False Killer Whale (범고래붙이)

 

범고래붙이, 흑범고래(Pseudorca crassidens)

영명 : False Killer Whale

 

몸길이 : 4.4~5.2m, 몸무게 : 1~2t. 흑범고래 라고도 한다. 가슴지느러미 앞쪽 가장자리의 가운데 부분이 부풀어 있다.

몸은 길고 가는 편이며 흑색이다. 머리는 작고 돌출된 둥근 모양이다. 입 언저리는 머리 부분 뒤쪽까지 연장되어 있다. 입술은 흰색이다. 가슴지느러미는 작고 전반부가 혹처럼 둘러져 있고 중앙부의 폭이 넓다. 아래, 위턱의 좌우에 끝이 날카로운 8∼11개의 이빨이 있다.

 

따스한 바다에서 약 300마리의 큰 무리를 지어 생활하며, 주로 오징어나 물고기를 잡아먹는다. 먹이는 통째로 먹지 않고 잘게 찢어서 먹는다. 성숙한 암컷의 임신기간은 15∼16개월이며, 7년에 1회 계절에 관계 없이 새끼를 낳는다. 수명은 암컷의 경우 최대 62년이고, 수컷의 경우 최대 56년이다.

 

우리 나라에는 수온이 17℃ 이상이 되는 5∼7월에 출현한다. 수십 마리에서 수백 마리가 무리를 이루며 무리의 지도자를 따라 큰 무리가 동시에 좌초하는 예가 많다. 어류와 오징어를 주 먹이로 하며 소형 고래류와 대형 고래류를 공격하기도 한다. 이 때는 소형 돌고래류들처럼 민첩하다. 대형 낚시어구의 미끼를 탈취하는 등 어민들에게는 귀찮은 존재이기도 하다. 수족관에서 기르기도 하는데, 지능이 높아 잘 길들이면 재주를 부리기도 한다. 근해성이며 온대와 열대역, 전해역에 서식한다

 

◈ 북태평양 (서부) : 16,668 마리.

◈ 북태평양 (동부 열대역) : 37,800 마리.

 

 

                

 

                

 

                

 

                

 

                

 

                

 

               

 

Although its common name is the false killer whale, Pseudorca crassidens is actually a member of the dolphin family. Males can reach 6.1m in length, while females are smaller, reaching 5m. Newborns are usually between 1.5~1.8m.

The distinguishing features of this species include having a long and slender body with a round and tapered head. The head has no beak and a long mouth that is curved at the gape. The flippers are long and narrow with a distinct hump on the leading edge. The dorsal fin is located near mid body. There are 8~11 large, conspicuous teeth in each jaw.

False killer whales are gregarious and often form herds containing more than a hundred individuals. These herds often associate with other species of dolphins, particularly bottlenose dolphins. The herds usually contain animals of both sexes and all ages. These animals are considered primarily oceanic, and only seem to approach land when there is deep water nearby. They are often seen playing in and riding the bow waves of ships and often jump completely out of the water.

Pseudorcas feed primarily on squid and large fish. They have been known to steal fish from the lines of fishermen. They have also been seen attacking dolphins escaping seine nets in the eastern tropical Pacific. It is this behavior that gives them their name, because like true killer whales (Orcinus orca), they eat other marine mammals.

The TMMSN has responded to four false killer whale strandings since 1980. However, 3 were found dead. These animals are known to mass strand occasionally. They are widely distributed in warm temperate and tropical waters around the world. They are not considered abundant in any region and are occasionally intentionally taken for food in Japan and accidentally caught in tuna long-line fisheries.

 

False Killer Whales are one of a number of species of ocean dwelling marine mammals also known as Blackfish. The distribution of the False Killer Whale is tropical to warm temperate waters in both hemispheres.

False Killer Whales are dark gray to black with a light blaze on the sides of the head and on the belly between the flippers. Their most distinctive and diagnostic feature is the shape of the pectoral fin with a bow-like front edge curving back to a pointed tip. The head is long and tapers to a small rounded snout that overshadows the lower jaw. The dorsal fin is small and hooked. The body long and slender.

