New Zealand Whales and Dolphins
Tursiops is well known for its playfulness and affection towards man; it is thought to be second only to man in intelligence. Several overseas and one New Zealand (Napier) marinelands have the species in captivity and have found that it adapts quickly to life in a pool, is quick to learn tricks, and is an ideal subject for study. A great deal has been found out about the animal's echolocating capabilities and its social behaviour (including communication). Military interest has been shown in the dolphin's ability to work for and with humans, and a 1971 press report indicates that it has been used to assist divers in the Vietnam War.
In New Zealand Bottlenose Dolphins are commonly seen in the Bay of Islands, outer Hauraki Gulf, and Marlborough Sounds, where they often follow ships. They have been reported to be capable of 20 knots. The famed ‘Opo George’ which mingled with swimmers at Opononi in Northland during the summer of 1955-56 was a female of this species. There are two specimens in the Napier Marineland.
Risso's Dolphin grows to about 13ft and is fairly deep in the body with a thin tail region. The head has a distinct ‘melon’ — it bulges forward and slopes very steeply down to the mouth. There is no trace of a beak. The Grampus lower jaw is unusual in that it has three to seven pairs of teeth up to half an inch in diameter placed only near the tip of the jaw. In young animals the teeth have recurved tips, but with increasing age they become rounded like .44 bullets. There are usually no teeth in the upper jaw.
Risso's Dolphin is found in tropical and temperate regions of most oceans but seems to be a rare visitor to the South Pacific. It has been recorded only four times in New Zealand. A lower jaw of this species was found on Manawatu Beach in 1867 and a pair of Risso's Dolphins stranded on Orongorongo Beach near Wellington as this article was going to press in 1972. The famous dolphin ‘Pelorus Jack’, which rode the bow waves of steamers passing across the outside of Pelorus Sound and Admiralty Bay, Marlborough, between 1888 and 1912, was also a Risso's Dolphin. There were many curious and conflicting stories written about Pelorus Jack, including some which told of the dolphin's existence as early as the early 1870s, and others which suggested he was an albino outcast that actually sought the company of ships and piloted them across the outer Marlborough Sounds. Pelorus Jack was protected by an Order in Council in 1904 after an attempt was made to shoot the animal from one of the steamers. The dolphin was last seen in April, 1912, and his disappearance was accounted for in various stories ranging from natural death to being harpooned by foreign whalers.
Dusky And Hourglass Dolphins
Lagenorhynchus obscurus and Lagenorhynchus cruciger
The Dusky Dolphin has virtually no beak, as the head slopes evenly down from the blowhole to the tip of the snout. The mouth slopes up towards the eye and contains twenty-nine to thirty-five pairs of small teeth about one-eighth of an inch in diameter in both jaws. The tip of the erect dorsal fin does not taper to a sharp point, but is rather blunt.
The Dusky is fairly common from Hawke Bay south to Fiordland, is attracted to ships, and has been successfully tamed and trained at Napier Marineland. A second species of this genus, L. cruciger or the Hourglass Dolphin, is thought to occur to the south of New Zealand, and may occasionally straggle close to the coast. There have been reports of it to the southeast of the Chatham Islands, but a positive identification from direct examination is needed to confirm its occurrence in our waters.page 29
The Hourglass Dolphin is similar in shape to the Dusky, but as its name suggests, the colour pattern is different. The animal is dark dorsally and dark pigment extends in a band from around the eye of the flipper, and back along the flanks as a wide patch. Just below the dorsal fin the lateral dark area attenuates and continues to the tailstock as a thin band. The remainder of the animal is white, and the dark patch on the flanks effectively divides the white areas to give an hourglass-like pattern. This is apparently a cold-water, oceanic species, which spends most of its time in antarctic and subantarctic seas.
Striped And Spotted Dolphins
Stenella caeruleoalba and Stenella dubia
The Striped Dolphin, or Euphrosyne Dolphin as it has been called, is similar in shape and colour tonings to the Common Dolphin. It is larger, however, reaching 10ft at full maturity, and has a distinctive colour pattern. Stenella is brownish-black dorsally, becoming lighter towards the tail. The beak, lower edge of the mouth, flippers, and tail are all dark, and there are dark stripes extending from the eyes to the flippers and the eyes to the vent. There may also be a short, light blaze rising from the flanks behind the eyes and curving up towards the dorsal fin. Both jaws contain about thirty-nine to forty-six pairs of small teeth.
A second species of Stenella, S. dubia or the Spotted Dolphin, may also occasionally stray into New Zealand waters from the north. A skull of this species was found in Golden Bay in 1869. The Spotted Dolphin grows to about 8ft, and has between thirty-eight and forty-five pairs of teeth in the upper jaw and thirty-seven to forty-one in the lower jaw. The colour pattern seems to vary considerably, but is basically dark grey dorsally and whitish ventrally, with an overlay of small light spots on dark areas and dark spots on light areas. It should be easy to recognise in New Zealand waters, for it would be the only dolphin with a spotted colour pattern in the region. This species normally lives near coastal areas and islands in tropical seas, and there may be several geographical races in different oceans.
