--- title: "Blue Whales Eating Krill: How Lunge Feeding Works" url: https://thesea.org/blue-whales-eating-krill/ date: 2026-11-13 modified: 2026-11-13 lang: en author: "Blane Perun" description: "TheSea.Org▸Bioluminescence & Plankton▸Krill▸Blue Whales Eating Krill Blue Whales Eating Krill — Lunge Feeding by the Numbers Bioluminescence & Plankton By Blane Perun November 13, 2026 10 min read How do..." categories: - "Coral Reef" word_count: 2004 --- # Blue Whales Eating Krill: How Lunge Feeding Works [TheSea.Org](/)▸[Bioluminescence & Plankton](/bioluminescence/)▸[Krill](/krill/)▸Blue Whales Eating Krill # Blue Whales Eating Krill — Lunge Feeding by the Numbers Bioluminescence & Plankton By [Blane Perun](/about-blane-perun/) November 13, 2026 10 min read How do blue whales eat krill? Blue whales eat krill by **lunge feeding**. A whale accelerates into a dense krill swarm, opens its jaws almost 90 degrees and expands its **pleated throat** to engulf a mouthful of water that can be as large as its own body. It then pushes the water out through **baleen plates**, trapping the krill. In peak season a blue whale may eat on the order of **several to 16 tonnes of krill a day**. Quick facts Main foodKrill, almost exclusively Feeding methodLunge feeding (engulfment) MouthfulUp to roughly its own body volume of water Daily intake (peak season)Estimates from ~4 t to ~16 t FilterSeveral hundred baleen plates per side Typical feeding depthOften 100–300 m by day Lunges per diveSeveral Krill sizeAbout 1–6 cm The largest animal that has ever lived feeds almost entirely on one of the smallest animals you can see with your naked eye. A blue whale can be close to 30 metres long and weigh well over 100 tonnes, and it gets nearly all of that bulk from krill, shrimp-like crustaceans a few centimetres long. It sounds impossible until you look at how a blue whale eats: not one krill at a time, but entire swarms in a single gulp. This page explains lunge feeding step by step, how much krill a blue whale really eats, where it finds enough of them, and why the whole system is more fragile than its scale suggests. For the krill side of the story, see our [krill](/krill/) page, and for the whale itself, our [blue whale](/blue-whale/) guide. Why krill, of all things? Krill are small, but they are rich, abundant and, crucially, they swarm. A blue whale is not eating individual animals; it is harvesting patches. Krill are high in fat and protein, and in the right places and seasons they gather in swarms so dense that there can be thousands of animals in a single cubic metre of water. A whale that finds one of those patches can take in an enormous amount of food in seconds. Feeding on a food at the bottom of the food chain is also efficient: energy is lost at every step up a food web, so cutting out the middle steps (fish that eat krill, say) gives the whale access to far more energy than eating fish would. The same logic explains why the other giants of the ocean, the whale shark, basking shark and manta rays, are filter feeders too. Our [ocean food web](/oceans-food-web/) guide explains why short food chains support big animals. Blue whales are specialists. Other baleen whales, such as humpbacks and fin whales, eat krill but also small schooling fish. Blue whales feed almost entirely on krill, including *Euphausia superba* in the Antarctic and species such as *Thysanoessa spinifera* and *Euphausia pacifica* off California. ![Blue whale lunge feeding on its side with throat pouch swollen, blue whales eating krill](https://thesea.org/wp-content/uploads/blue-whales-eating-krill-1-thesea-org-by-blane-perun.webp)Blue whale lunge feeding on its side with throat pouch swollen, blue whales eating krill Lunge feeding, step by step Lunge feeding is one of the most extreme feeding behaviours in the animal kingdom. Using suction-cup tags fitted with depth sensors, accelerometers and cameras, researchers such as Jeremy Goldbogen and colleagues have been able to reconstruct each lunge in detail. First, the whale finds a patch, often on a dive to 100 metres or deeper during the day, when krill sink to avoid predators. It then accelerates with a few strong tail beats toward the swarm. Close to the krill, it drops its lower jaw until its mouth is open almost at a right angle. Water rushes in, and the pleated throat, a series of long grooves running from the chin to the belly, balloons outward like a parachute. This throat