Hawaii’s Beaked Whales

Sensitive beaked whales are well-adapted to be deep divers

Whales and dolphins that have teeth and hunt other animals (as opposed to baleen whales, which scoop up plankton or schools of small fish) tend to stick to the upper 1500 feet of the water column, as do predatory fish like tiger sharks and bluefin tuna. But beaked whales, which have beak-like pointed ‘snouts’, have evolved in a unique way. They developed collapsing lungs and other traits that enable them to routinely dive to 5,000 feet, where the water pressure is 1,500 pounds per square inch (!) and not much above freezing, making them the deepest diving air-breathing animals known.

At such depths, the water contains so little oxygen, that everything moves around in slow motion. The beaked whale hunting dives can last up to 90 minutes and average one hour in length. Using their bat-like clicking sonar locators (it’s pitch dark down there), they are able to scoop up squid and fish with ease without competition. The down side: to avoid nitrogen bubbles, known as the bends, they need to come up very carefully.

Beaked whales are so difficult to observe that some have never been seen alive and only a few have been studied in detail. In addition to having a “beak” of differing lengths, beaked whales also have flipper pockets – depressions in the body wall into which their large flippers can be tucked. Males of the species have only a single pair of teeth with some resembling tusks. Females and juveniles are toothless!

New species of toothed whales are still being discovered.

Eleven species have been described since 1990. Seven new species of beaked whales, family Ziphiidae, have been discovered in the 1900s. These secretive whales have just begun to reveal their habits. The most recent species of beaked whales, Mesoplodon peruvianus, was described in 1991 with an even more recent discovery in 2016, thanks to advances  in DNA sequencing. This animal, in the genus Berardius, looks far different than its nearest relative and inhabits an area of the North Pacific where marine mammal research has been conducted for decades. And yet another beaked whale species  discovered in late 2019.

Blainville's Beaked Whale on whale watching tour near Ko Olina

Blainville’s Beaked Whale

Scientific Name: Mesoplodon densirostris

The most common  beaked whale to Hawaii is the Blainville’s beaked whales who are present off the Waianae Coast of Oahu for prolonged periods annually. They are regularly sighted in slope areas of 500 – 1000 m deep, with even deeper gullies nearby. about 14 feet long. The scientists estimate that about 140 individuals live in our (West Oahu) vicinity.

The male Blainville’s beaked whale is very odd looking. They have a pair of massive teeth protruding from bulges on the lower jaw that may become encrusted with barnacles. The females’ teeth do not erupt but they do still have the bulges on the jaw. The jawbone of the Blainville’s beaked whale has a greater density than elephant ivory. This gives rise to one of its common names; the dense-beaked whale.

Blainville’s beaked whales perform short dive sequences at 15 – 20 second intervals followed by deep dives of up to 45 minutes duration. On surfacing the beak points skyward. After taking a breath, the beak is sometimes slapped on the surface and the animal may roll slightly before disappearing. Their blow or spout is small but can be seen on a clear day to project forward.

Blainville’s Beaked Whale images from Wild Side charters.

cuviers size comparison

Cuvier’s Beaked Whale

Scientific Name: Ziphius cavirostris

The second most commonly found in Hawaii is the Cuvier’s, 9 feet long, with about 55 individuals here. Cuvier’s beaked whales appear to be one of the most abundant of the beaked whale family overall. Their foreheads slope gently to a slight beak that becomes less obvious cuviers size comparisonwith age. They have two teeth that are just visible when the mouth is closed.

Cuvier’s beaked whales tend to travel alone (especially older males) or in groups of about 10. They are not acrobatic animals although they have been observed breaching. Their blow is not noticeable unless they have just completed a long dive. Their dives usually last from 20 to 40 minutes.

Hawaii’s third beaked whale, Longman’s, is seen less often and needs more study.

The beaked whales’ distinction is in their teeth and jaws.

Beaked whales are considered toothed whales, but females’ teeth never erupt from the gums and males generally have only two teeth. In several species the teeth rise from the gum of the lower jaw, like tusks, at the front or sides of the mouth.

Sometimes the protruding teeth point a little forward, but mostly they stick up. Gooseneck (aka stalked) barnacles tend to grow on the constantly exposed teeth, causing the whale to look like it has a bunch of feathery flowers sprouting from each side of its mouth.

But there’s nothing feathery about the stems in those bouquets. Judging from the extensive long, crisscross scars on the males’ bodies, researchers believe that the males use their tusklike teeth in fights with other males.

Excerpted from Susan Scott’s Beaked Whales are not Rare, but are Seldom Seen in Hawaiian Waters

Blainville's Beaked Whale, Hawaii - scarred and stalked gooseneck barnacles

Why aren’t Hawaii beaked whales beaching from sonar exercises ?

Out of 40 mass strandings recorded since a new, more powerful sonar was introduced worldwide in the early 1960s, 28 were simultaneous with such exercises,  killing 206 beaked whales and 8 individuals of other species, according to a 2007 study by L. Weilgart of Dalhousie University in Nova Scotia.

Autopsies of stranded whales suggest they were so disturbed by mid-range sonar during the naval exercises that they surfaced too fast, dying of the bends. Examining six cases between 1985 and 2004 in the Canary Islands, Baird and Faerber (2010) found that in most cases, juveniles were overrepresented, suggesting some adults may get used to the sonar but juveniles may be more likely to panic when they hear it for the first time.

  • It’s not that Hawaii beaked whales aren’t affected; it’s that due to Hawaii’s isolation and diminutive size (the likelihood to wash ashore) we wouldn’t see the dead whales if they were.
  • Hawaiian shorelines are more dominated by steep cliffs and human population per kilometer of shoreline is lower than areas where other sonar caused strandings have occurred.
  • The fact that it has taken 30 years to discover a link between naval exercises and strandings (the first paper to do so, in the journal Nature, dates from 1991) underscores how easy it is to miss such impacts from human activities.

“The absence of evidence is not evidence of absence.”

Faerber, M.M., and R.W. Baird. 2010. Does a lack of observed beaked whale strandings in military exercise areas mean no impacts have occurred? A comparison of stranding and detection probabilities in the Canary and Hawaiian IslandsMarine Mammal Science 26:602-613)

Our whale watching tours focus on education and conservation so that an interactive relationship can be maintained in the best interest of both humans and dolphins. We strive to foster admiration and deep respect for these wonder-ful marine mammals.