逆戟鯨或虎鯨具有世界性分布，并且已經(jīng)記錄或建議了幾個(gè)不同的種群或類型。三到五種類型的逆戟鯨可能截然不同，足以被視為不同的種族、亞種，甚至可能是物種（參見物種問題）。IUCN在 2008年報(bào)告說，“該屬的分類學(xué)顯然需要重新審視，很可能O. orca將在未來幾年內(nèi)分裂成許多不同的物種或至少是亞種?！北M管不同虎鯨群的生態(tài)獨(dú)特性存在很大差異，這使得簡單的類型區(qū)分變得復(fù)雜。長期以來，人們認(rèn)為不同地區(qū)的食哺乳動物虎鯨可能是密切相關(guān)，但基因檢測駁斥了這一假設(shè)。
北部海域
北太平洋
1970年代和 80年代加拿大和美國西海岸的研究確定了以下三種類型：
駐留（食魚）逆戟鯨：彎曲的背鰭是駐留雌性的典型特征。
居民：這些是東北太平洋沿岸水域中最常見的三種種群。居民的飲食主要包括魚類，有時(shí)還包括魷魚，他們生活在稱為豆莢的復(fù)雜而有凝聚力的家庭群體中。女性居民的特征是具有圓形的背鰭尖端，終止于尖角。他們始終訪問相同的區(qū)域。不列顛哥倫比亞省和華盛頓常駐種群是世界上研究最深入的海洋哺乳動物之一。常駐虎鯨可分為至少三個(gè)不同的社區(qū)；阿拉斯加北部、南部和南部.阿拉斯加南部常駐虎鯨分布于阿拉斯加?xùn)|南部至科迪亞克群島，數(shù)量超過 700只。這些鯨魚由兩個(gè)雜交氏族組成，它們以聲音叫聲區(qū)分，并且它們的活動范圍重疊。北部居民社區(qū)居住在從阿拉斯加?xùn)|南部到溫哥華島的沿海和內(nèi)陸水域。它由三個(gè)部族和16個(gè)群組成，共有 300多頭逆戟鯨。南部居民社區(qū)通常棲息在不列顛哥倫比亞省南部和華盛頓的內(nèi)陸水域，但也可以在溫哥華島、華盛頓、俄勒岡和加利福尼亞的外海發(fā)現(xiàn)。它們由一個(gè)氏族和三個(gè)豆莢組成，數(shù)量不到 80只，被列為瀕危物種。
Transient or Bigg's：這些逆戟鯨的飲食幾乎完全由海洋哺乳動物組成.他們和居民住在同一地區(qū)，但兩人互相避開。暫住者通常以小團(tuán)體形式旅行，通常由兩到六只動物組成，并且與居民相比，它們的家庭紐帶不那么牢固。瞬變以較少變化和不太復(fù)雜的方言發(fā)聲。與居民相比，雌性瞬變的特征是更多的三角形和尖背鰭。背鰭周圍的灰色或白色區(qū)域，被稱為“馬鞍斑”，在居民身上通常含有一些黑色。然而，瞬變的馬鞍斑塊是實(shí)心的且均勻的灰色。瞬變沿海岸廣泛漫游；在阿拉斯加南部和加利福尼亞州都發(fā)現(xiàn)了一些個(gè)體。瞬態(tài)也被稱為Bigg's orca以紀(jì)念鯨魚學(xué)家 Michael Bigg.該術(shù)語已變得越來越普遍，并可能最終取代瞬態(tài)標(biāo)簽。據(jù)估計(jì)，瞬態(tài)生態(tài)型在 70萬年前就已經(jīng)分化。北美至少有三種不同的瞬變“種群”，即從威廉王子灣到基奈峽灣的 AT1種群、阿拉斯加灣/阿留申群島/白令海(GOA/AI/BS)種群和西海岸種群范圍從阿拉斯加?xùn)|南部到加利福尼亞。AT1被認(rèn)為是耗盡的庫存；它受到?？松郀柕掀澨柭┯褪录挠绊懖⒃?1989年至 2004年間從 22只減少到 8只。GOA/AI/BS的鯨魚數(shù)量可能約為 500頭，而西海岸的瞬態(tài)逆戟鯨數(shù)量超過 320頭，阿拉斯加?xùn)|南部、不列顛哥倫比亞省和華盛頓有 200多頭，加利福尼亞州外有 100多頭逆戟鯨.加利福尼亞的瞬變似乎與那些更遠(yuǎn)的北部和西海岸的瞬變混合得不多，可能會被劃分為子社區(qū)。
