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B型和 C型生活在靠近冰的地方，这些水域中的硅藻可能是这两种类型的淡黄色的原因。线粒体 DNA序列支持这些是最近分化的独立物种的理论。最近，完整的线粒体测序表明 B型和 C型被认为是不同的物种，北太平洋的瞬变物种也应如此，而将其他物种作为亚种等待更多数据。对整个线粒体基因组进行测序的先进方法揭示了不同人群之间 DNA的系统差异。2019年对 D型虎鲸的一项研究还发现，它们与其他种群不同，甚至可能是一个独特的物种。
英文原文：
Orcas or killer whales have a cosmopolitan distribution and several distinct populations or types have been documented or suggested. Three to five types of orcas may be distinct enough to be considered different races， subspecies， or possibly even species see Species problem. The IUCN reported in 2008，“The taxonomy of this genus is clearly in need of review， and it is likely that O. orca will be split into a number of different species or at least subspecies over the next few years.“ Although large variation in the ecological distinctiveness of different orca groups plicate simple differentiation into types. Mammal-eating orcas in different regions were long thought likely to be closely related， but genetic testing has refuted this hypothesis.
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Northern waters
North Pacific
Research off the west coast of Canada and the United States in the 1970s and 1980s identified the following three types:
Resident fish-eating orcas: The curved dorsal fins are typical of resident females.
Resident: These are the most monly sighted of the three populations in the coastal waters of the northeast Pacific. Residents' diets consist primarily of fish and sometimes squid， and they live in plex and cohesive family groups called pods. Female residents characteristically have rounded dorsal fin tips that terminate in a sharp corner. They visit the same areas consistently. British Columbia and Washington resident populations are amongst the most intensively studied marine mammals anywhere in the world. Resident orcas can be divided into at least three distinct munities; northern， southern and southern Alaskan. Southern Alaskan resident orcas are distributed from southeastern Alaska to the Kodiak Archipelago and number over 700 individuals. These whales consist of two interbreeding clans distinguished by acoustic calls and whose ranges overlap. The northern resident munity lives in coastal and inland waters from southeastern Alaska to Vancouver Island. It consists of three clans and 16 pods and number over 300 orcas total. The southern resident munity generally inhabits the inland waters of southern British Columbia and Washington， but can be found in the outer waters off Vancouver Island， Washington， Oregon and California. They consist of one clan and three pods， and number less than 80 individuals and are listed as endangered.
