in Action
The best way to understand how a baleen whale eats is to watch one do it. Book a Long Beach whale watching tour with Harbor Breeze Cruises and see one of nature’s most efficient feeding machines up close.