Beaked Whales (Ziphiidae)
Beaked whales
(Ziphiidae)
Class Mammalia
Order Cetacea
Suborder Odontoceti
Family Ziphiidae
Thumbnail description
Small- to medium-sized whales, characterized by a noticeable beak with no crease between it and the forehead, a single pair of throat grooves, a robust cigar-shaped body, small dorsal fin positioned two-thirds of the way along the body, large flukes lacking a central notch, and very reduced dentition with only one or two pairs of teeth that form tusks in most species
Size
13–42 ft (3.9–12.8 m)
Number of genera, species
6 genera; 21 species
Habitat
Deep ocean, particularly around seabed features such as canyons, seamounts, and escarpments
Conservation status
Lower Risk/Conservation Dependent: 4 species; Data Deficient: 15 species
Distribution
All oceanic waters deeper than 660 ft (200 m), from the ice edge to the equator
Evolution and systematics
The beaked whales were one of the first lineages to split from the ancestral group of toothed whales, and now form the second largest family of living species in the order Cetacea. Although some fossil beaked whales are known, it is not clear how these relate to modern species. Fossils may represent extinct lineages or ancestors to modern species. The genera Ziphius, Tasmacetus, and Indopacetus all contain a single species each, while the genera Berardius and Hyperoodon both contain two species. In contrast, the genus Mesoplodon contains 14 species. Currently, no beaked whale species is separated into subspecies.
Physical characteristics
Adult beaked whales range in body length from 13 ft (3.9m) in the pygmy beaked whale (Mesoplodon peruvianus) to 42 ft (12.8 m) in Baird's beaked whale (Berardius bairdii). With the exception of Cuvier's beaked whale (Ziphius cavirostris), all beaked whales have a noticeable beak, and in none of the species is there a crease between the beak and the forehead, which is found in other toothed whales. Between the lower jaws is a single pair of throat grooves that are used in feeding. The body is cigar-shaped, with the greatest girth occurring in the middle. The dorsal fin is relatively small, sub-triangular in shape, and is set two-thirds of the way along the body. The pectoral fins are also relatively small and can be held against the body in recessed flipper pockets. The tail flukes are broad and are unique in cetaceans in lacking a central notch. The dentition is greatly reduced in all species, except Shepherd's beaked whale (Tasmacetus shepherdi), which has only one or two pairs of teeth remaining in the lower jaw and none remaining in the upper jaw. In all species apart from those of the genus Berardius, these teeth erupt in adult males to form tusks, though they never erupt in adult females. The position and shape of the tusks vary between beaked whale
species and are the primary features used to identify species. The color of beaked whales varies from light brown to slate gray and black. In some species there are also areas of contrasting light colors, which can be sexually dimorphic. Adult males of many species are covered in long pale lines that are scars caused by the tusks of other males.
Distribution
Beaked whales have been recorded from all oceanic waters beyond the continental shelf edge and from the ice-edge at the poles to the equator. However, individual species generally have a more restricted distribution. Only two species, Cuvier's beaked whale and Blainville's beaked whale (Mesoplodon densirostris), have been recorded from more than two oceans, and some species appear to have a very restricted distribution, such as the newly described Perrin's beaked whale (Mesoplodon perrini), which to date has only been recorded from the waters along the coast of California.
Habitat
Beaked whales occupy deep oceanic waters of greater than 660 ft (200 m) beyond the edges of the continental shelf, with most sightings occurring in water depths between 3,300 and 9,900 ft (1,000–3,000 m). Sightings of living beaked whales are often concentrated around marine features such as canyons, seamounts, shelf edges, and escarpments.
Behavior
Beaked whales are generally seen in small groups of fewer than 10 animals, but group size and structure vary between species. Where studies exist, individual animals have been resighted within and between years in the same area, indicating some level of site fidelity. Some species of beaked whales show evidence of regular migrations.