Common Or Saddleback Dolphin
Delphinus frequents coastal waters all around New Zealand and often occurs in huge schools of several thousand individuals. It is a playful animal at sea and has responded very well to training in marinelands here.
Right Whale Dolphin
This beautifully streamlined dolphin shares its name with the Right Whale because both are lacking a dorsal fin. It is the only dolphin in New Zealand waters which has no dorsal fin (except perhaps for a stray Black Finless Porpoise), yet despite this easily recognisable character it has only rarely been seen at sea, and only one stranded specimen has been reported. It has a very slight beak which merges smoothly with the head, and each jaw contains forty-three pairs of small teeth. The animal grows to about 8ft and the body is very slender, particularly towards the tail. The colour pattern is most striking: the dorsal surface is jet black, and this colour curves down from the forehead passing between the eye and the corner of the mouth and sweeps up past the flipper towards the back before dipping again and levelling off through to the tail. The rest of the body is white except for the back edge of of the flipper, which is black. When swimming, this dolphin resembles a giant penguin.
This dolphin can be recognised at once by its small, rounded dorsal fin — the trailing edge is convex rather than concave as in all other New Zealand dolphins. It is a small dumpy animal growing to a maximum size of 5ft; the flippers are rounded at the tips, there is no beak, and the mouth slopes up towards the eye. There are twenty-seven to thirty-two pairs of small teeth in each jaw.
Hector's Dolphin is an inshore coastal species and is often found in muddy or discoloured water seaward of river mouths. It is common around the northern half of the South Island, and has been reported from Kawhia, Hauraki Gulf, and the Bay of Islands. There is one specimen in captivity at Marineland of New Zealand at Napier.
False Killer Whale
This species is found in all temperate and tropical seas and often travels in schools of several hundred. There have been a number of mass strandings of Pseudorca in various parts of the world involving up to 200 individuals. Three mass strandings have occurred in the New Zealand region, including one of 100 animals on the Chatham Islands in 1906.
The flanks of this animal are a uniform dark brownish-grey colour, which darkens noticeably near the head and on the dorsal fin, flippers, and tail. There may be a lighter patch just behind the dorsal fin, and the edge of the mouth is pinkish. The ventral surface of the body is dark grey anteriorly and lighter elsewhere, except for a wide, sharply demarcated M-shaped area of pinkish-grey just anterior to the flippers. This lighter area merges with the grey of the belly about level with the flippers except for right on the mid-ventral line, where a thin band of pinkish-grey extends down the body to the vent. In young Pilot Whales there is a very fine dark line within the thin band.
There have been many strandings of Globicephala on the New Zealand coast, including several of over 100 individuals.
The Killer Whale is a powerful, solid-looking dolphin which grows to 31ft. The head is fat but pointed and there is a very slight rounded beak. The flippers are big, rounded paddles, and the dorsal fin is very tall (up to 6ft) and sharply triangular. There are eleven to thirteen pairs of large conical teeth in each jaw. The colour pattern is very striking, with distinct black and white areas. The animal is black from the tip of the snout to the trailing edge of the tail, except for a white patch above the eyes and a light grey saddle just behind the dorsal fin. On the underside, the white extends from the tip of the lower jaw through to the tail flukes, and rises up the flanks in a rounded, tailwards-pointing patch just ahead of the genital region.
Black Finless Porpoise
The Black Finless Porpoise is a small, stout animal with a rounded, slightly protruberant forehead. There is a depressed area along the midline of the back within which lies a low ridge bearing tiny tubercles. There are fifteen to nineteen spade-like teeth on each side of the upper and lower jaws.
Except for ventral dark grey patches between the flippers and around the vent, the porpoise is entirely black in colour. It is usually a solitary animal.
Any specimens of this species seen at sea or washed ashore around New Zealand should be reported to a museum, so that its occurrence here can be confirmed.
This ‘Moby Dick’ of the whales is the largest cetacean to have teeth. The conical teeth grow to about eight inches long and there are usually around twenty-five pairs in the lower jaw. The upper jaw has small vestigial teeth which hardly break through the gums. The Sperm Whale is very distinctive-looking, with its huge box-like head and underslung lower jaw. In place of the normal dorsal fin, there is a series of hump-like ridges along the midline of the back towards the tail. The colour is purplish-brown or dark grey dorsally and grey or white underneath. It grows to about 60 feet.
