False Killer Whale vs Orca: Key Differences and Similarities

Despite their similar names and physical characteristics that lead to common confusion, false killer whales and orcas (also known as killer whales) are distinct species within the dolphin family.

False killer whales are marked by their elongated bodies and a dorsal fin that is more curved and shorter compared to the tall, straight dorsal fin of the orcas. They share the aquatic ecosystem where their behaviors and interactions with other marine life reveal fascinating aspects of their nature and social structure.

The matter of differentiation between these two species becomes crucial when understanding their roles in marine biology and the importance of their conservation.

Key Takeaways

  • False killer whales and orcas are both in the dolphin family but have distinctive physical characteristics.
  • Confusion often arises between the two species because of similarities in name and appearance.
  • Understanding the differences is critical for marine biology and the conservation of these creatures.

What Are False Killer Whales?

Pseudorca crassidens, or false killer whales, are a species of oceanic dolphin belonging to the family Delphinidae. Despite their name including “killer whale”, they are not closely related to the killer whale (Orcinus orca). Their name stems from similarities in their skull shape to that of killer whales, which was first noted when the species was described from a fossil skull in 1846

False killer whales are large members of the dolphin family, not whales. They are generally dark gray or black in color, with some lighter gray patches on the throat, chest, and sides of the face in some individuals. They have a slender body and an elongated, tapered head.

False killer whales inhabit tropical, subtropical, and occasionally temperate waters worldwide. They are usually found offshore in deep, open ocean waters but can be seen in coastal regions near oceanic islands. Distinct populations exist near Hawaii and in the eastern North Pacific.

In terms of behavior, false killer whales are notable for their sophisticated cooperative hunting techniques. They primarily feed on fish and squid, and are known to share their catch with others in their group.

Their social structure is complex and cohesive; they form pods that can range from a few individuals to over a hundred. Their social behavior is characterized by strong bonds within the pod, often seen in the way they care for sick or injured members.

This level of social connection extends beyond their species, as they have been observed interacting with other marine mammals, such as bottlenose dolphins.

These mammals are intelligent and playful, often engaging in acrobatics such as breaching and tail-slapping. Their vocalizations, a series of high-pitched whistles and clicks, are used for communication and navigation through echolocation.

What Are Orcas (Killer Whales)?

Orcas, also known as killer whales, are large predatory marine mammals that belong to the oceanic dolphin family Delphinidae. Their scientific name is Orcinus orca.

Global Distribution and Ecotypes

Orcas can be found in every ocean in the world, from the frigid Arctic and Antarctic regions to tropical seas. They are highly adaptable creatures and have been documented in various habitats, including coastal areas and open seas.

There are several genetically and behaviorally distinct forms of orcas called ecotypes:

  • Resident orcas: Fish-eating orcas that live in specific coastal areas like the northeast Pacific.
  • Transient/Bigg’s orcas: Travel widely and primarily hunt marine mammals like seals. They are also found in the northeast Pacific.
  • Offshore orcas: Found in deeper waters and likely eat fish. Little is known about their diet.
  • Subantarctic orcas: A little known ecotype that has been sighted stealing fish from longlines.
  • Type B and C orcas: Distinctive ecotypes found near the Antarctic peninsula. They likely eat fish.

Type B killer whales, also known as Antarctic or Gerlache orcas, can be further divided into two forms: the larger Type B1 and the smaller Type B2.

Type C killer whales, sometimes referred to as Ross Sea orcas.

Social Structure and Hunting

Orcas live in tightly knit matrilineal family groups called pods, which typically consist of 2 to 15 individuals but can sometimes congregate in the hundreds. Pods comprise several matrilines, with each matriline consisting of a female orca and her offspring. The eldest female, called the matriarch, leads the pod.

For example, the Northern Resident community in British Columbia has over 300 orcas divided into at least 16 pods and 3 clans or acoustic lineages.

Offspring usually stay with their mothers for life, and pods often travel together, demonstrating the highly social nature of orcas.

When it comes to hunting, orcas are intelligent, strategic hunters that make use of complex cooperative techniques tailored to their prey. They locate prey through echolocation and then herd them towards shore or ice floes to limit their escape routes.

For example, some orcas have been observed working together to create waves that wash seals off ice floes into the water.

Their sophisticated hunting behaviors, along with their size and strength, have earned orcas their nickname, “killer” whales. Yet despite this moniker, they are generally not considered a threat to humans.

How Do False Killer Whales and Orcas Look Different?

False killer whales and orcas are both cetaceans, but they exhibit noticeable differences in appearance. Understanding these visual distinctions is straightforward when examining their size, coloration, and dorsal fins.