近海：1988年，一名座頭鯨研究人員在開闊水域觀察到它們時(shí)，在東北太平洋發(fā)現(xiàn)了第三個(gè)虎鯨種群。顧名思義，它們遠(yuǎn)離海岸，主要以成群的魚為食。然而，由于它們的背鰭很大，有傷痕和缺口，類似于捕獵哺乳動物的瞬態(tài)背鰭，因此它們可能也吃哺乳動物和鯊魚。它們大多在溫哥華島西海岸和海達(dá)瓜伊附近遇到.近海通常以 20-75只為一組聚集，偶爾會看到多達(dá) 200只的更大群體。人們對它們的習(xí)性知之甚少，但它們在基因上與居民和暫住者截然不同。Offshores似乎比其他的小，雌性的特征是背鰭尖端連續(xù)圓形。
在俄羅斯遠(yuǎn)東地區(qū)和日本北海道的沿海地區(qū)也存在獨(dú)立的食魚和食哺乳動物虎鯨群落。俄羅斯虎鯨常見于堪察加半島和指揮官群島周圍。在俄羅斯海域發(fā)現(xiàn)了超過 2，000只類似居民的虎鯨和 130只類似暫住的虎鯨。在熱帶太平洋東部，至少有 195只虎鯨被編目，范圍從北部的下加利福尼亞州和加利福尼亞灣到南部的南美洲西北海岸和西部的夏威夷。逆戟鯨似乎經(jīng)常出現(xiàn)在加拉帕戈斯群島附近.在夏威夷海域發(fā)現(xiàn)的逆戟鯨可能屬于太平洋中部的一個(gè)更大的種群。
北大西洋及鄰近地區(qū)
虎鯨在挪威Vestfjorden拍尾巴
據(jù)估計(jì)，北大西洋至少棲息著 15，000頭鯨魚。在東北大西洋，已經(jīng)提出了兩種逆戟鯨生態(tài)型。1型逆戟鯨由七種單倍型組成，包括挪威和冰島的以鯡魚為食的逆戟鯨和北海以鯖魚為食的逆戟鯨，以及挪威以外的以海豹為食的逆戟鯨。2型逆戟鯨由兩種單倍型組成，主要以須鯨為食。
在地中海，逆戟鯨被認(rèn)為是“訪客”，很可能來自北大西洋，而且越往東，虎鯨的蹤跡就越少。然而，直布羅陀海峽全年都有少量種群，2011年約有 39只。熱帶非洲西海岸也可能存在不同的種群，它們的飲食普遍。
大西洋西北部的種群全年都在拉布拉多和紐芬蘭周圍發(fā)現(xiàn)，而當(dāng)冰融化時(shí)，一些個(gè)體會季節(jié)性地前往加拿大東部北極地區(qū)的水域。南至科德角和長島都有目擊到這些鯨魚的記錄。這個(gè)種群可能與在格陵蘭島附近看到的逆戟鯨是連續(xù)的。全年都可以在加勒比?？吹交ⅥL，據(jù)估計(jì)，墨西哥灣北部有 267頭虎鯨（截至 2020年）。
北印度洋
印度洋北部已對 50多頭鯨魚個(gè)體進(jìn)行了編目，其中包括2008年在波斯灣和2015年在斯里蘭卡附近發(fā)現(xiàn)的兩只鯨魚。
南部海域
逆戟鯨擱淺在瓦爾德斯半島捕捉海獅
一小群逆戟鯨季節(jié)性地造訪阿根廷東海岸瓦爾德斯半島的北端，在岸邊捕食海獅和象海豹，暫時(shí)擱淺自己。在南非外海，存在一種獨(dú)特的“扁平牙齒”形態(tài)類型，它捕食鯊魚。一對雄性逆戟鯨Port和 Starboard因在南非海岸捕獵大白鯊和其他鯊魚而聞名。
