When it comes to predator/prey relationships, the killer whale is an apex predator and isn’t known to have natural predators.
That is except humans, parasites, and diseases, which can significantly affect a killer whale’s health.
Lacking any natural predators of their own, these marine mammals can freely hunt and kill other oceanic creatures without the fear of being hunted themselves.
Like other dolphin species (killer whales belong to the dolphin family), they consume fish, squid, octopus, crustaceans, and cephalopods.
However, unlike other dolphins, killer whales also hunt other marine animals such as seals, sea lions, penguins, sharks, and even other cetaceans, including whales and dolphins (killer whales do eat other dolphins) and porpoises.
Despite being natural predators that eat other living mammals, killer whales do not appear interested in eating people.
In fact, there are no known cases of a killer whale consuming a person.
There are, however, a few cases of people being attacked in the wild, but these attacks are sporadic, and once the killer whale realized it wasn’t their typical food, they usually stop.
When hunting for food, these massive creatures can often be seen traveling in packs or pods using organized hunting strategies to isolate and immobilize their prey while minimizing their own chances of sustaining injuries.
For example, when hunting sharks, one or several killer whales may attempt to distract the shark while another killer whale sneaks up from behind or underneath the shark to ram it and flip it over.
Once the shark is flipped over, it becomes shocked and unable to attack, allowing the killer whales to attack their prey without the fear of being attacked themselves.
When hunting fast and agile prey such as dolphins, killer whales will work collectively to tire the dolphin out until they cannot swim away fast enough to escape.
They have even been spotted sneaking up to the beach or an iceberg using stealth and then quickly leaping out of the water and onto the sand or iceberg to surprise their prey and grab onto it before it can react and escape.
While other animals do not hunt these marine mammals, killer whales are well aware that some of their prey may try to defend themselves, which could lead to permanent injuries such as injured fins or the loss of an eye.
Because of this fact, killer whales are very cautious and methodical about their hunting methods to maximize their success rates while ensuring their safety.
Part of what makes killer whales such successful hunters and defenders are the closely-knit packs or groups they travel in and rarely separate from.
Killer whales are very family-oriented, and when one killer whale successfully captures its prey, the food is often split between family members and close friends.
Like with humans, the bonds of killer whales can last a lifetime.
These close bonds allow killer whales to work together when foraging and protect one another from potential threats from sharks and other marine animals that may put up a good fight when being attacked.
Defense measures
While the killer whale is an apex predator, it doesn’t mean other species will lie down and give up.
In fact, several other species will fight back to protect themselves and their families.
For example, female sperm whales occasionally face threats from hungry killer whales looking to steal their small children away for food.
To protect their children, the female sperm whales may form a circle around the child, using their flukes to hit any potential predators trying to enter the circle.
It has been said that the amount of power that their flukes can generate is enough to injure a lurking predator seriously and may even be lethal.
Sharks are also likely to put up a fight when being attacked and, if possible, may attempt to latch onto a predator and trash back and forth to wound and injure the predator.
With that said, only a small percentage of shark species are known to hunt large prey and form a proper defense.
Non-traditional predators
As stated earlier, the killer whale doesn’t face regular threats the way other ocean animals do.
However, they are not invincible and can become harmed, ill, or killed by other threats such as humans, parasites, and disease.
Humans
When it comes to being harmed by humans, the killer whale can be affected either directly or indirectly and intentionally or unintentionally, depending on the situation and interests of those involved.
Unintentional threats may include:
- Overfishing
- Fishing equipment
- Water contamination/waste
- Oil spills
- Noise pollution
- Ship/boat strikes
Intentional/deliberate threats may include:
- Illegal hunting
- Unauthorized capture for research
- Live capture for aquariums in some parts of the world
Unintentional Threats
Unintentional threats such as overfishing can cause serious issues for killer whale pods that rely on certain food stocks (particularly fish) for their survival.
Having to compete with commercial fishing companies for fish and other food sources may force killer whale pods to relocate or face starvation.
In addition to overfishing threats, killer whale pods may also be harmed by the fishing equipment used or discarded, such as fishing nets (intended for fish) and fishing lines.
Boat strikes from passing boats or ships may also cause serious harm to nearby killer whale populations, especially in highly commercialized areas.
Other threats include contamination from waste and harmful chemicals, oil spills from large ships and/or oil refineries, and noise pollution caused by loud aircraft, explosives, sonar, and other noisy equipment.
When it comes to noise pollution, it is believed that loud human-made sounds can affect the killer whales’ use of echolocation and may even cause brain hemorrhaging.
Extreme cases may lead to beached stranding and decompression sickness (Dysbarism), which is less common in marine mammals but still possible when rising to the surface too quickly.
Intentional Threats
Intentional threats such as illegal hunting, unauthorized research capture, and live capture for aquarium display are also known causes that can contribute to killer whales’ death.
Although these situations exist, they tend to be less common among killer whales than other whales/dolphin species.
In fact, illegal hunting, for example, is much less common among killer whale populations than among large baleen whales and some dolphin species as they may be both harder to capture and less financially rewarding.
When it comes to other species, both whales and dolphins are hunted for their meat, which depending on the country, may be sold for a premium in certain restaurants or grocery stores.
Dolphin meat has also been found in cans of tuna and other fish-related products to be used as a substitute for tuna.
While these threats may be less significant to killer whales than overfishing and pollution/contamination, they can still affect certain killer whale populations/pods with the added effect of being an intentional act.
Parasites
When it comes to parasites, most parasites have little effect on healthy killer whales.
However, sick or injured killer whales may be weakened or affected by living parasites that are hosts on their bodies.
Flukes, roundworms, and tapeworms have all been observed feasting on killer whales as well as fungal and bacterial infections.
Disease
As with all animals, killer whales can face threats from diseases and bacteria that can have dire consequences on their long-term health.
In some cases, these diseases may even lead to death.
Killer whales have been observed with several different diseases and medical issues such as Hodgkin’s disease, heart disease, skin diseases, stomach ulcers, tumors, and respiratory disorders.
In fact, reports of killer whales dying from the West Nile virus and St. Louis encephalitis have been recorded.
Interestingly these cases have only been observed in captive killer whales suggesting that their lowered immune system may have led to their deaths.