Feeding ecology and diet
Beaked whales primarily feed on deepwater squid, fish, and occasionally crustaceans, ranging in sizes from a few ounces (grams) to several pounds (kilograms). The presence of bottom-living prey species as well as small stones in the stomachs of beaked whales suggests that they are capable of diving to the seabed in water depths of 3,300 ft (1,000 m) or more to forage. Prey capture is thought to occur by suction feeding, with animals using their piston-like tongues and expandable throat-grooves to suck prey into the mouth.
Reproductive biology
Single calves are the norm in beaked whales and these calves remain close to their mothers for at least the first year before being weaned. The presence of large sexually dimorphic weapons (the tusks) and the restriction of intraspecific scarring to adult males suggests that most species are polygamous, with adult males actively competing aggressively for access to receptive females.
Conservation status
Four beaked whale species are listed as Lower Risk/Conservation Dependent by the IUCN, and 15 are listed as Data Deficient, which reflects the lack of studies of these species.
The northern bottlenose whale was hunted commercially in the past, but in 1977 the population was considered to be depleted by the International Whaling Commission (IWC) and the fishery was closed.
Significance to humans
In general, beaked whales have little significance to humans. Three species of beaked whales have been commercially hunted by humans: the northern bottlenosed whale in the North Atlantic and Cuvier's beaked whale and Baird's beaked whale by the Japanese in the North Pacific. Other beaked whale species are occasionally taken in several parts of the world either as bycatch in fishing nets or from whale fisheries directed at other species.
Species accounts
List of Species
Northern bottlenosed whaleBaird's beaked whale
Cuvier's beaked whale
Blainville's beaked whale
Shepherd's beaked whale
Longman's beaked whale
Northern bottlenosed whale
Hyperoodon ampullatus
taxonomy
Hyperoodon ampullatus (Forster, 1770), Maldon, England.
other common names
English: Altantic bottlenosed whale, flathead, bottlehead; French: Grand souffleur à bec d'oie; German: Butskof; Spanish: Hocico de botella.
physical characteristics
Adult males reach up to 33 ft (10 m) in length, while adult females are noticeably smaller, reaching only 28 ft (8.5 m). The body is robust, with a large bulbous head and short beak. The forehead becomes more bulbous in adult males due to the growth of two large bony crests on the skull. The single pair of teeth found in the lower jaw remains relatively small and barely erupted even in the oldest males. Dark on the back, with a paler belly, although adult males may also have a pale area on the forehead.
distribution
Endemic to the polar to warm-temperate waters of the North Atlantic. They are regularly recorded from the Norwegian Sea, around Greenland, and off Labrador south to the Bay of Biscay, the Azores, and Nova Scotia, as well as further south.
habitat
Generally found in deep waters beyond the edge of the continental shelves and is usually seen in water depths of greater than 3,300 ft (1,000 m). Off the coasts of Nova Scotia, one population is regularly sighted over a deep marine canyon known as the Gully, however, northern bottlenose whales are also recorded over continental slopes and plateaus.
behavior
Usually occur in groups of about four individuals, although larger groups of more than 10 have been sighted. Adult males have been seen aggressively head-butting each other, using the large bony crests in their foreheads as battering rams, and such combat may relate to competition for females. Some populations may migrate, moving northward in late winter and spring and southward in late summer and autumn. However, other populations such as in the Gully off Nova Scotia are apparently nonmigratory.
feeding ecology and diet
In the northern North Atlantic, squid of the genus Gonatus are the most commonly consumed prey, although other squid species and deepwater fish are eaten in some locations. Northern bottlenose whales usually dive close to the seabed when foraging and can dive to depths of over 5,000 ft (1,500 m) for up to 80 minutes or more.
reproductive biology
Calves are born in late spring and summer after a gestation of approximately 12 months and will nurse for approximately another 12 months. Both males and females mature around the age of seven to 10 years. Adult males are larger than adult females,
and this species may well be polygamous, however the exact mating system remains unclear.
conservation status
In 1977, northern bottlenosed whales were declared depleted by the International Whaling Commission, and commercial whaling for this species ceased. It is currently classified as Data Deficient by the IUCN.
significance to humans
None known.