虎鯨遍布澳大利亞、新西蘭和巴布亞新幾內(nèi)亞的水域。它們?nèi)甓荚谛挛魈m水域被發(fā)現(xiàn)，而在澳大利亞附近，它們季節(jié)性地集中在西北部的寧格魯礁近岸水域和西南部的布雷默地區(qū)。遺傳證據(jù)表明，新西蘭、澳大利亞西北部和西南部的虎鯨形成了三個(gè)不同的種群。新西蘭逆戟鯨主要捕食鯊魚和鰩魚。
南極
據(jù)估計(jì)，南極周圍大約有 25，000只逆戟鯨，有四種類型被記錄在案。蘇聯(lián)研究人員在 1980年代描述了兩個(gè)矮小物種，名為Orcinus nanus和Orcinus glacialis，但大多數(shù)鯨類研究人員對它們的地位持懷疑態(tài)度，并且很難將它們與下述類型直接聯(lián)系起來。
逆戟鯨變異的一些例子
A型或南極逆戟鯨看起來像“典型”逆戟鯨，體型龐大，黑白相間，眼罩中等大小，生活在開闊水域，主要以小須鯨為食。
B1型或浮冰虎鯨比 A型小。它有一個(gè)大的白色眼罩。它身體的大部分深色部分是中灰色而不是黑色，盡管它有一塊深灰色斑塊，稱為“背角”，從前額一直延伸到背鰭的后面。白色區(qū)域染成淡黃色。它主要以海豹為食。B1型逆戟鯨在阿德萊德島和南極半島大陸之間大量存在。
B2型或Gerlache逆戟鯨在形態(tài)上與 B1型相似，但更小。這種生態(tài)型已被記錄為以企鵝和海豹為食，并且經(jīng)常在Gerlache海峽發(fā)現(xiàn)。
C型或羅斯?；ⅥL是最小的生態(tài)型，并且比其他虎鯨生活在更大的群體中。它的眼罩明顯向前傾斜，而不是平行于身體軸線。和 B型一樣，它主要是白色和中灰色，有深灰色的背披和黃色斑塊。它唯一觀察到的獵物是南極鱈魚。
根據(jù) 1955年在新西蘭大規(guī)模擱淺的照片以及自 2004年以來的六次海上目擊事件， D型或亞南極逆戟鯨首次被識別出來。這種類型的第一個(gè)視頻記錄是在 2014年在凱爾蓋朗群島和克羅澤群島之間拍攝的，并且再次2017年在智利合恩角海岸外。它可以通過白色的小眼罩、比通常的背鰭更窄更短、球狀頭部（類似于領(lǐng)航鯨）和更小的牙齒來識別。它的地理范圍似乎在南緯40°S和60°S之間的亞南極海域環(huán)繞全球.雖然它的飲食尚未確定，但根據(jù)延繩釣船只周圍的照片確定，它可能包括魚類，其中 D型逆戟鯨似乎正在捕食巴塔哥尼亞齒魚( Dissostichus eleginoides )。
B型和 C型生活在靠近冰的地方，這些水域中的硅藻可能是這兩種類型的淡黃色的原因。線粒體 DNA序列支持這些是最近分化的獨(dú)立物種的理論。最近，完整的線粒體測序表明 B型和 C型被認(rèn)為是不同的物種，北太平洋的瞬變物種也應(yīng)如此，而將其他物種作為亞種等待更多數(shù)據(jù)。對整個(gè)線粒體基因組進(jìn)行測序的先進(jìn)方法揭示了不同人群之間 DNA的系統(tǒng)差異。2019年對 D型虎鯨的一項(xiàng)研究還發(fā)現(xiàn)，它們與其他種群不同，甚至可能是一個(gè)獨(dú)特的物種。
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 complicate 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.
