Main Idea Definition:
The main idea is the most important point the author wants you to understand about a topic. It's like the "big picture" of what you're reading.
The central topic or theme of each section
Specific facts, examples, and evidence
The main idea is the most important point the author wants you to understand about a topic. It's like the "big picture" of what you're reading.
Supporting details are specific facts, examples, descriptions, or explanations that help prove or explain the main idea.
Herman Melville, the writer of the famous whale story Moby Dick, once wrote that humpback whales were "the most lighthearted1 of all the whales." A favorite of whale watchers everywhere, they often swim in ocean areas close to land and are active at the surface. They can often be seen breaching, or rising out of the water, and then coming down with a great splash. Humpbacks are intelligent animals, and can be seen working together to hunt schools of small fish. And, if you listen closely, you might even hear one singing.
1 Someone or something that is lighthearted is cheerful and happy.
Humpback whales are active, intelligent, and entertaining whales that can be easily observed by people.
Herman Melville called them "the most lighthearted of all the whales"
They are a favorite of whale watchers
They swim in ocean areas close to land
They are active at the surface (breaching, splashing)
They are intelligent and work together to hunt
They can be heard singing
Recording Gentle Giants
Marine biologist2 Jim Darling has studied the songs of humpback whales for more than 25 years. While recording whale songs on a boat near Hawaii, he invited author Douglas Chadwick to experience diving with a humpback. In the water, Chadwick heard the whale's songs in a way he had never heard them before. "Suddenly, I no longer heard the whale's voice in my ears," he said. "I felt it inside my head and bones."
2 A marine biologist is a scientist who studies ocean life.
Scientists study humpback whale songs by recording them underwater, providing unique experiences.
Jim Darling has studied humpback whale songs for more than 25 years
He was recording whale songs on a boat near Hawaii
He invited author Douglas Chadwick to experience diving with a humpback
Chadwick heard the whale's songs underwater in a completely new way
"I felt it inside my head and bones" - Chadwick's experience
Why Do They Sing?
Darling says that only male humpbacks sing, but for unknown reasons. One idea is that they sing to attract females. However, when a group of scientists played recordings of whale songs in the ocean, female whales did not respond. Another idea is that male humpbacks use their songs to let other males know they are in the area.
Researchers have also found that humpback whale songs are different in different parts of the world, perhaps like whale national anthems.5 They may also be like hit tunes on the radio, changing over time - from one year to the next, or even over a single breeding season.
5 A national anthem is a country's song, chosen to represent its people.
Scientists have theories about why male humpback whales sing, but the exact reason is still unknown.
Only male humpbacks sing, but for unknown reasons
One theory: they sing to attract females
When scientists played whale songs, female whales did not respond
Another theory: males use songs to communicate with other males
Humpback whale songs vary by location and change over time.
Songs are different in different parts of the world
Like "whale national anthems"
Songs change over time like "hit tunes on the radio"
Changes happen from year to year or within a breeding season
When swimming with the whale, Chadwick could see that it was aware of him, but not worried by his presence. The 13-meter-long giant looked him over3 curiously, but never harmed him. The whale then swam under the boat. It pointed its head down to the ocean floor and, with flippers4 extended out to its sides, began to sing. Up in the boat, Darling recorded the whale's song. Humpback whale songs can be long and complex, sometimes lasting for 30 minutes or more. They are perhaps the longest songs sung by any animal.
3 If you look something over, you examine it for a short period of time.
4 Flippers are the two flat body parts that stick out from the side of a whale, seal, etc.
Main Idea: The humpback whale behaved gently around Chadwick and demonstrated its complex singing behavior.