pouch can hold a volume of water and krill roughly equal to, or even larger than, the whale’s own body. The whale almost stops dead from the drag. Next, the whale closes its mouth and slowly contracts the throat, pushing the water out through the baleen plates that hang from its upper jaw. The krill are trapped on the baleen’s fringed inner edges and swallowed. Filtering a single mouthful takes about a minute. Then the whale accelerates again for the next lunge. On a typical deep dive a blue whale makes several lunges before surfacing to breathe. | Stage | What happens | Approximate time | | ----- | ------------ | ---------------- | | Search and dive | Descends to a dense krill patch, often 100–300 m | Several minutes | | Acceleration | Powerful tail strokes toward the swarm | A few seconds | | Engulfment | Jaw drops; throat pleats expand around a huge mouthful | Several seconds | | Filtration | Water pushed out through baleen; krill swallowed | About a minute | | Repeat | Several lunges, then surfacing to breathe | Dives often 10+ minutes | Baleen: the krill sieve Baleen whales have no teeth. Instead, rows of baleen plates hang from the upper jaw, made of keratin, the same protein as human fingernails. A blue whale has several hundred black plates on each side, each up to about a metre long, with a fringe of fine bristles on the inner edge. Together they form a mat that lets water out but keeps food in. Blue whale baleen bristles are relatively coarse compared with those of whales that eat smaller prey, such as right whales, which skim copepods. That coarseness suits krill, which are larger than copepods, and lets water escape quickly. For more on the crustaceans that baleen whales target, see [crustaceans eaten by whales](/crustaceans-eaten-by-whales/). ~30 mLength of the largest blue whales ~16 tUpper estimate of daily krill intake in peak season ~1 minTime to filter one mouthful How much krill does a blue whale eat? For decades, textbooks said a blue whale eats about four tonnes of krill a day. That figure was based mostly on stomach contents from whaling and on estimates of metabolic needs. More recent work, using tags to count lunges and echosounders to measure the density of krill patches the whales were feeding on, suggests the real figure in the feeding season can be much higher. A widely reported 2021 study led by Matthew Savoca estimated that a blue whale feeding off California might eat around 16 tonnes of krill a day during the feeding months. The key point is that blue whales do not eat at that rate all year. They feed intensively for several months in productive waters, building up blubber, and then travel to warmer waters where they eat much less, sometimes very little, while breeding and calving. A single successful lunge into a dense patch can deliver hundreds of kilograms of krill, and the whale needs many such lunges a day to make the effort pay. If krill patches are too thin, each lunge costs more energy than it returns, and the whale moves on. ![Dense Antarctic krill swarm under sea ice, where blue whales eating krill find their food](https://thesea.org/wp-content/uploads/blue-whales-eating-krill-2-thesea-org-by-blane-perun.webp)Dense Antarctic krill swarm under sea ice, where blue whales eating krill find their food Where blue whales find their krill Blue whales gather wherever krill concentrate. In the eastern North Pacific, the coast of California, including Monterey Bay and the Santa Barbara Channel, is a major summer and autumn feeding ground, fed by upwelling that brings nutrients to the surface and fuels phytoplankton blooms; see [phytoplankton blooms](/phytoplankton-bloom/). Antarctic blue whales feed on *Euphausia superba* around the edge of the sea ice in the southern summer. Pygmy blue whales feed in places such as the Bonney Upwelling off southern Australia. Some populations in the northern Indian Ocean, including off Sri Lanka, appear to stay in the region year-round. Krill rise toward the surface at night and sink by day, so blue whales follow them: diving deep during daylight and feeding nearer the surface at night or around dawn and dusk. Some studies have also suggested that whales can remember productive feeding areas from year to year rather than searching at random. Whales feed the krill too It is easy to see the relationship as one-way, but whales also help the krill they eat. Krill and phytoplankton in the Southern Ocean are