Sharks do eat octopuses, but it depends on the species and where they live. Although sharks are apex predators, meaning they have no natural predators and will consume almost any animal under the sea, the specific diet varies greatly based on the individual shark.
This is seen even amongst prey of the same taxonomic class.
Octopuses are part of the Mollusk (or Mollusca) phylum, which also includes other shelled organisms such as clams and oysters.
However, based on the shark and its habitat, they can consume anything as small as an oyster to something as large as an octopus or squid.
We know this because some sharks have even been found with squid beaks still in their stomachs!
Now, to prove my point and be a bit more specific, let’s take a look at some specific species of sharks that are known to consume octopuses and what the natural predators of octopuses are.
What Kind of Sharks Eat Octopuses?
Some shark species known to eat octopuses include dogfish sharks, whitetip reef sharks, nurse sharks, and the relatively larger hammerhead sharks.
Although sharks, on average, prefer fish as their primary choice of prey, these shark species share similar ecosystems that allow them to include octopus on their palate as well.
Diet of the Dogfish Shark
The dogfish shark is a relatively small shark that is known for consuming squid and octopuses, among other fish and invertebrates.
Overall, the dogfish shark is an opportunistic feeder, meaning it will consume anything that it happens to come across.
Because they’re opportunistic feeders, along with the fact that proper management and regulations are in place, the dogfish shark population in the Pacific Coast is above the target level.
Another interesting fact about the dogfish shark is that, because they’re small, the roles of predator and prey are sometimes reversed, and the dogfish instead becomes prey for the octopus.
Diet of the Whitetip Reef Shark
The whitetip reef shark is another small shark known for consuming mollusks such as octopus, as well as other reef fish and bottom-dwelling fish.
As its name suggests, the whitetip reef shark likes to spend much of its time on the ocean floor and around coral reefs due to its nocturnal lifestyle.
Because it’s nocturnal, the whitetip reef shark will hunt at night close to the ocean floor, where most of the marine animals go for the night.
This is advantageous to the shark because its slim body and snout allow it to wedge itself into tight spaces (such as those of coral reefs) and catch whatever has hidden within, such as octopuses and smaller fish.
Unlike the dogfish shark, the whitetip reef shark is considered Near Threatened on the IUCN Red List due to a combination of overfishing, bycatch (owing to their habit of spending time at shallow waters) and the lack of proper management and conservation regulations.
Diet of the Nurse Shark
Like the whitetip reef shark, the nurse shark is a nocturnal shark known to prey on invertebrates (i.e. lobsters, shrimps, squids, octopuses) and fish (i.e. mullets, puffers, stingrays) close to the ocean floor.
When it comes to feeding, the nurse shark is different from the whitetip reef shark in that, instead of cramming itself into tight spaces using its body, the nurse shark will use its mouth like a vacuum and suck in whatever prey it can find along the ocean floor.
To help it on its search for food, the nurse shark has two unique sensory organs called “barbels” located under its mouth.
Diet of the Hammerhead Shark
The hammerhead shark, the final shark in our exploration today, is another shark that is known to consume benthic animals, such as octopuses.
It is also the largest of the bunch. They can reach a length of 20 feet (6.1 meters) and weigh nearly 1,000 pounds (450 kg)!
The hammerhead shark feeds on cephalopods, such as squid and octopuses, because, like the nurse and whitetip reef sharks, it also likes to stay near the ocean floor.
Due to their unique head structure, hammerhead sharks can use the sides of their head to pin down animals to the ocean floor while consuming them.
Since hammerhead sharks are quite large, they don’t have any natural predators.
Despite this, they’re still considered endangered by the IUCN due to a combination of commercial fishing (their large fins are highly valued) and their high mortality rate once taken out of the water.
What is the Natural Predator of the Octopus?
Certain birds, whales (i.e. sperm whales), and fish species (remember that sharks are fish) are all considered the primary predators of octopuses. Depending on where you look, there may be other predators such as the larger moray eels, seals, and sea otters.
When I say birds, I am mainly talking about seabirds (not seagulls) that are large enough to dive down and catch octopuses (since octopus primarily spend their time on the ocean floor), such as penguins or petrels.
Believe it or not, baleen whales can eat octopus just as well as toothed whales, though often they’re much smaller since baleen whales can’t chew them. As such, it’s not strange to find out that the sperm whale, the largest of the toothed whales, often prefers octopus on its menu.
As for fish, I think you already know enough of it from this article (again, because sharks are fish).
Sharks and octopus sure do make an unlikely duo, don’t they? Although it might’ve been hard to believe at first, I think it all starts to make sense once you realize that some sharks and octopuses share the same living spaces.
If you intend to do some investigative fieldwork into this, might I suggest taking some scuba diving lessons first?