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All Creatures,

Episode 97: Orca Culture & Behavior, Part II

June 11, 2019

This week is a continuation of our Episode 95: Awed by Orcas. Here we go into more detail on the concept that Orcas have developed culture. We also go into depth of the different hunting behaviors of the various ecotypes of Orcas.

Orca Physiology

We started off discussing echolocation. A very surprising fact for us was that sound travels faster through water than air.

Orcas, which technically are dolphins and ‘whales’, as we discussed in the previous episode. Just like dolphins they use echolocation to navigate and hunt food. Orcas generate sound waves in the dorsal bursa, which go through the front portion of their forehead, called the melon. This helps direct the sound. When the sound wave bounces back, which feeds through their jaw and into their ear.

Orcas diet is going to vary wildly depending on their ecotype. We covered this in Part I and talked about what each ecotype specializes in. They eat fish, other oceanic mammals, and even birds.

Orca Behavior

Four killer whales swim in McMurdo Sound. Researchers from NOAA Fisheries, Southwest Fisheries Science Center are studying the whales to determine if there are three separate species of Antarctic killer whales. They took aerial photos of the whales, such as this one taken in January 2005, as part of their work.

The major focus of this episode is Orca behavior. We started off with hunting strategies.

  • Wave washing technique. An Orca pod coordinates as a group to swim towards a seal or other prey item on a ice float. As they near the prey they dive and use their tails, all coordinated, to develop a wave, thus washing
  • Karate chop technique. Orcas use this technique with sharks, more specifically, great white sharks. Will use tail to create a vortex under the shark forcing it to the surface. When near the surface, they will slap the sharks head with its tail. The Orca then turn the shark over, putting the shark in tonic immobility.
  • Carousel technique. This is used by Orcas to tighten up schools of fish. Orcas will use belly flashes and bubbles to push the fish into a tight circle, so the whales can grab and eat the fish easier.
  • Pod Pin technique. Here the Orca will push narwhals into shallower waters, herding them, and once trapped, will begin to kill and eat the narwhales. This is especially concerning because narwhals historically have been able to hide from Orcas in the Arctic sea ice. With less sea ice, the narwhal has no where to hide.
  • Blowhole block technique. When hunting larger whales, Orcas will at times jump onto the larger whale to try and prevent it from taking a breath.
  • D Day technique. Here Orcas will purposely beach themselves to grab a seal pup and then wait for an ensuing wave to splash and pull themselves back into the ocean.

One of the most insightful articles we read about Orcas is HERE. This argues that Orcas have developed culture.

Looking at what “culture” actually means, helps to better understand these animals. The one definition that defines it fits rather nicely to the Orca. It states:

Culture in its broadest sense is cultivated behavior; that is the totality of a person’s learned, accumulated experience which is socially transmitted, or more briefly, behavior through social learning.

Orcas are an incredibly socially adapt mammal, much like primates. There is a lot of scientific evidence that Orcas pass on learned skills to their offspring. They even undertake what is called “apprenticeships” in which they specifically train a specific Orca.

Orcas also have very tight family groups and their older members, mainly their grandmothers, play critical roles in Orca society. Another article HERE discusses it again.

Orca Conservation

The IUCN currently has Orca listed as data deficient. This means that, despite being studied, there is still not enough information about total populations to make a definitive analysis. The closest estimate we have of Orca total population is above 50,000 total animals on Earth. However, we also did discuss that certain groups or ecotypes, specifically the Southern Resident Orca population off the Pacific Northwest.

Organizations to Support

Center for Whale Research

 

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