Orcas, also known as killer whales or blackfish, are the largest species of dolphin, growing to a maximum of 9.8 m long and 10,000 kg. They can swim at a maximum speed of 48 kilometres per hour and travel 120-160 km per day. They are a cosmopolitan species, living in all oceans of the world. Orcas are highly social creatures. They are one of few species that are known to exhibit culture, and one of fewer still with different cultural groups inhabiting the same geographic area without interacting with one another. Cultural groups of orcas differ in vocal dialect, social organization, behaviour, prey and hunting tactics. Some groups have not interbred with others for hundreds of thousands of years, and may actually be different species. There are several described ecotypes...