Baird's beaked whale
Berardius bairdii
taxonomy
Berardius bairdii (Stejneger, 1882), Commander Islands, Russia.
other common names
English: Northern four-toothed whale, giant bottlenosed whale.
physical characteristics
Reaches up to 39 ft (12 m) in males and 42 ft (12.8 m) in females. They have a noticeable beak with two pairs of teeth in the lower jaw and a relatively steep forehead. The teeth erupt to become functional in both males and females as they mature. Their bodies are generally dark gray or black all over, with adults gaining pale linear scars as they grow older.
distribution
Endemic to the North Pacific and found from as far south as Japan and Mexico, and north to Siberia, the Aleutian Islands, and Alaska.
habitat
Generally found in deep waters beyond the edge of the continental shelves and usually seen in water depths of greater than 3,300 ft (1,000 m). Most sightings occur over marine features such as seamounts, escarpments, and continental slopes.
behavior
Usually found in groups of up to 10 animals, although larger groups of up to 30 have been recorded; groups may contain several mature adults of both sexes. They typically dive for about 30 minutes or more and may dive to more than 3,300 ft (1,000 m) to feed.
feeding ecology and diet
Consumes deepwater squid and fish species.
reproductive biology
Despite being hunted, reproduction of Baird's beaked whales remains poorly known. The length of gestation is unclear, with some speculating that it lasts 10 months while others think it lasts 17 months; females may only produce a calf every three or so years. Males mature before females and apparently live longer. The mating system is unknown.
conservation status
Classified as Data Deficient by the IUCN.
significance to humans
The Japanese hunt Baird's beaked whales off the coasts of Japan and in the western Pacific. Other than this, this species has little significance to humans.
Cuvier's beaked whale
Ziphius cavirostris
taxonomy
Ziphius cavirostris G. Cuvier, 1823, France.
other common names
English: Goose-beaked whale; French: Ziphius de Cuvier; German: Cuvier-Schnabelwal; Spanish: Ballena de Cuvier.
physical characteristics
Up to 23 ft (7 m) in length and brown to tan in color. Adult males have pale heads and backs, and can be covered in large numbers of long pale scars caused by the tusks of other males. Their tusks are conical in shape, situated at the tip of the lower jaw, and only erupt to become functional in adult males.
distribution
The widest distribution of any beaked whale species, being found in tropical to cold-temperate waters of all the world's oceans.
habitat
Generally found in deep waters beyond the edge of the continental shelves and usually seen in water depths of greater than 3,300 ft (1,000 m). Sightings are often reported over marine features such as canyons, escarpments, and shelf edges.
behavior
Recorded in groups of up to seven animals. While at the surface, the most characteristic behavior is a three-quarter lunge out of the water, often in response to a close approach by a boat. Dives may last for more than 30 minutes and animals may reach depths of over 3,300 ft (1,000 m).
feeding ecology and diet
Consumes deepwater squid, fish, and crustaceans, and dives to great depths to capture them.
reproductive biology
Almost nothing is known about reproduction. Adult males are larger than females and have high levels of scarring caused by the tusks of other males. These features are consistent with a polygamous mating system.
conservation status
Classified as Data Deficient by the IUCN.
significance to humans
Taken in small numbers by Japanese whalers in the North Pacific. Other than this, Cuvier's beaked whales are of little significance to humans.
