What is an Orca?
Orcas are also known as Killer Whales. It is a marine mammal or sea mammal. Orcas are the largest member of the dolphin family. Whales and dolphins are cetaceans. There are about 90 species of cetaceans broken up into two groups.
Why is an orca called a Killer Whale?
Orcas do not attack people, but they are at the top of the food chain. It is believed they’re called killer whales because they are able to attack vicious animals such as sharks. They also attack large animals such as whales. Orcas have even been known to jump onto the ice to grab and attack a bird or other animals before getting back into the water.
Types of Orcas
There’s still a lot to learn about orcas. For a long time, scientists believed that there were 1 species of orca. Now scientists believe that orcas can be split into 3 different groups based on size, diet, and migration:
- Resident Orcas: Resident orcas are orcas that spend most of their time living in one area. They may travel for food, but they do not go too far. Resident orcas stay closer to the coast, within 500 miles from the shore. They live in areas where the water is 650ft. They live in groups called pods.
- Transient Orcas: Transient orcas are orcas that don’t stay in one place for too long. They travel further for food. Like Resident Orcas, Transient Orcas stay with 500 miles from shore and live in areas where the water is around 650ft deep. They also live in groups called pods.
- Off-Shore Orcas: Little is known about offshore orcas. They prefer deeper waters. They do not come close to the shore often. Offshore Orcas migrate thousands of miles and live in larger groups called pods.
What is a Marine Mammal?
Mammals are animals that have a backbone, fur or hair, use lungs to breathe and give birth to live babies that drink milk from their mothers after they are born.
Marine Mammals are mammals that live in the water and get their food from the water.
There are four main groups of marine mammals
- Whales and dolphins
- Seals, sea lions, and walruses
- Manatees and dugong
- Sea otters and polar bear
What Does an Orca Look Like?
Moving through the water is a lot harder than walking on land. Orcas have large torpedo-shaped black bodies with white bellies that help them push through the water. Underneath their tails is also white and they have a white patch above their eye.
Males are larger than females. They are around 30 ft long and weigh 10 tons. A large male is bigger than an elephant. Females are around 26 ft and weigh in at 9 tons.
Males may be larger than females, but females live longer. In the wild male orcas usually live around 60 years and females live up to 90 years.
Orcas have a strong tail with two flat panels called a fluke. Their horizontal flukes move up and down to help them move across the water. Much small fish have vertical tails that move side to side to help them move forward through the water. An orca’s fluke has no bones and is curved at the end.
Dorsal Fin
Orcas have a dorsal fin on its back to help them stay balanced in the water. A male’s dorsal fin can be 6 ft tall and is shaped like a triangle. Young orcas and females have smaller dorsal fins that are curved.
Pectoral Fin
An orcas pectoral fins are also called flippers. They have one flipper on each side of its body. Pectoral fins help the orca steer through the water.
Orca’s fins have an important job. They help control the orca’s body temperature. When an orca swims fast through the water it gets hot. The heat escapes the orca’s body through the dorsal fin, pectoral fin, and tail.
Blubber
Orcas have a thick layer of fat below its skin called blubber. It is 3-4 inches thick. Their Blubber is what keeps the orca warm while swimming in cold waters. Their blubber also stores food and helps the orca float.
Jaw and teeth
Orcas have strong powerful jaws. They have 40-56 sharp, curved teeth, that are 3-4 inches long. Their strong jaw allows them to rip off chunks of food and swallow it whole. They do not chew their food.
Blowhole
Orcas have a blowhole on top of their head. When an orca comes to the surface for air, their blowhole opens to allow air in. When they dive down into the water their blowhole closes so that water does not get in.
Orcas can hold their breath underwater for 12 mins.
Orca Traits
Orcas can be very fast swimmers, just as fast as sharks. Orcas can swim up to 30 mph. That is faster than you can run! Most of the time orcas take it slow and do not swim at that speed.
Orcas have great eyesight, but no sense of smell. Orcas also have great hearing. They can hear better than humans.
Echolocation
Orcas use something called echolocation. Echolocation is a way that some animals find things around them through the use of sound. Orcas have a special body part located in their forehead called melon. The melon sends out the clicking sounds and whistles. The sounds travel through the water until they hit an object in the water. The sound will bounce off the object and back to the orca so it knows its there.
Dolphins, Bats, and other tooth whales used echolocation.
Where do Orcas Live?
A habitat is where an animal lives. Orcas can be found all over the world in all 7 oceans:
Arctic
North Atlantic
South Atlantic
Indian
North Pacific
South Pacific
Southern
Orcas have been spotted in tropical waters in areas such as Hawaii and Australia, however, they prefer cooler water in the North. They can be found regularly around Iceland, Norway, Alaska, Antarctica, and Scotland.
What do Orcas Eat?
Orcas are carnivores, meaning that they eat meat. Many orcas will migrate to search for food. Adult orcas eat 3-4% of their body weight daily, young orcas will eat up to 10% of their body weight daily.
Orcas eat herring, salmon, seals, sea birds, dolphins, sea lions, penguins, stingrays, sharks, and some whales
Orcas hunt in groups. They circle around their prey and then will attack.
Are Orcas Social Animals?
Yes, like dolphins orcas are social. They live in groups called pods. Pods can have a small number of orcas of 5-10 and some have over 50 members.
Orcas use a variety of clicks, whistles, and calls to communicate with other orcas.
Orca Behaviors
Orcas can be jumping out of the water and landing on their backs, this is known as breaching. They will perform fluke slapping. This is when orcas slap their tails on the surface of the water. Orcas will often pop their heads out of the water to check out what is going on, this is known as skyhopping.
What is a Baby Orca Called?
Female orcas are called cows, males are called bulls. A baby orca is called a calf. A calf is born underwater close to the surface. Calves are 8ft long when they are born. They weigh nearly 400 pounds. Calves drink milk from their moms. At around 4 months they will start eating food. Calves eat 10% of their body weight every day.
In one year the calf will grow to be 10ft and weight 1,000 pounds. Calves stay with their mothers for 1-2 years.
Predators
Orcas are at the top of the food chain. They are not hunted by any other animals in the sea. The only predator to an orca is humans. In some countries around the world sometimes orcas are hunted by fishermen. They are sometimes hunted for food and other times to protect the fish population in the area.
Are Orcas an Endangered Species?
The world’s population of orcas is unknown, so scientists cannot determine their conservation status. In 1972 Dr. Michael Biggs researched orcas. He found a new way to track orcas. He realized that dorsal fins on the animal were slightly different on each orca. Scientists now use photo identification to count and track orcas in a specific area. Even with that new find, scientists still aren’t able to find and track all orcas.
Famous Orcas
Shamu: Sea World parks had a Shamu show. The show featured an orca named Shamu that performed different tricks. Different orcas actually played Shamu throughout the years. Sea World has since stopped breeding orcas from backlash stating the animals were mistreated.
Willy: Willy was an orca from the 1993 movie Free Willy. In the movie, Willy lives and performs at an amusement park where a 12-year-old boy Jesse is doing community service. Jesse becomes friendly with Willy. He realizes that Willy is very unhappy in captivity. He works with Willy’s trainer to set him free. The movie ends with Willy being set free. Michael Jackson wrote the hit song to the movie “Will You Be There” Keiko was the real name of the orca who played Willy. Keiko was also freed into the wild after handlers worked with him to help him adapt. Keiko had trouble adapting to the wild later died of pneumonia.
References:
Killer Whales by Leo Statts
Killer Whales by Seymour Simon
Orcas by Claire Throp