According to Wikipedia:
The Orca or Killer Whale (Orcinus orca) is the largest species of the oceanic dolphin family (Delphinidae). It is found in all the world's oceans, from the frigid Arctic and Antarctic regions to warm, tropical seas. Orcas are highly social and generally travel in stable, matrilineal family groups.
They are versatile predators with some populations feeding mostly on fish and others on marine mammals, including sea lions, seals, and large whales. Wild Orcas are usually not considered a threat to humans. There have, however, been isolated reports of captive Orcas attacking their handlers at marine theme parks.
The Humpback Whale, Megaptera novaeangliae, is a mammal which belongs to the baleen whale suborder. The Humpback is a very large whale: an adult can usually range between 12–16 m (40–50 ft) long and weighs approximately 36,000 kg (79,000 pounds), or 36 tonnes (40 short tons); females, on average, are larger than males. It is well known for its breaching (leaping out of the water), its unusually long front fins, and its complex whale song. The Humpback Whale lives in oceans and seas around the world, and is regularly sought out by whale-watchers.
The Beluga Whale or White Whale (Delphinapterus leucas) is an Arctic and sub-arctic species of cetacean. This marine mammal is commonly referred to simply as the Beluga - the word derives from the Russian word for white.
This large whale can be up to 5m (16 ft) long, larger than all but the largest dolphins but smaller than most other toothed whales. Males are generally larger than the female - males can weigh 1.5 tons and females about one ton.