Studies have revealed that whales learn, teach, plan, cooperate, and grieve. There are 39 species of whales, divided into 2 parvorders—baleen whales, who have a sieve structure in their upper jaw that filters plankton for food, and toothed whales, who have sharp teeth for hunting.

Whales have been hunted by humans since the Stone Age. In the 20th century alone, humans killed 2.8 million whales and, as a result, wiped out 90% of all blue whales. Today, human-caused ocean pollution is killing countless whales. They ingest poisonous chemicals, and swallow plastic containers, sheeting, and bags which fill their stomachs causing starvation.

Of the 13 great whale species, 6 are in danger of extinction, even though they are at the top of the marine food chain. Today, whales are protected by international law; nonetheless, Japan, Norway, and Iceland continue to hunt whales, as do aboriginal groups in Canada, Siberia, and Alaska.

Blue whales are the largest animal to ever live on Earth, reaching over 100 feet in length and weighing at least 350,000 pounds.