Blainville's beaked whale
Mesoplodon densirostris
taxonomy
Mesoplodon densirostris (Blainville, 1817), type locality unknown.
other common names
English: Dense beaked whale; German: Blainville-Schnabelwal.
physical characteristics
Between 15 and 16 ft long (4.5–5 m), with a relatively long beak and a noticeable arch midway along the lower jaw. In
adult males, this arch becomes enlarged and two large tusks erupt from the top. Younger animals are gray or dark gray on top and pale underneath, however adult animals are often brown, gray, or dark all over. In adult males, the head and back can be covered in a very large number of white scars caused by the tusks of other males.
distribution
Found in all tropical to warm-temperate waters around the globe, although they are most commonly recorded around oceanic tropical islands.
habitat
This species is recorded in shallower waters than most other beaked whale species and can be seen in water depths of as little as 330 ft (100 m). Around oceanic islands, most sightings are in water depths of less than 3,300 ft (1,000 m).
behavior
Relatively little is known about behavior other than the fact that they are deep-divers and often dive for up to 30 minutes or more. However, the heavy scarring found on adult males indicates that they engage in aggressive combat, presumably over access to females.
feeding ecology and diet
Deepwater squid and fish have been recorded in the stomachs of Blainville's beaked whales, and they are thought to forage at or close to the seabed.
reproductive biology
Apparently polygamous, with adult males competing aggressively with each other for access to females. Groups with more than one adult male are rarely recorded. However, males do not appear to remain with a single female group and may rove between them looking for receptive females. Calves remain close to their mothers for the first year, with weaning occurring after 12 months. Both sexes mature at around 10 years of age.
conservation status
Classified as Data Deficient by the IUCN. Although occasionally killed by fishermen, either purposefully or accidentally in fishing nets set for other species, this species has never been hunted commercially.
significance to humans
Generally unknown to most humans and, when encountered, few people even identify them correctly, most thinking they are large dolphins.
Shepherd's beaked whale
Tasmacetus shepherdi
taxonomy
Tasmacetus shepherdi Oliver, 1937, New Zealand.
other common names
English: Tasman beaked whale.
physical characteristics
Up to 23 ft (7 m) in length, with a long beak and rounded forehead. They are dark on the back, with lighter sides and belly. Has numerous small, peg-like teeth in both the upper and lower jaws as well as a pair of large sexually dimorphic tusks at the tip of the lower jaw.
distribution
All records come from the colder waters of the Southern Hemisphere; the majority of records come from New Zealand, with additional records from southern Australia, the Chatham Islands, Juan Fernandez Islands, Argentina, and South Africa.
habitat
With no confirmed sightings at sea, nothing is currently known about its habitat preferences.
behavior
Little is known about its behavior.
feeding ecology and diet
It is thought that deepwater fish may make up a greater proportion of the diet of Shepherd's beaked whale than other beaked whales, although this is based on stomach contents analysis from a single animal.
reproductive biology
Nothing is known about its reproductive biology.
conservation status
Classified as Data Deficient by the IUCN.
significance to humans
Shepherd's beaked whale was only discovered in 1937, and has had little significance to humans.
Longman's beaked whale
Indopacetus pacificus
taxonomy
Indopacetus pacificus (Longman, 1926), Queensland, Australia.
other common names
English: Indopacific beaked whale.
physical characteristics
The only two definite records consist of two skulls. From this, it has been estimated that this species is about 23 ft (7 m) long. Possible sightings are of animals about 23–26 ft (7–8 m) long, with a moderately long beak and bulbous forehead and varying in color from tan to grayish brown.
distribution
The two definite records of Longman's beaked whale were found on a beach in Queensland, Australia, and in a fertilizer factory in Somalia. However, possible sightings have been recorded from the tropical waters of the Pacific and Indian Oceans.
habitat
This species' habitat is not known.
behavior
Sightings of possible Longman's beaked whales are of groups of animals usually between 15 and 20 animals, although some groups number up to 100.
feeding ecology and diet
Nothing is known, as it has never been seen in the wild.
reproductive biology
Nothing known.
conservation status
Classified as Data Deficient by the IUCN.
significance to humans
None known.