  • Orca males: Can reach up to 27 feet (8.2 meters) in length and can weigh up to 13,300 pounds (6.65 tons). The largest recorded individual measured 28 feet (8.5 meters) in length and weighed 16,500 pounds (about 8.25 tons).
  • Orca females: About 23 feet (7 meters) in length and weigh around 6,500 pounds (3.25 tons).
  • False killer whale males: Up to 20 feet (6 meters) in length and can weigh around 5,100 pounds (2.55 tons)
  • False killer whale females: Up to 16 feet (4.9 meters) in length and can weigh up to 2,600 pounds (1.3 tons)

So orcas are significantly larger than false killer whales.


  • Orca: Black body, white patches
  • False Killer Whale: Black or dark gray body, lighter underside

The classic orca has a distinctive black and white color pattern, with a stark white underside and eye patch contrasting with a black body. In contrast, false killer whales maintain a more uniform color, ranging from black to dark gray, and are slightly lighter on the underside.

Dorsal Fins and Features:

  • Orca: Tall, triangular dorsal fin
  • False Killer Whale: Sickle-shaped dorsal fin

The tall, triangular dorsal fin of an orca is an iconic shape that can be easily spotted against the horizon. On the other hand, false killer whales have a more curved, sickle-shaped dorsal fin.

False killer whales also have narrower and shorter flippers with a distinctive bulge on the leading edge, contrasting with the rounder paddles of the orca.

Distinctive markings further differentiate these species. Orcas typically feature a grey or white saddle patch just behind the dorsal fin, whereas false killer whales lack such a prominent marking.

False Killer Whales and Orcas: Behavioral Differences

Hunting Strategies and Diet:

  • Orcas: They are apex predators. They often hunt in coordinated groups and have diverse diets, including fish, seals, and even large whales.
  • False Killer Whales: These animals have a less aggressive approach and focus on a wider variety of fish and squid. They do not exhibit the same level of predatory behavior towards larger marine mammals.

Social Interaction:

  • Orcas: They are highly social creatures, existing in complex family groups known as pods. Their societies are structured and may involve intricate relationships.
  • False Killer Whales: They are also social, but their social behavior is characterized by less rigid structures. They often display playful behavior and may form bonds with other cetacean species.

Vocalizations and Communication:

  • Orcas: Orcas have a diverse range of vocalizations used for communication, navigation, and hunting. Each pod has distinct dialects and acoustic traits.
  • False Killer Whales: These whales also use sound for communication; however, their vocalizations are different in structure and may not be as varied as those of the orca.

The nuances in the behavior between false killer whales and orcas are significant but share an underlying social complexity and reliance on vocalization for bonding and coordination within their pods. Both species exhibit intelligence and a capacity for complex interactions.

How Do False Killer Whales and Orcas Interact with Other Marine Life?

False killer whales, while mesopredators, engage with other species through myriad behaviors, including both competition and cooperation. It is known that they may form alliances with other dolphin species during hunting, suggesting a complex level of social interaction. On occasion, they’ve even been observed sharing their catch with humans in the wild.

Conversely, orcas hold the title of apex predators, and their interactions with marine life reflect their dominance in the oceanic hierarchy. They orchestrate highly organized hunts to capture prey, which can include fish, seals, and even large whales. The presence of orcas can significantly alter the behavior of prey species, who must adapt to avoid becoming the next meal.

In terms of interactions between the two species themselves, reports and observations such as those mentioned in A review of Killer Whale interactions suggest encounters that range from indifference to direct competition. These interactions, however, are not fully understood and are a subject of ongoing research.

Their respective positions as top predators mean that both false killer whales and orcas influence the populations of their prey, which can cascade through the ecosystem. They also compete with other predators for the same food sources, playing a critical role in maintaining the natural balance of marine life populations.

What Threats Do False Killer Whales and Orcas Face?

Human Impact:

  • Pollution: False killer whales suffer from ocean pollutants like chemicals and plastics that contaminate their habitats.
  • Fishing: False killer whales face dangers such as entanglement in fishing gear and competition for food resources from fishermen.
  • Marine Traffic: Increased boat traffic can lead to distress and collisions, disrupting the normal behavior of both false killer whales and orcas.

Climate Change:

Conservation Status:


  • Research: Scientists are studying the behavior and migration patterns of false killer whales to mitigate threats.
  • Legislation: Laws such as the Marine Mammal Protection Act (MMPA) offer legal safeguards.
  • Public Awareness: Education and outreach inform the public about the importance of false killer whales and the challenges they face.

By addressing these threats and supporting conservation initiatives, we can help secure a future for both false killer whales and orcas.

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