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 commonly 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 complex 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 communities; 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 community 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 community 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.
Transient or Bigg's: The diets of these orcas consist almost exclusively of marine mammals. They live in the same areas as residents， but the two avoid each other. Transients generally travel in small groups， usually of two to six animals， and have less persistent family bonds than residents. Transients vocalize in less variable and less complex dialects. Female transients are characterized by more triangular and pointed dorsal fins than those of residents. The grey or white area around the dorsal fin， known as the “saddle patch“， often contains some black colouring in residents. However， the saddle patches of transients are solid and uniformly grey. Transients roam widely along the coast; some individuals have been sighted in both southern Alaska and California. Transients are also referred to as Bigg's orca in honour of cetologist Michael Bigg. The term has become increasingly common and may eventually replace the transient label. The transient ecotype is estimated to have diverged 700，000 years ago. There are at least three different “stocks“ of transients off North America， the AT1 stock which occurs from Prince William Sound to Kenai Fjords， the Gulf of Alaska/Aleutian Islands/Bering Sea (GOA/AI/BS) stock and the west coast stock which ranges from southeast Alaska to California. AT1 is considered a depleted stock; it was affected by the Exxon Valdez oil spill and declined from 22 individuals to eight between 1989 and 2004. The GOA/AI/BS stock may number around 500 whales while the west coast transients number over 320 orcas with over 200 along southeast Alaska， British Columbia and Washington and over 100 orcas off California. California transients do not appear to intermingle much with those further north and west coast transients may be divided into sub-communities.
Offshore: A third population of orcas in the northeast Pacific was discovered in 1988， when a humpback whale researcher observed them in open water. As their name suggests， they travel far from shore and feed primarily on schooling fish. However， because they have large， scarred and nicked dorsal fins resembling those of mammal-hunting transients， it may be that they also eat mammals and sharks. They have mostly been encountered off the west coast of Vancouver Island and near Haida Gwaii. Offshores typically congregate in groups of 20–75， with occasional sightings of larger groups of up to 200. Little is known about their habits， but they are genetically distinct from residents and transients. Offshores appear to be smaller than the others， and females are characterized by dorsal fin tips that are continuously rounded.
Separate fish-eating and mammal-eating orca communities also exist off the coast of the Russian Far East and Hokkaido， Japan. Russian orcas are commonly seen around the Kamchatka Peninsula and Commander Islands. Over 2，000 individual resident-like orcas and 130 transient-like orcas have been identified off Russia. At least 195 individual orcas have been cataloged in the eastern tropical Pacific， ranging from Baja California and the Gulf of California in the north to the northwest coast of South America in the south and west towards Hawaii. Orcas appear to regularly occur off the Galápagos Islands. Orcas sighted in Hawaiian waters may belong to a greater population in the central Pacific.
North Atlantic and adjacent
Orca tail-slapping in Vestfjorden， Norway
At least 15，000 whales are estimated to inhabit the North Atlantic. In the Northeast Atlantic， two orca ecotypes have been proposed. Type 1 orcas consist of seven haplotypes and include herring-eating orcas of Norway and Iceland and mackerel-eating orcas of the North Sea， as well as seal-eating orcas off Norway. Type 2 orcas consist of two haplotypes， and mainly feed on baleen whales.
In the Mediterranean Sea， orcas are considered “visitors“， likely from the North Atlantic， and sightings become less frequent further east. However， a small year-round population exists in the Strait of Gibraltar， which numbered around 39 in 2011. Distinct populations may also exist off the west coast of tropical Africa， which have generalized diets.
