The Biggest Dolphin
The orca, also known as the "killer whale” is the largest member of the dolphin family. Orcas are found in all the world’s oceans, both in coastal waters and the open sea, but they generally prefer cooler water. Orcas have long, rounded bodies with large dorsal fins at the middle of their backs. Their black bodies are marked with white patches on the underside and near the eyes. Orcas are highly social animals that travel in groups called pods. Pods usually consist of 5 to 30 whales, although some pods may combine to form a group of 100 or more. Orcas are able to control the flow of blood to their hearts and brains, which keeps them from suffering from a lack of oxygen when they are deep underwater. They use sounds to communicate with each other, but each pod has its own unique 'accent,' which makes it easy for Orcas to identify members of their own pods.
Orcas can grow as long as 32 feet and can weigh as much as 22,000 pounds, which means that they are about as big as a school bus. They use echolocation - bouncing sound off of objects to determine their location - to hunt, and use a series of high-pitched clicks to stun prey. Orcas feed on fish, squid, birds, and marine mammals. They eat up to 5% of their body weight each day. This averages out to over 500 pounds of food for each Orca.
Orcas are among the most contaminated marine mammals in the world. Pollution and chemical contamination make them more susceptible to disease. Humans have long been fascinated by killer whales, but until recently very little was known about their lives at sea. They are animals shrouded in myth, and many times this misinformation has led to their destruction.