Thanks to Pranav for this week's topic, the orca or killer whale! Further reading: https://www.nationalgeographic.com/animals/2019/07/killer-whales-orcas-eat-great-white-sharks/ Save Our Seas Magazine (I took the Jaws art below from here too) An orca: Orcas got teeth: Starboard and Port amiright: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week let’s return to the sea for a topic suggested by Pranav, the orca. That’s the same animal that’s sometimes called the killer whale. While it is a cetacean, it’s more closely related to dolphins than whales and is actually considered a dolphin although it’s much bigger than other dolphin species. The orca grows up to 26 feet long, or 8 meters, and is mostly black with bright white patches. The male has a large dorsal fin that can be 6 feet tall, or 1.8 meters, while females have much shorter dorsal fins that tend to curve backwards more than males’ do. Some orcas have lighter coloring, gray instead of black or with gray patches within the black. The orca lives throughout the world’s oceans although it especially likes cold water. It eats fish, penguins and other birds, sea turtles, seals and sea lions, and pretty much anything else it can catch. Everything about the orca is designed for strength and predatory skill. It has good vision, hearing, sense of touch, and echolocation abilities. It’s also extremely social, living in pairs or groups and frequently hunting cooperatively. Some populations of orca live in the same area their whole lives, traveling along the same coastline as they hunt fish. These are called resident orcas and they’re closely studied since researchers can tell individuals apart by their unique markings, so can keep track of what individuals are doing. Other populations are called transient because they travel much more widely. Transient and resident orcas avoid each other, so they may be separate species or subspecies, although researchers haven’t determined whether this is the case yet. There’s even a newly discovered population of orcas found off the tip of South America that may be a new species. Researchers are analyzing DNA samples taken from the South American orcas with little darts. Fishers had reported seeing odd-looking small orcas in the area for over a decade, but recent photos taken by tourists gave researchers a better idea of what they were looking for. The new orcas have rounder heads and different spotting patterns than other orca populations. Transient orcas eat more mammals than resident orcas do. Resident orcas mostly eat fish. They have clever ways of catching certain fish, too. A pod of orcas can herd herring and some other fish species by releasing bubbles from their blowholes, which frighten the fish away. A group of orcas releasing bubbles in tandem can make the school of fish form a big ball for protection. Then each orca slaps the ball with its tail. This stuns or even kills some of the fish, which the orca then eats easily. Pretty clever. An orca may also stun larger fish by smacking it with its powerful tail flukes. But the orca is also good at catching seals and sea lions. Some orcas learn to beach themselves safely when chasing seals, since the seal will often try to escape onto land. Another hunting technique is called wave-hunting, where a group of orcas swim in a way that causes waves to slop over an ice floe. Any animal or bird resting on the ice floe is washed into the water. Because transient orcas mostly hunt mammals that can hear the orcas’ echolocation clicks and other vocalizations, they tend to stay silent while hunting so they don’t alert their prey. Resident orcas don’t have to worry about noise as much, since most of the fish they eat either can’t hear or their calls or don’t react to them. Resident orcas are much more vocal than transient orcas as a result. But all orcas have calls they use socially.