Cetaceans

List of cetaceans
Mainly, cetaceans are marine mammals that had evolved from land mammals.

Evolution
They evolved from land mammals, they lost their back legs. Their front legs turned to flippers. As well, whales have grown larger.

Types
Three types of marine mammals are here; whales, dolphins, and porpoises. In the infraorder cetaceans, there are two parvorders, toothed whales and baleen whales. Dolphins, porpoises, beluga whales, narwhals, and sperm whales are toothed whales. The rest are baleen whales with an amount of 1/10 of all cetaceans.

Trivia

 * Whales are not large fish and have lungs.
 * Whales hold their breath for possible as 2 hours.
 * Dolphins hold their breath for 20 minutes.
 * Orcas and pilot whales are actually dolphins.
 * Hector's dolphin is the smallest cetacean discovered at 4 feet (1 m) long and 110 lbs (0.055 tons).
 * The blue whale is the largest animal on Earth found at 100 feet (30 m) long and 300,000 lbs (150 tons).
 * Cuiver's beaked whale dives to 10,000 feet (3,048 m) deep. That is almost two miles.