Orcas are a type of dolphin, and have gained the nickname the killer whale due to their massive size, and ability to kill giant animals like whales.
Orcas are highly intelligent, and being one of the smartest animals on earth, one place where you can see their brain at work is when hunting.
Often called the hunter of hunters, orcas not only eat sea life like fish, but also some of the top predators in the waters like sharks.
Behavior, anatomy, and their social bonds are factors that contribute to making the orca one of the top apex predators on earth.
In this article we will go over how orcas hunt, the tactics they may use, and other interesting things about their predatory dominance.
The majority of humans have only seen orcas in captivity, and while keeping these animals has been questionable ethically, working so closely with them we have managed to see just how intelligent they are.
It is estimated there are more than 50,000 orcas in the wild, and their dominance stretches the world’s ocean.
Let’s take a look at the diets, and hunting strategies used by one of earth’s top predators, the killer whale.
The Predator’s Physiology
Orcas (Orcinus orca) are the largest member of the Delphinidae, or dolphin family, and are one of the most recognizable of sea life due to their black and white coloring.
Like other sea mammals, orcas are sexually dimorphic, with males being larger, and heavier than females.
On average orcas have a length between 6 to 8 meters (20 to 26 ft.) when fully grown, but females typically grow between 5 to 7 meters (16 to 23 ft).
Fully grown orcas are massive, and weigh between 3 to 6 tonnes ( 3 to 5.9 long tonnes), with the largest orca ever recorded being more than 10 tonnes (9.8 long tonnes).
Killer whales have around 40 to 56 teeth which have a length around 7.62 cm (3 in.), and interlock.
Some estimates of the killer whale’s bite force are as high as 19,000 psi.
Found all over the world, orcas rule as far as down as1,000 meters (3,280 ft) deep, and have well developed eyesight.
Studies into their eyesight suggest these animals have visual activity with a 5.5 min of arc, and a stimulus intensity range of 10 to 20 ft. c, with their eyesight being one of their tools they use to hunt.
Killer whales also have echolocation, which can help detect fish, or other life by using sound waves, and clicks to see what echos bounce off of objects.
In dark waters echolocation is very useful, and lets them see up to 152.f meters (500 ft.) in front of them.
Sounds are also used by orcas to track down prey, and they can hear frequencies between 31 to 120 kHz.
The various senses and extremely powerful bodies are why orcas are easily the top predator in the ocean.
Strategic Pack Hunting
Since they live together in pods made up of family members, killer whales coordinate together when hunting, much like a pack of wolves, but in the sea.
Usually orca pods may get up to 15 members, but in times where they may congregate together like seasonal breeding they may group together in larger numbers.
Food availability is also a factor that may cause killer whales to congregate together.
Some of the foods that orcas eat include:
- Fish
- Squid
- Seals
- Birds
- Dolphins
- Porpoises
- Whales
- Dugongs
- Salmon
- Sea Turtles
Several methods like herding prey, using their tails to strike, or making large waves are used by pods to overwhelm prey before eating them.
Orcas use sounds to communicate with each other, and their intelligence allows them to have a large range of vocals, some even learning how to imitate humans, and say hello.
Calls, whistles, and pulses are used by killer whales to talk with each other.
At the top of the social hierarchy are older females who lead the pod, and males may occasionally join to breed.
Some orcas chase their prey inorder to corral them in an area.
They have also been seen knocking animals off of icebergs with waves, so their members can catch them when they fall in the water.
By isolating and overwhelming their prey killer whales use the other members in their pod to increase their chance in catching meals.
Agile Pursuit and Capture
Even with their large size, orcas are the second fastest marine mammal, and use their large tails to help them swim up to 56 km/h (34.8 mph) in the water.
Their robust bodies are tubular shaped, and their fin helps them regulate their heat while swimming.
When chasing down their prey orcas will ram, and bite at their potential meal to slow them down, or incapacitate them.
In a hunt jumping is a common tactic used by orcas to communicate with each other, and get a head start by leaping at their prey.
Killer whales are one of the most powerful animals in the ocean, and are even capable of leaping up to 4.5 meters (15 ft) out of the water.
Compared with other sea life, orcas have one of the highest jumps, and their nearly record breaking leap was captured when on a chase for a dolphin to eat.
Unlike other animals, orcas do not have a preference for when they are active, and sleep around 1 to 6 hours a day, active only when their prey is active.
In a day they can swim up to 64 to 144 kilometers (40 to 90 miles), and spend their time looking for food to eat.
In a day orcas eat up to 3 to 5% of their body weight, relying on their speed, and agile movement in the water to catch prey.
An orca jumping out of the water is one of the most iconic visual sights of the sea, and they often do this to celebrate a successful hunt, or increase their chance in capturing prey.
Adaptable Feeding Behaviors
Being apex predators, orcas have a very large diet that consists of life of many sizes.
The diet of an orca depends largely on where it lives, and the ecotype they are, with them usually only hunting what is most available.
For example Type 1 killer whales that live in the North Atlantic Ocean mainly eat fish and seals, while type 2 survive off minke whales, dolphins, and porpoises.
The diet, markings, color, size, and fin shape are some of the differences between orca ecotypes.
Here are the different types of killer whale ecotypes:
- Antarctica Type A
- Pack Ice
- Gerlache
- Ross Sea
- Subantarctic
- Eastern North Atlantic
- Type 1 Eastern North Atlantic
- Offshore Killer Whale
- Bigg’s Killer Whale
- Resident Killer Whale
Some killer whales like resident orcas mainly eat salmon, and travel in large numbers attacking other similar fish like steelhead, and halibut.
