Whales of Mystery: We know so little about beaked whales

Twenty-two species of beaked whales live ocean-wide. They inhabit waters from the tropics to the poles. For such a cosmopolitan family, little is known about beaked whales. So, what exactly are beaked whales, and why are they so hard to study?

The most mysterious cetaceans

Beaked whales belong to the Ziphiidae family. So-named for their narrow rostrums, which are similar to dolphin beaks. Also, like dolphins, beaked whales are odontocetes (toothed whales). However, they don’t have as many teeth as most odontocetes. Instead, beaked whales have a pair of tusk-like teeth. In females, the tusks do not grow past the gums and are never seen. In males, the tusks erupt past the jawline. Thus, males are easier to identify. Male beaked whales use their prominent teeth for male-male competition. They are analogous to antlers on deer. Evidence of such competition is seen as white scarring along with the bodies of male beaked whales.

Incredible divers

Beaked whales are also identified by a small, triangular dorsal fin located toward their bodies’ rear. Many beaked whales look very similar to each other and require a keen eye to identify correctly. This can make it challenging to study. However, the main reason beaked whales are hard to study is due to their elusive behavior. When found, they are offshore, searching for their prey in abyssal waters. A beaked whale may be at the surface for a few minutes and then disappear for hours at a time.

beaked whales are diving champions — These mysterious whales are among the deepest diving whales – Credit: Ana¨ïs Remili

The Cuvier’s beaked whale (Ziphius cavirostris) is the deepest diving marine mammal. A Cuvier’s beaked whale can reach depths of almost 3,000 meters (1.9 miles). That’s almost 8 times the length of the Empire State Building! They can also remain submerged for almost 4 hours at a time!

So what are they doing 2 miles underwater?

At that depth, scientists cannot observe the whales’ behavior. How do we find out what they are doing down there? Well, first, scientists have to find whales. Incredibly, after spending hours underwater, beaked whales only need a few minutes to recuperate before diving again. Therefore, to find these elusive whales, scientists rely on good ol’ fashion detective work. With nothing but a pair of binoculars, sturdy sea legs, and a little luck, scientists search miles of ocean to spot the whales. With only moments, scientists must identify the species, take pictures, and safely attach dive recorders to the whale (if they’re close enough). Dive recorders collect an incredible amount of data. While attached to the whale, they can record the dive’s depth and time, and even the whale’s speed. With this information, scientists can discover where the whales travel. And based on speed, they can even infer when a whale might be hunting!

What do they eat?

It’s too dark to attach a camera to the whale and spy on them while they hunt. The unfortunate answer comes from looking at stomach contents. A deceased whale, though sad, still offers a lot of information to scientists. A necropsy is performed to collect data, such as age, body measurements, and cause of death.

The remains in their stomachs help scientists identify and quantify what the whale ate. It takes an enormous amount of detective work. Scientists collect squid beaks, squid pens, and fish ear bones from the stomachs. With these remains, experts can identify the genus (and maybe even the species) of prey eaten and estimate their age based on size! When we know more about a species behavior, such as foraging, we can better protect them.

Two new species of beaked whale recently discovered!

In northern Japan, whalers have known of two kinds of beaked whales common to their waters. One type is Baird’s beaked whale (Berardius bairdii). They are the largest of the beaked whales, weighing over 20,000 pounds and reaching 35 feet. Due to their size, Cuvier’s beaked whales are the most commonly sighted beaked whale. Additionally, Baird’s beaked whales have a large range throughout the northern Pacific Ocean.

The second type is smaller than Baird’s beaked whale and black in color. It was clear that this was not Baird’s beaked whale but something different. However, the blowhole slit shape alerted scientists in 2019 to a possible relation to Baird’s beaked whales. Upon genetic analysis, scientists confirmed it to be part of the Berardius genus but a separate species! They named this new species Berardius minimus or Sato’s beaked whale.

Another potential species was just discovered in Baja, California (in November 2020). Genetic studies are underway to confirm the individuals belong to an undiscovered species. We wrote an article about it here.

There’s still more to be discovered!

Some might believe that there is nothing new to be discovered. Clearly, this isn’t true. Earth still has mysteries to be solved and needs scientists to research them.