When we think of the ocean’s top predators, most of us are probably going to picture sharks. More specifically, we’re probably picturing the massive great white shark.
But a couple weeks ago we shared an article about an interesting way to scare sharks away from Australia’s beaches: playing recordings of killer whale ‘screams’. If the great white shark is truly the ocean’s top predator, why would it be so scared of killer whales?
Well, it turns out that killer whales have been known to prey on sharks.
Orcas have also been known to eat mako sharks and several other species. When hunting sharks, killer whales always end up flipping the shark upside down, regardless of how the attack starts. When flipped upside down, the shark goes into a paralyzed state known as ‘tonic immobility’ and can’t fight back, which suggests that the orcas understand a little something about shark biology. It doesn’t necessarily mean they understand the process, just that they know if the shark is upside down, they won’t get hurt.
Before we get into some examples, here’s what you need to know about our competitors:
Killer Whale, Orcinus orca:
- Size: Males can reach lengths of 32 feet (9.6 m) and weigh up to 9 tons. Females can reach 23 feet (8.2 m) in length and weigh up to 4 tons.
- Speed: They usually swim at speeds of 3 to 4 miles (5 to 6.4 km) per hour but can reach speeds of up to 30 miles (48 km) per hour in short bursts.
- Diet: Killer whales have 40-50 large conical teeth (3 in / 7.6 cm) that they use to capture and tear prey, not to chew. Their diets differ in based on population. In the North Pacific, resident killer whales eat fish, primarily salmon, while transient killer whales prey on marine mammals. In New Zealand waters, killer whales have been known to feed on stingrays and sharks.
Hunting techniques: Killer whales are highly social animals and live in groups (pods) that range from 2 to 15 animals, but they have occasionally been seen hunting in groups of up to 40. Killer whales work together when hunting and they teach each other techniques. Mothers have been observed teaching their young how to beach themselves to hunt seals. In Antarctica, they make waves to wash seals off of floating ice, a behavior that isn’t seen anywhere else in the world.
Great White Shark, Carcharodon carcharias:
- Size: White sharks can reach lengths of more than 20 feet (6 m) and weigh more than 5,000 pounds (2,268 kg).
- Speed: They usually swim at speeds of around 15 miles (24 km) per hour.
- Diet: White sharks are the largest predatory fish in the world. Their razor-sharp, triangular teeth can measure more than 2.5 inches (5.7 cm) long and they use them to tear big chunks of flesh off their prey. They feed primarily on fish and actively hunt small marine mammals, including dolphins, seals and sea lions, but they also occasionally eat sea turtles, molluscs and crustaceans.
Hunting techniques: Generally they are solitary animals, swimming alone or with one other shark. Sometimes, usually when feasting on a carcass, groups of about 10 or more have been spotted. Their hunting techniques vary based on the prey. When hunting brown fur seals, they ambush the seal from below, hitting the seal at high speeds. They often ambush from above or below to avoid being seen, but many Altantic great whites will hunt close to shore in shallow waters. They have also been known to scavenge on whale carcasses.
Winner: The great white shark might have scarier teeth, but the killer whale is bigger and faster. Killer whales also have an advantage when hunting in big groups.
Notable examples of sharks vs. killer whales:
Blue Cliffs Beach, Tuatapere, New Zealand – Boxing Day 2011
A group of sharks had been swimming near the beach when a pod of orcas showed up. The orcas herded the sharks towards the shore, forcing them into shallower waters — one shark tried so hard to get away it actually beached itself. None of the beachgoers were sure if the orcas ended up getting a good meal, but they did notice some of the sharks were injured. You can see a video of it in this article.
Farallon Islands, off the coast of San Francisco, California – October 1997
A group of whale watchers was already enjoying a successful outing, having seen two orcas that had just killed a sea lion. They watched the orcas for a while longer when something much more interesting happened. A great white shark swam towards the boat (probably coming towards the smell of the dead sea lion) and then promptly switched directions when one of the orcas started swimming towards it. Both disappeared for a short time and then the orca resurfaced with the dead shark in its mouth.
Watch the following clip to learn more about this incident:
To learn more:
- Check out another cool clip of the Farallon Islands event.
- Check out this comparison of different killer whale populations.
- For an incredibly thorough analysis, watch this 50-minute video with Dr. Ingrid N. Visser: The Whale That Ate Jaws.
Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.