Male antarctica type killer whales are the largest of all types, while the smallest is the Antarctic type c.
Depending on what they eat, killer whales will choose the best strategy based on their prey.
Being apex predators, orcas will prey on anything they find from smaller fish, to whales that are bigger than them.
Some orcas specialize on prey in certain regions, and may not want to eat other animals.
Pods like the one that live near the coast of the western United States feed primarily on sharks, which is why their teeth often wear out quicker than those that feed on other animals.
Not only do killer whales have the ability to choose to feed on any animal they want in the water, but their diets are specialized to fit the region they live in.
Apex Predator Interactions
It is no question that orcas are the apex predator of the ocean, but living in such dangerous waters they often come across other animals that are also at the top of their food chain.
It is believed that orcas have no predators, but humans are their main threat.
In some regions around the world orcas are still hunted for their food, and blubber.
Things like pollution, global warming, and the decline of their food are potential threats to orcas.
Sharks, giant whales, large squids, and even other toothed whales are no match for the orca, and in most encounters they will either prey on, or ignore these animals.
In some cases orcas may even steal food from these animals, and they have even been sighted stealing fish from humans.
Sharks may seem like a potential threat to killer whales, but killer whales use their massive size to play with sharks like a volleyball, before feeding on their fatty livers.
Even when young orcas are safe from predators since the pods they live in provide an iron defense from outside predators.
Killer whale attacks on humans are very rare, with only a few instances occurring.
In captivity killer whales are more likely to attack humans due to the poor conditions they live in, and lack of mental stimulation.
Masterful Technique: Beaching Hunts
Leaping or breaching onto land is also a tactic used to get to animals like seals, or birds who try to escape the sea to prevent being eaten.
Beaching was also a trick that used to be done in marine orca shows, but these shows ended due to animal humanity concerns.
Like other marine mammals like dolphins, killer whales use lungs to breathe air, and rely on oxygen.
The blow hole located on the top of their head helps them breathe while submerged, and when out of the water orcas can survive up to 6 hours.
In the water orcas are only able to hold their breath underwater for around 15 minutes, so many pods have found ways to hunt while out of the water.
Around the waters of Punta Norte you may see killer whales beach themselves, to attack prey on land, to drag them into the sea.
Orcas in the beaches of Argentina are known for hunting on beaches, and will try to drag seals into the water when the tide is high.
If killer whales cannot get to a target on land they will circle them in the water, and try to use waves, or beach themselves to get them into the water.
The black and white coloring of the killer whale helps them sneak up on their prey whether they are chasing, ambushing, or beaching themselves to secure their meal.
On land, and in the sea, orcas use a variety of hunting tactics to feed on ocean animals.
Cultural Learning and Transmission
What an orca eats depends on where it lives, since the hunting techniques that orcas use are specific to where they live since they are passed down from generation to generation.
The way orcas pass down hunting techniques can be compared with humans with the different cultures around the world, and shows just how intelligent these animals are.
Living for around 50 to 90 years, orcas reach sexual maturity at around 14 years old, with most typically stopping to breed at around 40 years old.
Killer whales usually give birth to one calf at a time, with females able to give birth every 3 to 5 years.
Their gestation period lasts for around 15 to 18 months.
Since orcas are mammals, newborns rely on their mothers milk for the first 1 to 2 years of their life, before they are later taught how to hunt.
As they grow killer whales will begin to wean off of milk, and learn how to hunt from their mothers, and other members of their pod.
Sharing food is common amongst pod members, especially with mothers and their calves.
Each pod of orcas have their own culture of hunting, which is passed on from generation to generation, with the older and wiser whales leading the young.
Conclusion
Despite their killer nature there is a lot more to the orca than their amazing predatory hunting strategies, and traits.
As one of the smartest animals in the world killer whale shows used to be common, but their inhumane treatment, and difficulty having a fulfilling life in captivity is why keeping them is less common.
Today there are only around 54 orcas in captivity, and focus has shifted on discovering ways to maintain their numbers in the wild like keeping their homes stocked with food.
The intelligence, and social behavior of orcas make them unique in the animal kingdom, and also dominant predators.
There is still a lot to discover about orcas, and the more we learn about sea mammals the easier it is to see how similar they are to humans.
In the water there are a variety of types of orcas, and they have unique ways of hunting, using their knowledge and social skills to rule the waters as the top apex predator.
Sources:
- https://www.smithsonianmag.com/science-nature/understanding-orca-culture-12494696/
- https://www.fisheries.noaa.gov/species/killer-whale#:~:text=There%20are%20three%20main%20types,to%20interbreed%20with%20each%20other.
- https://seaworld.org/animals/all-about/killer-whale/communication/
- https://onlinelibrary.wiley.com/doi/full/10.1111/mms.12836
- https://en.wikipedia.org/wiki/Orca_types_and_populations
- https://www.reed.edu/biology/courses/BIO342/2015_syllabus/2014_WEBSITES/ceoesite5/adaptation.html
- https://cascadiaresearch.org/project_page/studying-diet-fish-eating-killer-whales-0/
- https://www.sciencedirect.com/science/article/abs/pii/0014488671900665#:~:text=The%20underwater%20visual%20acuity%20of%20the%20killer%20whale%20was%20estimated,in%20the%20guidance%20of%20behavior.
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