Sperm Whales were hunted by the Tory Channel Whaling Station in the 1960s in the waters of Cook Strait. Dr D. E. Gaskin studied the Cook Strait Sperm Whale population and found that they were more numerous in summer, and that the fluctuation in numbers was related to the movement of surface water from the warm East Cape current. The water temperatures in summer are favourable for schooling squid, the main food item of local Sperm Whales. He also found that some whales, particularly solitary males, remain in Cook Strait all the year, while the rest move northward about 2° latitude for winter breeding.
Sperm Whales are fairly common stranders on the New Zealand coast and there have been seven mass strandings recorded, involving a total of 175 animals. In March 1970 fifty-nine Sperm Whales stranded at Wainui near Gisborne; this was a typical ‘nursery school’ of females with calves and young adults of both sexes. A ‘bachelor school’ of seven young males stranded at the tip of Farewell Spit in September, 1970, and another nursery school of thirty went ashore on Great Barrier Island in May, 1972.page 37
Ambergris is a solid, waxy substance secreted in the Sperm Whale's intestine, which has been used in medicines, perfumes, and even as an aphrodisiac. It is sometimes found floating in the sea or washed up on beaches. As a perfume fixative it once fetched $40 an ounce, but is now worth only between 75c and $3 an ounce.
Ambergris looks rather like dark kauri gum but is lighter and much softer. It can be recognised by its dark brownish-black colour and sweet musky smell which is enhanced by warming. A hot needle will melt it into a dark shining liquid which will burn with a luminous flame. Ambergris sometimes contains squid beaks and it is thought to be comparable to the intestinal stones and hair balls found in land mammals.
Pygmy Sperm Whale
There have been twenty-three strandings recorded on the New Zealand coast and most have been single animals, although occasionally a cow and calf have come ashore together. Little is known about the biology of these whales, but examination of stranded animals has shown that they feed on squids, shrimps, crabs, and fishes. There is an excellent cast of a 9ft specimen, which stranded at Lyall Bay, Wellington in 1950, on display at the Dominion Museum. An attempt was made to keep a recently stranded Kogia in an aquarium at Napier's Marineland a few years ago, but the animal kept butting its head against the wall of the pool and eventually died. Post mortem examination showed that it was extensively diseased and could not have survived.
Shepherd's Beaked Whale
Only five specimens are known and all have stranded on the New Zealand coast. The first three came ashore at Stewart Island (two) and Wanganui (one) in 1933, and more recently (1951, 1962) two specimens stranded near Christchurch. Nothing is known about its biology and very little information is available on its external appearance.
The Scamperdown Whale is a fairly regular strander on the New Zealand coast, fifty-three having been recorded since 1873. A mass stranding of twenty-five occurred on the Chatham Islands last century.
Hector's And Andrew's Beaked Whales
Mesoplodon hectori and Mesoplodon bowdoini
There is insufficient information on the outward appearance of these two beaked whales in New Zealand waters to enable accurate illustrations to be made. There are skeletons in the Dominion Museum, however, and the diagnostic features of the two species can be illustrated by reference to the lower jaws and teeth (Fig. 7). Hector's Beaked Whale has a small pair of flat triangular teeth almost at the tip of the lower jaw. Andrew's Beaked Whale has a pair of large flattened teeth set in partly raised sockets situated just behind the area where the two lower jaws are fused together (the symphysis). The teeth are convex on the hinder margin and have a small denticle at the tip which projects forwards and outwards.
Both Hector's and Andrew's Beaked Whales are probably fairly small, as the existing skeletons are up to only 14ft in length.
Figure 7: Lower jaws and teeth of New Zealand Beaked Whales. Arrow marks position of hind margin of symphysis.
Despite the fact that over twenty Strap-Toothed Whales have stranded on the New Zealand coast, hardly anything is known about the biology of this species.
Cuvier's Or Goose-Beaked Whale
The Goose-Beaked Whale grows to a maximum size of 32ft, but animals in the 20-25ft range are more common around New Zealand. The colour is variable, but seems to be either grey, fawn, or purplish-black on the back and lighter on the belly and around the head. The body may also have white oval blotches and scars.
There have been a number of strandings of this species around Bank's Peninsula and the Golden Coast north of Wellington. In Hawke Bay recently a specimen was saved from stranding and assisted back to sea by Alex Dobbins of Marineland of New Zealand.
Large Beaked Whale
There have been nineteen strandings of this species recorded in New Zealand, mostly around the Cook Strait area during summer.
Southern Bottlenose Whale
The Bottlenose Whale is very rare in New Zealand waters, its occurrence here being based on the fragments of two lower jaws found near East Cape and Timaru, respectively. The species has stranded in Australia however, and the following description is based on the Australian records. The body is solid, the tail flukes are wide, and there is a distinct beak protruding from a very bulbous forehead. The forehead actually slopes forward to overhang the base of the beak. There is one pair of short, conical teeth situated at the tip of the lower jaw sloping forwards and slightly outwards. Each tooth has a central, peaked denticle.