That’s a great question!
The only cetacea known to hunt, attack successfully, and eat sharks is the killer whale (possibly the false killer whale).
However, little is known or well-researched about the false killer whale species.
Killer whales are brilliant, highly organized, and very social and often hunt in groups together when searching for large prey.
These marine mammals have been known to attack and eat everything from small fish and turtles to squid, seals, sea lions, and even large whales.
Killer whales also hunt, attack, and eat sharks.
Some sharks recorded as being hunted by killer whales include hammerheads, makos, great whites, thrashers, and whale sharks.
As far as whales go, when other food sources are limited, killer whales will attack even the largest whale species.
Not much information has been recorded regarding killer whales eating a healthy living blue whale (the largest animal in existence)
However, they have been observed hunting and attacking weak blue whales and other smaller whales.
Some blue whales can be found with marks and scars from battles with killer whales.
Killer whales have also been observed attacking, killing, and eating sharks and will use a technique known as a “karate chop,” in which they drive the shark to the surface of the water and then lift their tail and slam it down on the shark, similar to a martial artist doing a karate chop.
The killer whale then grabs the shark and flips it over to incapacitate it, causing tonic immobility.
When a shark has quickly flipped over onto its stomach, it panics and becomes immobile, allowing the killer whale to attack it successfully.
Other techniques to attack sharks include multiple killer whales circling a shark, ramming it, and stealthy sneaking up from below and attacking the shark’s underbelly.
Killer whales are intelligent and cautious when hunting dangerous prey and will either attack in groups or use stealth to minimize their chances of being harmed.
Killer whales don’t always make sharks or whales a part of their primary diet, but when food becomes scarce and limited, these marine mammals will hunt other marine mammals regardless of their prey’s size.
Note: In some areas, killer whales primarily eat fish, while in others, marine mammals make up a large part of their diet.
Killer whales are commonly known as apex predators.
An apex predator is a predator that has no known predators of its own.
They can attack other marine mammals without the fear of being attacked, which puts them at the top of the food chain in the oceanic world.
Why Other Cetaceans Don’t Eat Sharks
There are several reasons other species of cetacea do not eat sharks. Note: Cetaceans include all species of whale, dolphin, and porpoise.
To illustrate, several characteristics prevent baleen whales from successfully hunting sharks.
First, baleen whales possess baleen plates instead of teeth. The lack of teeth prevents these large animals from chewing or tearing apart their prey.
And while the toothed whale suborder does possess teeth, many of them are not designed to consume predators such as sharks.
Not only is it harder for many of the toothed whale species to consume a shark, but they also face the threat of being attacked by the same animal they are hunting.
Because many species of cetacea prefer to minimize their risk of being harmed, it is safe to assume they’d rather hunt and consume prey that is likely to put up less of a fight or at least hunt prey that cannot harm them.
On the other hand, it is rare to see a shark hunting a dolphin or whale.
They also tend to hunt easier prey, and the thick blubber of some cetacea may prove too difficult to cause any significant harm to the cetacean they are pursuing.
Second, most species of cetacea (including large baleen whales) have small throats, which prevent them from swallowing a shark or large object.
For instance, the throat of a blue whale (the largest whale in the world) is less than one ft. wide.
Third, many species of cetacea have grown accustomed to eating certain types of prey.
While it is not well researched, the digestive system of these marine mammals may have adapted to the types of foods they currently consume, so trying to eat something that isn’t a regular part of their diet may cause digestive issues or pain, or it possible that their gustatory system (taste) is not interested in the taste of shark meat.
This third argument is just a hypothesis as it isn’t proven that the taste/digestive system prefers traditional foods and shark meat.
Rare occurrences of cetaceans swallowing sharks
While it is likely that most cetaceans do not actively hunt sharks, in rare occurrences, sharks or their parts have been found in the stomach contents of certain cetacean species (other than killer whales).
For instance, one study done on the stomach contents of sperm whales showed that in a small handful of subjects, they found sharks and shark parts in the bellies of these large marine mammals.
As far as we know, sperm whales hunt squid (not sharks).
However, they may swallow a shark or its body parts in sporadic instances.
As stated earlier, most cetaceans have throats too small to swallow a shark.
The sperm whale is an exception to this rule, as it has one of the largest (if not the largest) throats of all living cetaceans.
Sperm whales have been observed consuming giant squid even when they lose all of their teeth.
To a lesser degree, it may be possible for some cetaceans to coincidentally swallow a small shark (possibly a baby or small species of shark) while hunting their typical prey.
The likelihood of finding digested sharks in the stomach contents of most cetaceans (including sperm whales) is very low in general.