| Common name / Scientific name/Other common names | Physical characteristics | Habitat and behavior | Distribution | Diet | Conservation status |
| Arnoux's beaked whale Berardius arnuxii English: Southern four-toothed whale, southern giant bottlenosed whale; French: Bérardien d'Arnoux; Spanish: Ballena de pico de Arnoux | Dark or dark brown, often covered with many long, thin white scars. Long beak and steeply sloping forehead. Both males and females have only two pairs of teeth, found in the lower jaw. These erupt to become functional only in adults. Body length 25–30 ft (7.8–9.7 m). | Groups of up to 80 individuals. Found in deep open waters, along the ice edge, and in open areas within seasonal ice fields. | Southern oceans from Brazil, South Africa, and Australia south to the Antarctic ice edge. | Deepwater squid and fish. | Lower Risk/Conservation Dependent |
| Southern bottlenosed whale Hyperoodon planifrons English: Antarctic bottlenosed whale, flathead; French: Hyperoodon austral; Spanish: Ballena hocico de botella del sur | Dark brown, dark or slate gray. Short beak and bulbous forehead, particularly in adult males. Reduced dentition with only one pair of teeth at the tip of the lower jaw that erupt beyond the gums only in adult males. Body length 19–25 ft (6–7.5 m). | Generally seen in groups of one or two. Found in deep waters. May dive to great depths to feed. | Southern oceans from Brazil, South Africa, and Australia south to the Antarctic ice edge. | Deepwater squid and fish. | Lower Risk/Conservation Dependent |
| Andrew's beaked whale Mesoplodon bowdoini English: Splay-toothed beaked whale, Bowdoin's beaked whale; French: Mesoplodon de Bowdoin; Spanish: Ballena de pico de Andrew | Dark blue-black or brown with white tip to beak, males may have long, thin, white scars on body. Short beak and gently sloping forehead, adult males have two large tusks in middle of lower jaw. Body length 13–16 ft (4–4.7 m). | There are no confirmed sightings of this species in the wild, so habitat use and behavior remain unknown. | Most of the 35 known records are from New Zealand, with additional records from the southern coast of Australia, the Falkland Islands and Tristan da Cunha. Apparently restricted to southern temperate waters south to the Antarctic Convergence. | Unknown. | Data Deficient |
| Sowerby's beaked whale Mesoplodon bidens English: North Sea beaked whale; French: Mesoplodon de Sowerby; Spanish: Ballena de pico de Sowerby | Dark gray or brown on top, paler underneath. Long, narrow beak, gently sloping forehead. Reduced dentition with only a single pair of teeth in the middle of the lower jaw that form tusks in adult males. Body length 14.8–18.2 ft (4.5–5.5 m). | Generally seen in groups of fewer than ten animals. Found in deep waters of several thousand feet (meters) or more and may dive to great depths to feed | Temperate to subpolar North Atlantic from Norway, Iceland, and Labrador south to the Azores and northern United States. | Deepwater fish and squid. | Data Deficient |
| Hubbs' beaked whale Mesoplodon carlhubbsi English: Arch-beaked whale; French: Mesoplodon de Hubbs; Spanish: Ballena de pico de Hubbs | Dark gray or black with a white tip to the beak and a white cap, males may have high levels of thin white scars all over the body. Relatively short beak with a noticeable arch in the middle of the lower jaw. Reduced dentition with only a single pair of teeth in the middle of the lower jaw that form tusks in adult males. Body length 16.5–18.2 ft (5.0–5.5 m). | Rarely seen in the wild; habitat use and behavior remain unknown. | Temperate waters of the North Pacific along the coast of Japan and continental North America from Mexico to southern Canada. | Deepwater squid and fish. | Data Deficient |
