Humpback whale
A giant ocean mammal famous for breaching and long songs, following the food to Glacier Bay every summer to eat until its blubber is thick again.
Humpback whale at a glance
Megaptera novaeangliae HUMP-back whale; Megaptera novaeangliae is meh-GAP-ter-uh noh-vee-ANG-lee-ay
- Type
- Mammal · whale (rorqual)
- Diet
- Carnivore
- Size
- About as long as a school bus (40 to 50 feet) and as heavy as about 20 cars (up to 40 tons). A newborn calf is already about as long as a small car.
- Lifespan
- Humpbacks can live 80 to 90 years. A mother has one calf every 2 to 3 years after an 11-month pregnancy.
- Conservation
- Least concern (IUCN, global). Of 14 U.S. distinct population segments, 4 are endangered and 1 is threatened; the Hawaii whales that feed in Glacier Bay were recovered and delisted in 2016, but the species is still protected by the Marine Mammal Protection Act.
Eats capelin, herring, sand lance, krill, copepods
A humpback fasts all winter while it rests in warm water, then spends summer eating up to about a ton of food a day. One gulp can take in 15,000 gallons of water, which it pushes back out through baleen plates, swallowing the fish and krill that were caught.
Should you worry?
Humpbacks are not a danger to people on shore, and the rules here protect them, not you. In Alaska, boats must not approach within 100 yards of a whale at sea. On a tour boat, stay seated in your spot and follow the captain; never feed, touch, or chase a whale.
Out around the tidewater glaciers of Glacier Bay, a column of sea spray goes up like a signal fire, and then the whale follows. Humpbacks come here every summer to eat, and the first thing most people notice is the size. Even 100 yards off, which is the closest a boat may legally come, the whale is still the biggest thing in the picture: as long as a school bus, heavier than a house full of cars. The second thing to notice is the tail. Every humpback fluke is a one-of-a-kind black-and-white pattern, and the scientists who study this bay do not tag these whales; they photograph the tails. In summer 2013 Glacier Bay researchers identified 237 different humpbacks from fluke photos alone, and the same tails show up year after year.
The tail is not just an ID card. It is the whale’s diving brake. Before a deep dive, the humpback arches the broad hump of its back, the arch that gave it its name, then the flukes lift and the whale slides under, showing you the last thing it owns in the visible world. More than 28,000 North Pacific humpbacks were killed in the 1900s, and this bay’s whales were listed as endangered in the U.S. in 1973; today the same tail prints are photographed by the thousands in a recovering population that still needs its space, which is why the boat stays back and the whale keeps feeding. Watch for the blow, count the rhythm of the arch, and if you get a good look at the tail, you have seen something wearing its name badge.
Did you know?
- Every humpback's tail is a one-of-a-kind black-and-white fingerprint, and Glacier Bay researchers use photos of them to name and count the whales, identifying 237 different individuals in summer 2013.
- In 1899 nobody recorded a humpback in Glacier Bay; by the 1930s they were common there. The bay grew the whales along with its recovering glaciers.
- A humpback's blow shoots out of its two nostrils in a cloudy column that can be seen for miles.
Common questions
Why do humpback whales arch their backs before a deep dive?
The arch is the hump that gives the whale its name. It rises high, then the flukes lift and the whale goes under.
Why are there so many humpbacks in Glacier Bay?
Food. They fast all winter, then spend summer gorging on the fish and krill of the cold, rich water, which the NPS calls a humpback sanctuary.
Do humpbacks really sing?
Males sing long, repeating songs, mostly on the winter breeding grounds; one song can last 20 minutes or much longer.
Did whalers nearly wipe humpbacks out?
Yes. Over 28,000 North Pacific humpbacks were killed in the 1900s. The species was listed as endangered in the U.S. in 1973 and has been recovering since.