The dusky dolphin is limited to the south of the planet including the tip of the American continent, New Zealand and some southern islands.
Bottlenose dolphins have a broad distribution that includes most of the tropical, subtropical and temperate parts of the ocean where there are several kinds of habitats.
Dolphins are not frequent victims of any predator in the ocean due to their sociability and intelligence, but killer whales and some large sharks are their main natural threat.
Dolphins evolved from land animals that returned to the ocean due to environment conditions.
The False Killer Whale (Pseudorca crassidens) is the third largest dolphin in the world, although it does not have genetic relation with the orcas, it shares some morphological similarities.