Whale Skull: What It Looks Like, How Big It Gets and Where to See One

The first question to ask of any whale skull is whether it held baleen or teeth. Baleen whales, or mysticetes, include the blue whale (*Balaenoptera musculus*), the humpback (*Megaptera novaeangliae*), the gray whale (*Eschrichtius robustus*) and the bowhead (*Balaena mysticetus*). The Natural History Museum in London explains that these whales have broad rostra, the long snout section of the skull, and no functional teeth. Instead, their upper jaws carry plates of baleen, made of keratin, that filter food out of the water.

Toothed whales, or odontocetes, include the sperm whale (*Physeter macrocephalus*), the dolphins and the orca (*Orcinus orca*). Their skulls generally have teeth or empty tooth sockets, narrower rostra and more heavily modified nasal passages.

On a beach or in a collection, that first split narrows things down fast. A wide, flat, toothless snout points to a baleen whale. A row of teeth or sockets points to a toothed whale. Naming the exact species is a job for a museum or for NOAA.

Both groups breathe through blowholes on top of the head. Baleen whales have two openings and toothed whales have one, according to Smithsonian Ocean. The blowhole itself is soft tissue, though, so a cleaned skull shows only the bony nasal openings underneath.

Those openings sit where they do because of telescoping. G. S. Miller's 1923 study describes how the skull bones overlap and shift in different patterns in different whales. In baleen whales, the maxilla, the main bone of the upper jaw, keeps a broad plate that extends back over the eye socket. Toothed whales lack that plate and often have a more slender, beak-like rostrum.

Toothed whales add one more oddity: their skulls are commonly asymmetrical, with the left and right sides shaped differently. The Natural History Museum's work on whale skull evolution links this asymmetry to echolocation, the way toothed whales use sound to find their way and their food. Sperm whale skulls are especially lopsided. A human skull, by contrast, is close to a mirror image of itself from side to side.

The blue whale has the largest skull of any living whale. The juvenile at the New Bedford Whaling Museum came from a 66-foot animal that came ashore in Rhode Island in March 1998, and its skull and lower jaw alone stretch about 18 feet and weigh roughly one and a half tons.

A full-grown blue whale is bigger still. Hope, the blue whale skeleton at the Natural History Museum in London, measures 25.2 metres and weighs 4,500 kilograms. She came from a whale found beached in Wexford, Ireland, in March 1891.

Other baleen whales come smaller. A Mexican cetacean biology manual published through SEMARNAT, Mexico's environment ministry, gives a gray whale skull a length of approximately 2.5 metres.

Among the toothed whales, the sperm whale is the giant. Manchester Museum notes that sperm whales can grow to around 19 metres, and its own skeleton came from a whale that stranded on the Massachusetts coast. For an exact skull measurement of any one sperm whale on display, ask the museum that holds it.

An orca is a dolphin, zoologically speaking. The Australian Museum places *Orcinus orca* in the dolphin family, Delphinidae, and calls it the family's largest member, reaching about 9 metres and 5 tonnes. Its skull is a classic toothed whale skull: large pointed teeth, a rounded braincase and a relatively short, indistinct beak.

One real example gives a sense of scale. A Te Papa Tongarewa collection loan record lists a killer whale skull, jaws and teeth collected from a stranding at Allports Island, Queen Charlotte's Sound, New Zealand, on 3 July 1994. The skull measures approximately 300 millimetres high, 350 millimetres wide and 1,300 millimetres deep.

Smaller dolphin skulls vary a great deal. Many have long, narrow rostra. Natural History Museum researcher Agnese Lanzetti and colleagues showed that porpoises keep comparatively symmetrical skulls, unlike many other toothed whales and dolphins. River dolphins such as the baiji (*Lipotes vexillifer*) have especially long, thin beaks, as the Natural History Museum's baiji profile shows.

Museums are the best place to stand next to a whale skull, and several show them as part of full skeletons.

At the Natural History Museum in London, Hope, the 25.2-metre blue whale, has hung in Hintze Hall since 2017, her skull and jaw visible as part of the complete skeleton. The New Bedford Whaling Museum in Massachusetts displays the skull and lower jaw of its 66-foot juvenile blue whale with the rest of the specimen.

In Sydney, the Australian Museum has suspended the skeleton of a 17.4-metre male sperm whale since 1910; the whale stranded at Tom Thumb Lagoon near Port Kembla on 13 November 1871. Manchester Museum's young sperm whale skeleton has been on display since it arrived in 1898, two years after the animal stranded in Massachusetts.

At Whales of Iceland in Húsavík, the skeleton of a 25-metre female blue whale that washed ashore in Iceland in 2010 is on display. The Western Australian Museum in Perth reassembled its blue whale, Otto, in Hackett Hall after a four-year conservation and installation project. And the South Australian Museum in Adelaide says its first large prepared skeleton, a 17-metre sperm whale, is still on show.

Opening hours and gallery layouts change, so check the museum's own website before you go.

This part is general information, not legal advice. The plain answer first: do not take a whale skull or bone home from the beach. The simplest step is to leave it in place and report it to the NOAA Fisheries Stranding Network or NOAA, which can tell you what applies to that particular bone.

In the United States, marine mammals are protected under the Marine Mammal Protection Act, enacted on 21 December 1972. NOAA Fisheries sets out the rules for beach-found parts on its protected species parts page:

• Parts may not be collected from a carcass or from remains with soft tissue still attached. A dead animal with soft tissue should be reported to the NOAA Fisheries Stranding Network, and NOAA asks people not to move stranded whales, dolphins or porpoises.
• Parts from species listed under the Endangered Species Act, including sperm whales, may not be collected without authorization.
• Bones, teeth or ivory from a marine mammal that is not ESA-listed, found on a beach or on land within a quarter mile of an ocean, bay or estuary, may be kept only after they are identified and registered with the nearest NOAA Fisheries office.
• Marine mammal parts may not be bought or sold.

Local, state, tribal, park and international rules can add restrictions on top of these. Outside the United States, contact the wildlife or marine-mammal authority for the country, state or territory where the bone washed up. Our page on finding an animal skull covers the general questions, and the sea otter section of our otter skull guide shows how another protected marine mammal is handled.

A few quick answers for anyone still standing under the skeleton.

A whale skull is two stories in one bone: telescoped bones that overlap and shift as the skull adapted to water, and either a broad baleen jaw or a lopsided, toothed one linked to echolocation. The biggest belong to blue whales, with a juvenile's skull and jaw already about 18 feet long, and the best way to stand beside one is in a museum. If whale-sized skulls are your thing, our stories on the mammoth skull and the elephant skull and the Cyclops cover two more giants, and the Skeleton Coast is another shoreline where bones meet the sea.

---