The northwest Atlantic population is found year-round around Labrador and Newfoundland， while some individuals seasonally travel to the waters of the eastern Canadian Arctic when the ice has melted. Sightings of these whales have been documented as far south as Cape Cod and Long Island. This population is possibly continuous with orcas sighted off Greenland. Orcas are sighted year-round in the Caribbean Sea， and an estimated 267 (as of 2020) is documented in the northern Gulf of Mexico.
North Indian Ocean
Over 50 individual whales have been cataloged in the northern Indian Ocean， including two individuals that were sighted in the Persian Gulf in 2008 and off Sri Lanka in 2015.
Southern waters
Orca beaching to capture sea lion at Valdes Peninsula
A small population of orcas seasonally visits the northern point of the Valdes Peninsula on the east coast of Argentina and hunt for sea lions and elephant seals on the shore， temporary stranding themselves. Off South Africa， a distinctive “flat-tooth“ morphotype exists and preys on sharks. A pair of male orcas， Port and Starboard， have become well known for hunting great whites and other sharks off the South African coast.
Orcas occur throughout the waters of Australia， New Zealand and Papua New Guinea. They are sighted year round in New Zealand waters， while off Australia， they are seasonally concentrated off the northwest， in the inshore waters of Ningaloo Reef， and the southwest， at the Bremer region. Genetic evidence shows that the orcas of New Zealand， and northwest and southwest Australia form three distinct populations. New Zealand orcas mainly prey on sharks and rays.
Antarctic
Around 25，000 orcas are estimated around the Antarctic， and four types have been documented. Two dwarf species， named Orcinus nanus and Orcinus glacialis， were described during the 1980s by Soviet researchers， but most cetacean researchers are skeptical about their status， and linking these directly to the types described below is difficult.
Some examples of variations in orcas
Type A or Antarctic orcas look like a “typical“ orca， a large， black-and-white form with a medium-sized white eye patch， living in open water and feeding mostly on minke whales.
Type B1 or pack ice orcas are smaller than type A. It has a large white eye patch. Most of the dark parts of its body are medium grey instead of black， although it has a dark grey patch called a “dorsal cape“ stretching back from its forehead to just behind its dorsal fin. The white areas are stained slightly yellow. It feeds mostly on seals. Type B1 orca are abundant between Adelaide Island and the mainland Antarctic peninsula.
Type B2 or Gerlache orcas are morphologically similar to Type B1， but smaller. This ecotype has been recorded feeding on penguins and seals， and is often found in the Gerlache Strait.
Type C or Ross Sea orcas are the smallest ecotype and live in larger groups than the others. Its eye patch is distinctively slanted forwards， rather than parallel to the body axis. Like type B， it is primarily white and medium grey， with a dark grey dorsal cape and yellow-tinged patches. Its only observed prey is the Antarctic cod.
Type D or Sub-Antarctic orcas were first identified based on photographs of a 1955 mass stranding in New Zealand and six at-sea sightings since 2004. The first video record of this type was made in 2014 between the Kerguelen and Crozet Islands， and again in 2017 off the coast of Cape Horn， Chile. It is recognizable by its small white eye patch， narrower and shorter than usual dorsal fin， bulbous head (similar to a pilot whale)， and smaller teeth. Its geographic range appears to be circumglobal in sub-Antarctic waters between latitudes 40°S and 60°S. Although its diet is not determined， it likely includes fish， as determined by photographs around longline vessels， where Type D orcas appeared to be preying on Patagonian toothfish (Dissostichus eleginoides).
Types B and C live close to the ice， and diatoms in these waters may be responsible for the yellowish colouring of both types. Mitochondrial DNA sequences support the theory that these are recently diverged separate species. More recently， complete mitochondrial sequencing indicates the types B and C be recognized as distinct species， as should the North Pacific transients， leaving the others as subspecies pending additional data. Advanced methods that sequenced the entire mitochondrial genome revealed systematic differences in DNA between different populations. A 2019 study of Type D orcas also found them to be distinct from other populations and possibly even a unique species.