Blue Whale Coloring Page: Free Printable PDF Sheet for Kids

Blue Whales: The Largest Animals on Earth

Scale and Body Structure

The blue whale (Balaenoptera musculus) holds the record as the largest animal ever known to have existed on Earth — larger than any dinosaur. Adults routinely measure 80 to 100 feet from the tip of the snout to the notch of the tail flukes. Females grow slightly larger than males, as in most baleen whales. Body weight typically falls between 100 and 200 tons, though exceptional individuals may exceed that range. The heart of an adult blue whale can weigh over 1,300 pounds and is large enough for a human to crawl through the aorta. The blood vessels that supply the muscles are so wide that a full-grown trout could swim through them.

Despite this mass, blue whales are built for sustained ocean travel. The sleek, elongated body — far more tapered than the stocky sperm whale — reduces drag in open water. Two small pectoral flippers on the forward body provide steering. A tiny dorsal fin sits roughly three-quarters of the way toward the tail and functions as a stabilizer. The broad horizontal flukes of the tail generate all propulsive thrust through up-and-down oscillation, unlike fish, whose tails move side to side.

Filter Feeding and Krill Consumption

Blue whales are baleen whales, meaning they filter food from seawater rather than catching individual prey with teeth. Inside the mouth, hundreds of plates of baleen — a stiff keratin material similar to human fingernails — hang from the upper jaw in overlapping rows. When feeding, a blue whale opens its enormous mouth, lunges through a dense krill swarm, and engulfs many tons of water in a single accelerating rush. Muscles then force the water back out through the baleen plates, trapping krill inside. A single blue whale consumes approximately 40 million krill per day during peak feeding season — roughly four tons of food daily. The feeding lunge shown in this coloring page, with the baleen lines visible along the lower jaw, is the defining feeding behavior of all rorqual whales.

The Blowhole and Breathing

Like all cetaceans, blue whales breathe air through nostrils that have migrated over millions of years of evolution to the top of the skull, forming the blowhole. When a blue whale exhales at the surface after a deep dive, the warm moist breath condenses and shoots upward in a tall column — the distinctive spout visible in this coloring page. A blue whale's spout can reach 30 feet high and is visible from several miles away. Blue whales have two blowholes — most toothed whales have one — and the paired blowhole is a key identification marker for whale-watchers. After surfacing to breathe several times, a blue whale arches its back and raises the small dorsal fin before a deep dive that may last 10 to 20 minutes.

Migration and Seasonal Range

Blue whales undertake some of the longest migrations of any mammal, traveling between polar feeding grounds in summer and tropical breeding grounds in winter. North Pacific blue whales spend summers feeding in the rich krill fields off California and Alaska, then move south toward warmer equatorial waters during fall. Southern Hemisphere populations follow the opposite seasonal pattern, feeding near Antarctica in the austral summer. Satellite tags have tracked individual blue whales crossing entire ocean basins, covering more than 10,000 miles in a single year. Despite these movements, blue whale populations tend to return to the same feeding sites year after year, suggesting strong spatial memory.

Conservation and Recovery

Commercial whaling in the 20th century reduced blue whale populations from an estimated 250,000 to as few as 5,000 animals by the time international protections took effect in 1966. The global population has recovered partially since the whaling ban, with current estimates ranging from 10,000 to 25,000 individuals, but recovery has been slow because blue whales do not reach sexual maturity until age 5 to 15 and typically give birth to one calf every two to three years. The primary threats today include ship strikes — blue whales surface in predictable shipping lanes — and low-frequency underwater noise from commercial shipping, which interferes with the long-distance calls blue whales use to locate mates across ocean basins.