Size and weight
An adult North Pacific humpback is 40 to 50 feet long and weighs 25 to 40 tons. Females are a little larger than males, which is the rule among baleen whales. The largest confirmed humpbacks approach 60 feet, about the length of a city bus and a half, and 40 tons is roughly the weight of six adult elephants or 25 pickup trucks.
The pectoral fins, or flippers, are what make a humpback a humpback: the genus name Megaptera means big wing. They reach 15 feet, about a third of the body, and no other whale comes close. In Hawaiʻi most whales have flippers that are dark on top and white underneath. The bumps along their leading edge, called tubercles, cut drag and let a 40-ton animal turn tightly enough to corral fish and dodge a rival.
A newborn calf is 13 to 16 feet long and weighs around a ton. It drinks about 100 gallons of milk a day that is roughly 40 percent fat, and gains close to 100 pounds a day through the winter. By the time it swims north in April it may be 25 feet long.
How long they live
NOAA puts the lifespan at 80 to 90 years. Age is read from ear-wax plugs, which lay down a layer a year like tree rings, and from genetic tests. Females reach sexual maturity between about 5 and 10 years old and then calve every two to three years for the rest of their lives, though annual calving has been recorded. Whales photographed off Maui in the 1970s by the first researchers were still being seen in the 2010s.
What they eat, and why they do not eat here
Humpbacks are baleen whales. Instead of teeth they have 270 to 400 plates of baleen, a fingernail-like material, hanging from the upper jaw. A feeding whale lunges through a school of krill, herring or sand lance with its mouth open, its throat pleats ballooning to take in thousands of gallons of water, then pushes the water out through the baleen and swallows what is left. In Alaska they also blow curtains of bubbles to herd fish into a tight ball, a trick called bubble-net feeding that groups of whales coordinate.
There is almost nothing for a humpback to eat in Hawaiʻi. The clear blue water that makes Maui beautiful is clear because it is nutrient-poor. So the whales do not eat from the time they leave Alaska until they return, four to six months later. An adult may lose a quarter of its body weight. A nursing mother loses far more. That is why the whales you see in Maui are doing exactly three things: breeding, calving, and nursing.
Why they come to Hawaiʻi
Warm water (74 to 80°F in winter), shallow banks protected from ocean swell, exceptional visibility, and no resident orcas. A calf is born with little blubber and would lose too much heat in the Gulf of Alaska in January. The shallow basin inside the four islands of Maui Nui, with the ʻAuʻau Channel at its heart, is less than 300 feet deep across most of its area and is the single densest humpback breeding ground in the United States. More than half of the whole North Pacific population comes to Hawaiʻi, and Maui gets the biggest share.
How many there are
Commercial whaling took the North Pacific humpback population down to perhaps 1,400 animals by the time hunting ended in 1966. Protection under the Marine Mammal Protection Act (1972) and the Endangered Species Act (1973), and the creation of the Hawaiian Islands Humpback Whale National Marine Sanctuary in 1992, let it recover. NOAA now estimates more than 10,000 humpbacks winter in Hawaiʻi, and in 2016 the Hawaiʻi population was recovered enough to be removed from the endangered species list. It remains fully protected under the Marine Mammal Protection Act and the sanctuary’s rules, including the 100-yard approach limit.
How to tell them apart
Every humpback carries its ID on the underside of its tail. The pattern of black and white on the flukes, with its notches, scars and barnacle marks, is unique and stays recognizable for life. Researchers have been photographing Maui’s flukes since the 1970s, and the Happywhale project now matches tourist photos against a catalog of more than 100,000 whales worldwide. Upload a sharp fluke photo from your trip and you may learn that the whale you saw off Kāʻanapali was photographed in Glacier Bay last July.
Quick facts
| Scientific name | Megaptera novaeangliae (North Pacific population, Hawaiʻi breeding stock) |
| Hawaiian name | Koholā |
| Length | 40–50 ft typical, up to about 60 ft |
| Weight | 25–40 tons |
| Flipper length | Up to 15 ft, a third of the body |
| Lifespan | 80–90 years |
| Gestation | About 11 months |
| Calf at birth | 13–16 ft, about 1 ton |
| Dive time | Usually 5–15 minutes; up to about 30 |
| Speed | 3–9 mph cruising, 15+ mph in bursts |
| Diet | Krill, herring, sand lance, capelin, juvenile pollock (in Alaska only) |
| Status | Delisted from the ESA (Hawaiʻi population, 2016); protected under the MMPA |
Sources: NOAA Fisheries humpback whale species profile; Hawaiian Islands Humpback Whale National Marine Sanctuary; Pacific Whale Foundation; Whale Trust Maui.
See them from the water
We recommend two West Maui operators: Maui Whale Adventures for a 20-guest raft at eye level with the water (from $79), and Teralani's Premium Whale Watch for a sailing catamaran with lunch and an open bar (from $154.95). Both load from Kāʻanapali Beach and guarantee sightings. Compare them →