| Gervais' beaked whale Mesoplodon europaeus English: Antillean beaked whale, Gulf Stream beaked whale, European beaked whale; French: Mesoplodon de Gervais; Spanish: Ballena de pico de Gervais | Dark gray or brown on top, paler underneath. Relatively short beak and steep forehead. Reduced dentition with only a single pair of teeth in the one third of the jaw length from the tip of the lower jaw. Body length 14.8–17.2 ft (4.5–5.2 m). | Rarely seen in the wild; habitat use and behavior remain unknown. | Warm temperate to tropical waters of the Atlantic on both sides of the equator. | Deepwater squid, fish, and crustaceans. | Data Deficient |
| Ginkgo-toothed beaked whale Mesoplodon ginkgodens English: Japanese beaked whale; French: Mesoplodon de Nishiwaki | Dark gray or brown all over. Relatively short beak and smoothly sloping forehead. Reduced dentition with only a single pair of teeth in the middle of the lower jaw that only barely erupt in adult males. Body length 14.8–17.2 ft (4.5–5.0 m). | Rarely seen in the wild; habitat use and behavior remain unknown. | Recorded from Mexico, southwestern United States, Galápagos Islands, Japan, Taiwan, Sri Lanka, Malaysia, New South Wales, Australia, and New Zealand. | Unknown. | Data Deficient |
| Common name / Scientific name/Other common names | Physical characteristics | Habitat and behavior | Distribution | Diet | Conservation status |
| Gray's beaked whale Mesoplodon grayi English: Southern beaked whale; French: Mesoplodon de Gray; Spanish: Ballena de pico de Gray | Dark gray or brown with a white beak and face in some individuals. Long, narrow beak, gently sloping forehead. Reduced dentition with only a single pair of teeth in the middle of the lower jaw that form tusks in adult males. Body length 14.8–18.2 ft (4.5–5.5 m). | Groups of four or five have been sighted, but one stranding had about 28 animals. Generally seen in deep water far from shore. | Temperate to subpolar waters of the Southern Hemisphere. | Deepwater squid. | Data Deficient |
| Hector's beaked whale Mesoplodon hectori English: Skew-beaked whale; French: Mesoplodon d'Hector; Spanish: Ballena de pico de Héctor | Dark gray or brown on top, paler underneath with a white beak. Short beak with only two triangular teeth close to the tip of the lower jaw that erupt only in adult males. Body length 13.2–14.9 ft (4–4.5 m). | Rarely seen in the wild; habitat use and behavior remain unknown. | Very small number of records from Tasmania, New Zealand, South Africa, Argentina, and the Falkland Islands. | Unknown, but probably deepwater squid and fish. | Data Deficient |
| Strap-toothed whale Mesoplodon layardii English: Layard's beaked whale; French: Mesoplodon de Layard; Spanish: Ballena de pico de Layard | Dark gray or black with white areas on belly, throat and on the back behind the head. Long, narrow beak, gently sloping forehead. Adult males have two tusks that emerge from the middle of the lower jaw and cross over the upper jaw. Body length 16.5–20.5 ft (5.0–6.2 m). | Occasionally sighted in deep waters far from shore in small groups. | Throughout the Southern Hemisphere from 30°S to the Antarctic Convergence. | Deepwater squid. | Data Deficient |
| True's beaked whale Mesoplodon mirus French: Mesoplodon de True; Spanish: Ballena de pico de True | Dark gray or brown on top, paler underneath with a dark patch around the eyes. Relatively short beak and steeply sloping forehead beak. Reduced dentition with only a single pair of teeth of conical teeth at the tip of the lower jaw that form tusks in adult males. Body length 16.2–17.5 ft (4.9–5.3 m). | Few, if any, positive sightings at sea; habitat use and behavior remain unknown. | Temperate North Atlantic from Ireland to the Canaries and the eastern seaboard of the United States and Nova Scotia, Canada, as well as records in South Africa and Australia, indicating that a separate Southern Hemisphere population also exists. | Deepwater squid. | Data Deficient |
