Perception Channels: tactile ; chemical
The IUCN lists Tasmacetus shepherdi under the "insufficiently known" category (Simmonds and Hutchinson 1996).
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: data deficient
none
Tasmacetus shepherdi is not economically important.
These whales eat squid and various fishes. Many of these fishes are benthic, suggesting that Tasmacetus shepherdi feeds at or near the sea floor (Tinker 1988).
Animal Foods: fish; mollusks
Primary Diet: carnivore (Molluscivore )
Although the geographic range of this species is not clearly known, Tasmacetus shepherdi (Shepherd's beaked whale, Tasman whale) probably has a circumpolar distribution in temperate waters of the southern hemisphere. All known specimens have been found on beaches in New Zealand, Australia, Brazil, Tierra del Fuego, Argentina, Chile, and the Galapagos Islands (Evans 1987, Tinker 1988).
Biogeographic Regions: indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )
Based on stomach contents and locations where Tasmacetus shepherdi have washed ashore, this species is likely benthic and inhabits temperate waters of the southern hemisphere (Evans 1987, Tinker 1988).
Aquatic Biomes: benthic
The body of these whales is around 6-7 meters in length. The head is small with a long, narrow beak. The dorsal fin is small and is located 1/3 of the body length from the tail. The tail fluke is not notched, and the flippers are small and oval in shape. The back is uniform grayish-brown in color, fading to nearly white on the underbelly. Since very few of these whales have been seen while alive and body colors quickly darken following death, the true coloration of Tasmacetus shepherdi is not known (Evans 1987, Tinker 1988).
Shepherd's beaked whale can be easily distinguished from other members of the family Ziphiidae by the presence of 17-29 conical teeth in both the upper and lower jaw. Males possess two additional teeth on the anterior most part of the lower jaw. These teeth, described as possessing "bulbous bases and conical crowns", are larger than the homodont cheek teeth, and are separated from the cheek teeth by a 4 cm diastema. One tooth sits on either side of the mandibular symphysis (Walker 1975, Evans 1987, Tinker 1988).
The blowhole is crescent in shape and is asymmetrically located on the left side of the top of the head. The eye sits directly below the blowhole. The first five vertebrae are fused and the first through seventh pairs of ribs possess two heads (Evans 1987, Tinker 1988).
Range mass: 5600 to 6500 kg.
Range length: 6 to 7 m.
Other Physical Features: endothermic ; bilateral symmetry
Very little is known about this rarely sighted whale. As of 1996, Tasmacetus shepherdi have been seen alive on only two occasions. Only around 10 beached specimens have ever been examined. The species was first described and named in 1937 and is the sole member of its genus. T. shepherdi is regarded as the most primitive ziphiid whale (Evans 1987, Harrison and Bryden 1988, Tinker 1988, Laughlin 1996).
Nothing is currently known about the reproduction of this species.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Shepherd's beaked whale (Tasmacetus shepherdi), also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphiidae and the only species in the genus Tasmacetus. The whale has not been studied extensively. Only four confirmed at sea sightings have been made and 42 strandings recorded (as of 2006). It was first known to science in 1937, being named by W. R. B. Oliver after George Shepherd, curator of the Wanganui Museum, who collected the type specimen near Ohawe on the south Taranaki coast of New Zealand's North Island, in 1933.[3][4]
Adults can reach lengths of 6 metres (20 ft) to 7.1 metres (23 ft) and weigh about 2.32 to 3.48 tons. At birth they may be about 3 metres (9.8 ft) long. They are robust and large-bodied for beaked whales, having a bluff melon and a long, dolphin-like beak.[5] It is the only species of ziphiid with a full set of functional teeth (17 to 27 pairs in both the upper and lower jaws).[4] Adult males also have a pair of tusks at the tip of the lower jaw. They are dark brown dorsally and cream-colored ventrally, with a pale band extending up from the flipper and another pale area extending as a swathe on the posterior flank. The tall, falcate dorsal fin is set about two-thirds the way along the back.[5]
Sightings and stranding records indicate that the species has a circumpolar distribution in southern hemisphere.[6] No population estimates exist for Shepherd's beaked whale. As of 2006, there have been about 42 stranding records of the species from New Zealand (including the Chatham Islands, 24), Argentina (7), Tristan da Cunha (6), Australia (3), and the Juan Fernández Islands (2). The northernmost record was at Shark Bay in Western Australia in 2008.[7] There have been five unconfirmed sightings (mostly from New Zealand), as well as a "probable" sighting near Shag Rocks and four confirmed sightings—the first two confirmed sightings occurred in 1985, within a few minutes of each other, off the Tristan da Cunha group (first sighting at ); the third in 2002 near Gough Island (); and the fourth in 2004 south of Tasmania ().[8] In January 2012, a group of up to a dozen of this species were photographed and filmed by the Australian Antarctic Division south of Portland, Victoria.[9]
Multiple sightings of the species have been reported from Otago submarine canyons off Otago coast, New Zealand. Sightings have been recorded throughout the year with vocalization recordings, suggesting regular presences there.[10] These include at least two sightings in 2016 which were the first confirmed sightings within New Zealand waters,[11] followed by four sightings in 2017,[12][13] one or more sighting(s) in 2018,[14][15] one sighting in 2019,[16] four or five sightings in 2021,[17][18][19][20][21] five sightings in 2022 including a pod of 15-20 animals.[10][22][23][24]
There have been additional sightings from other parts of New Zealand, such as off Gisborne,[25] several sightings off Kaikoura,[26][27][28] off Fiordland,[29] Taranaki,[30] and so on.
Four of the confirmed sightings of this species involved three to six individuals (one group included a calf) in waters from 350 metres (1,150 ft) to 3,600 metres (11,800 ft) deep, while a 2012 sighting involved as many as ten to twelve individuals. The animals surfaced several times, before arching to dive. Some were observed to come to the surface at a steep angle like many other ziphiids, raising their head and beaks out of the water.[8] The Shepherd's beaked whale's blow could be observed with the naked eye at a distance of up to 1,000 metres, within a bushy plume that is relatively tall for a ziphiid varying from 1 to 2 metres in height [31]
The species is seldom seen because of its deep, offshore distribution in waters where sighting conditions can be difficult (the "Roaring Forties" and "Furious Fifties").[8]
Research done on a stranded individual's stomach has indicated that Shepherd's beaked whales eat both fish and squid, as opposed to most beaked whales which only eat cephalopods.[32]
There are no reports of this species being hunted or killed accidentally by humans. Shepherd's beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).[33]
Its nearest relative, the only other living member of the subfamily Ziphiinae, is Cuvier's beaked whale (Ziphius cavirostris).
{{cite journal}}
: CS1 maint: multiple names: authors list (link) Shepherd's beaked whale (Tasmacetus shepherdi), also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphiidae and the only species in the genus Tasmacetus. The whale has not been studied extensively. Only four confirmed at sea sightings have been made and 42 strandings recorded (as of 2006). It was first known to science in 1937, being named by W. R. B. Oliver after George Shepherd, curator of the Wanganui Museum, who collected the type specimen near Ohawe on the south Taranaki coast of New Zealand's North Island, in 1933.