False Killer Whales are more demonstrative at the surface than other "Blackfish" species, leaping and racing in response to the presence of moving boats. When jumping they appear to be pitch black but underwater the subtle markings are evident. They hunt and socialize in small groups but may form pods of 100~200. False Killer Whales are very social, hunting and sharing their food amongst the pod. They feed on squid, small fish and pelagic fish such as Yellowfin Tuna and Mahi Mahi.

To see an example of group feeding enter the Image Database and enter the number 44638 in the Keyword Search field or use the Category Tree to navigate to False Killer Whale (Pseudorca crassidens) via Mammals-Whales-Toothed Whales. The image shows a group of male and female adult False Killer Whales feeding on a Yellowfin Tuna with a newborn calf, with birth folds evident on its flanks, joining in. During the feeding session one adult would hold the fish while others tore off strips of flesh. The sound of their feeding was like tearing apart strips of velcro. Calves are born at 1.5m and grow to 4.7m if female and 6.1m if male.

The False Killer Whale is found in all oceans of the world, including the Mediterranean and Red Seas. It prefers mainly offshore waters in deep tropical, subtropical and warm temperate seas.

 

Classification

The False Killer Whale was first known from a skeleton from Lincolnshire, England, and Owen named it Phocaena crassidens. A mass stranding in 1860 proved its continued existence (something that had been in doubt) and after examining the animals, Danish zoologist Johannes Reinhardt amended the classification to Pseudorca crassidens, referring to this cetacean's resemblance to the Orca (Killer Whale). The specific name, crassidens, means 'thick-tooth', and is a reference to this species' robust teeth. This species is quite separate to the Orca.

 

Description

The False Killer Whale is a small and slim cetacean, with a tapering, rounded snout that overhangs the lower jaw, upon which there are between 8~11 pairs of teeth, matching the upper jaw. Above the mouthline, a crease trails from below the eye to the tip of the head. The dorsal is curved and located around halfway along the rounded body. The flippers have a broad hump on the leading edge which resembles a shoulder. The body colour is predominantly black, save for the odd faint grey marks on the head and throat. Males and females reach a maximum length of 5.96m and 5.1m respectively. Maximum weight in males is 2.2t ; in females, 1.1t.

 

Recognition at sea

 The False Killer Whale can be identified by their size and head shape; the latter and the shape of the dorsal are also useful in distinguishing them from Pilot Whales. Also, this is the only 'Blackfish' to bow-ride and swim rapidly at the surface.

 

Habitat

False Killer Whales tend to prefer warm temperate, subtropical and tropical waters, mainly in either semi-enclosed seas or in the open ocean away from land. Occasionally individuals have been spotted as far north as the northern UK, Norway and Alaska.

 

Food & Feeding

False Killer Whales prey mainly upon squid and large fish (such as tuna and dolphinfish), but have been known to attack groups of small cetaceans. This species has a bad reputation for taking bait from fishermen's lines.

 

Behaviour

The typical family unit contains between 10~50 individuals, but this cetacean is highly social and groups of several hundred are also common. A fast-swimming species, the False Killer Whale often gets excited, and porpoises (leaping clear of the water whilst swimming), bow-rides, and chases faster vessels. It has adapted well to captivity and is easily trained, showing much less aggression that the Pygmy Killer Whale. Mass strandings are common; in one case, over 800 individuals were found ashore.

 

Threats
◈ Direct catch
Pseudorca are occasionally taken in Japan for food and in St. Vincent Island, Caribbean for meat and cooking oil.

 

◈ Incidental catch
Incidental take of small numbers of false killer whales in gill nets has occurred off northern Australia, the Andaman Islands, the southern coasts of Brazil and in tuna purse seines in the eastern tropical Pacific. Dolphin entrapment in tuna purse seine nets may be providing artificial feeding opportunities for Pseudorca on other marine mammals. Yang et al. report on by-catch rates in Chinese coastal fisheries (trawl, gill and stow net) which may number in the hundreds per year for Pseudorca crassidens alone.