often limited by iron. When whales feed at depth and then defecate near the surface, their faeces release iron and other nutrients that fertilise phytoplankton, which in turn feed krill. Researchers have proposed that the collapse of great whale populations during industrial whaling may have reduced this recycling, and that krill did not boom after whaling as expected partly because of it. This idea, sometimes called the “krill paradox”, is still being studied, but it is a good reminder that big predators shape the systems they live in. Our [what lives in the Southern Ocean](/what-lives-in-the-southern-ocean/) page covers that ecosystem. Threats to the krill-based diet Blue whales were hunted to the edge of extinction in the twentieth century, and although they have been protected since 1966, many populations remain well below their historical sizes; the species is listed as Endangered by the IUCN. Today the main threats are ship strikes, because feeding grounds such as the Santa Barbara Channel sit beside busy shipping lanes; underwater noise, which can disrupt feeding; and changes in krill. Warming waters, marine heatwaves and shrinking sea ice can all reduce or shift krill swarms. In the Southern Ocean, a commercial krill fishery operates under catch limits set by CCAMLR, and scientists continue to debate how to keep enough krill in the water for whales, penguins and seals as the climate changes. My take: scale is the whole story What strikes me about blue whales and krill is the scale mismatch, and how sensible it becomes once you understand it. In my reef tanks since 1996, I have always had to think about matching food to the animal: the right particle size for a filter feeder, the right amount so that nothing starves and nothing rots. The blue whale is the extreme version of that same problem. It has solved it by eating at the bottom of the food chain, in bulk, at exactly the places and times when the food is densest. If I were planning a trip specifically to see blue whales feeding, I would look at the California coast between roughly June and October, when krill concentrate along the shelf edge, and book with an operator that follows whale-watching guidelines and keeps its distance. Watching a 100-tonne animal live on centimetre-long crustaceans is the best lesson in ocean food webs you will ever get. ![Blue whale surfacing in krill-rich water off California, blue whales eating krill](https://thesea.org/wp-content/uploads/blue-whales-eating-krill-3-thesea-org-by-blane-perun.webp)Blue whale surfacing in krill-rich water off California, blue whales eating krill Frequently asked questions Do blue whales only eat krill? Almost entirely. They may swallow small amounts of other plankton, but krill make up nearly all of their diet. How much krill does a blue whale eat in a day? Older estimates said about 4 tonnes; recent studies suggest up to around 16 tonnes a day in peak feeding season. How do blue whales catch krill? By lunge feeding: engulfing a huge mouthful of water and krill, then filtering it through baleen. Do blue whales have teeth? No. They have baleen plates made of keratin instead of teeth. Do other whales eat krill? Yes. Fin, humpback, minke, sei and other baleen whales eat krill, often along with small fish. How can a blue whale survive on krill? Krill swarm densely and are rich in fat, and eating low on the food chain gives the whale far more energy. Sources & further reading - Goldbogen, J.A. et al. (2011). Mechanics, hydrodynamics and energetics of blue whale lunge feeding. *Journal of Experimental Biology* 214: 131–146. - Savoca, M.S. et al. (2021). Baleen whale prey consumption based on high-resolution foraging measurements. *Nature* 599: 85–90. - NOAA Fisheries: Blue whale species profile. - IUCN Red List: *Balaenoptera musculus*. - Australian Antarctic Division: Krill and whales. Continue reading More about krill and whales [WhalesBlue WhaleThe largest animal that has ever lived. ](/blue-whale/) [CrustaceansKrillThe tiny crustaceans that feed giants. ](/krill/) [PlanktonKrill vs ShrimpWhy krill are not tiny shrimp. ](/krill-vs-shrimp/) BP Last updated November 13, 2026 Written by Blane Perun Blane Perun has been exploring Earth’s oceans and marine life for over 25 years. Founder of TheSea.Org in 1999, underwater photographer, coral aquaculture pioneer, and explorer of 80+ countries. [About Blane Perun →](/about-blane-perun/) [More on krill →](/krill/)