| Perrin's beaked whale Mesoplodon perrini | Dark gray or brown on top, paler underneath with a white beak. Short beak with only two triangular teeth close to the tip of the lower jaw that only erupt in adult males. Body length 13.2–14.9 ft (4–4.5 m). | Known only from five stranded animals and two possible sightings; habitat use and behavior remain unknown. | All currently known records come from the waters of California, United States, but the species may have a wider distribution. | Unknown. | Not listed by IUCN |
| Pygmy beaked whale Mesoplodon peruvianus English: Peruvian beaked whale lesser beaked whale; French: Mesoplodon pygmée | Dark gray or brown on top, paler underneath. Males may have a pale flank and back as well as numerous pale white scars. Short beak and gently sloping forehead. Slight curve in lower jaw and only a single pair of teeth set on a slightly raised area of the lower jaw. Body length up to 12.8 ft (3.9 m). | Groups of one to five animals have been seen in deep oceanic waters. | Most records come from the eastern tropical Pacific from Peru to Mexico out to about 126°W, with an additional record from New Zealand. | Deepwater fish. | Data Deficient |
| Stejneger's beaked whale Mesoplodon stejnegeri English: Bering Sea beaked whale; French: Mesoplodon de Stejneger; Spanish: Ballena de pico de Stejneger | Dark brown, gray, or black all over with the exception of white on the beak and underside of the tail. Males may have many narrow, pale scars on the back. Long, narrow beak grading into a gently sloping forehead. Single pair of teeth set in the middle of the lower jaw that are visible only in adult males. Body length 16.5–17.5 ft (5–5.5 m). | Groups of up to 15 animals have been seen in deep waters ranging from 2,500 to 5,000 ft (750–1500 m) deep over continental slope areas | Cold temperate to subpolar North Pacific from as far south as California and Japan to Siberia, the Aleutian Islands, and Alaska. | Deepwater squid. | Data Deficient |
| Spade-toothed whale Mesoplodon traversii French: Zifo de travers; Spanish: Baleine a bec de Travers | Known only from three skulls. The most distinguishing feature is a single pair of spade-shaped teeth set in the middle of the lower jaw. | Habitat use and behavior remain unknown. | Of the three currently known records, two are from New Zealand and one is from Robinson Crusoe Island, Chile. | Unknown. | Not listed by IUCN |
Resources
Books
Balcomb, Kenneth. "Baird's Beaked Whale Berardius bairdii, Stejneger, 1883; Arnoux's Beaked Whale Berardius arnuxii." In Handbook of Marine Mammals. Vol. 4, River Dolphins and Larger Toothed Whales, edited by Samuel Ridgway and Richard Harrison. London: Academic Press, 1989.
Heyning, John. "Cuvier's Beaked Whale Ziphius cavirostris." In Handbook of Marine Mammals. Vol. 4, River Dolphins and Larger Toothed Whales, edited by Samuel Ridgway and Richard Harrison. London: Academic Press, 1989.
Mead, James. "Beaked Whales of the Genus Mesoplodon." In Handbook of Marine Mammals. Vol. 4, River Dolphins and Larger Toothed Whales, edited by Samuel Ridgway and Richard Harrison. London: Academic Press, 1989.
——. "Bottlenose Whales Hyperoodon ampullatus (Forster, 1770) and Hyperoodon planifrons (Flower, 1882)." In Handbook of Marine Mammals. Vol. 4, River Dolphins and Larger Toothed Whales, edited by Samuel Ridgway and Richard Harrison. London: Academic Press, 1989.
——. "Shepherd's Beaked Whale Tasmacetus shepherdi Olivier, 1937." In Handbook of Marine Mammals. Vol. 4, River Dolphins and Larger Toothed Whales, edited by Samuel Ridgway and Richard Harrison. London: Academic Press, 1989.
Reeves, Randall, Brent Stewart, Phillip Clapham, and James Powell. Sea Mammals of the World. London: A&C Black, 2002.
Colin D. MacLeod, PhD