Beaked whale
Beaked whales are 21 species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of toothed whales, members of the family Ziphiidae, are notable for their elongated beaks. Beaked whales are one of the world's most extreme divers. They can dive for long periods—20 to 30 minutes is common, and 85 minute dives have been recorded—and to great depths: 1899 metres (1,038.4 fathom) and possibly more. To avoid getting decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...

—the potentially fatal build-up of nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 bubbles in body tissues—they must surface slowly.

Beaked whales are one of the least known groups of mammals because of their deep-sea habitat, mysterious habits, and apparent low abundance. Several species have yet to be formally described or named; others are known only from remains and have never been sighted alive. Only three to four of the 21 species are reasonably well-known. Baird's and Cuvier's beaked whale
Cuvier's Beaked Whale
Cuvier's beaked whale is the most widely distributed of all the beaked whales. It is the only member of the genus Ziphius. Another common name for the species is goose-beaked whale because its head is said to be shaped like the beak of a goose. Georges Cuvier first described it in 1823 from part...

s were subject to commercial exploitation, off the coast of Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, while the Northern bottlenose whale was extensively hunted in the northern part of the North Atlantic late in the 19th and early in the 20th centuries.

Physical characteristics

Beaked whales are moderate in size, ranging from 4 to 13 m (13.1 to 42.7 ft) and weighing from 1 to 15 t (0.984203533290685 to 14.8 ). Their key distinguishing feature is the presence of a 'beak', somewhat similar to many dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s. Other distinctive features include a pair of converging grooves under the throat, and the absence of a notch in the tail fluke. Although Shepherd's beaked whale
Shepherd's Beaked Whale
Shepherd's beaked whale , also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphidae. The whale has been little studied. Only four confirmed at sea sightings have been made and 42 strandings recorded . It was first known to science in 1937, being...

 is an exception, most species have only one or two pairs of teeth, and even these do not erupt in females. Beaked whale species are often sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

—one or the other sex is significantly larger. The adult males often possess a dramatically bulging forehead. However, aside from dentition and size, there are very few morphological differences between male and female beaked whales.

Individual species are very difficult to identify in the wild, since body form varies little from one species to another. The observer must rely on often subtle differences in size, color, forehead shape, and beak length.


Beaked whales are unique among toothed whales in that most species only have one pair of teeth. The teeth are tusk-like but are only visible in males, which are presumed to use these teeth in combat for female reproductive rights. In females, the teeth do not develop and remain hidden in the gum tissues. This characteristic helps to distinguish beaked whale species from each other.

In December 2008, researchers from the Marine Mammal Institute at Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...

 completed a DNA tree of all 21 known species of beaked whales. Among the results of this study was the conclusion that the male's teeth are actually a secondary sexual characteristic, similar to the antler
Antlers are the usually large, branching bony appendages on the heads of most deer species.-Etymology:Antler originally meant the lowest tine, the "brow tine"...

s of male deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

. Each species' teeth have a characteristically unique shape. Females are presumed to select mates based on the shape of the teeth, because the different species are otherwise quite similar in appearance. Females may also choose mates based on the size or shape of teeth or the scars they bear.

These teeth also play an important role in competing to control a harem.


Beaked whales comprise at least 21 species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

 in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Ziphiidae, which is one of the least-known families of large mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s: several species have been described only in the last two decades. Six genera
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 have been identified.

The beaked whales are the second-largest family of Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

ns (after the dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s.) They were one of the first groups to diverge from the ancestral lineage. The earliest known beaked whale fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s date to the Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, about 20 million years ago.
    The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

  • Suborder Odontoceti: toothed whales
    • Family Ziphiidae
      • Subfamily Berardiinae
        • Genus †Archaeoziphius
        • Genus Berardius
          • Berardius arnuxii, Arnoux's beaked whale
          • Berardius bairdii, Baird's beaked whale
        • Genus †Microberardius
      • Subfamily Hyperoodontinae
        • Genus †Africanacetus
        • Genus Hyperoodon, bottlenose whales
          • Hyperoodon ampullatus, Northern bottlenose whale
          • Hyperoodon planifrons, Southern bottlenose whale
        • Genus Indopacetus
          • Indopacetus pacificus, Longman's beaked whale
        • Genus Mesoplodon, Mesoplodont whales
          • Mesoplodon bidens, Sowerby's beaked whale
            Sowerby's Beaked Whale
            Sowerby's beaked whale , also known as the North Atlantic/North Sea beaked whale, was the first beaked whale to be described. James Sowerby, an English naturalist and artist, first described the species in 1804 from a skull obtained from a male that had stranded in the Moray Firth, Scotland, in 1800...

          • Mesoplodon bowdoini, Andrews' beaked whale
            Andrews' Beaked Whale
            Andrews' beaked whale , sometimes known as the deep-crest beaked whale or splay-toothed whale, is one of the most poorly known members of a poorly known genus...

          • Mesoplodon carlhubbsi, Hubbs' beaked whale
            Hubbs' Beaked Whale
            Hubbs' beaked whale was initially thought to be an Andrews' beaked whale when discovered by ichthyologist Carl Hubbs; however, it was named in his honor when it was discovered to be a new species. This species has the typical dentition found in the genus, but its main outstanding features are a...

          • Mesoplodon densirostris, Blainville's beaked whale
            Blainville's Beaked Whale
            Blainville's beaked whale , or the dense-beaked whale, is the widest ranging mesoplodont whale and perhaps the most documented. Henri de Blainville first described the species in 1817 from a small piece of jaw—the heaviest bone he had ever come across—which resulted in the name densirostris...

          • Mesoplodon europaeus, Gervais' beaked whale
            Gervais' Beaked Whale
            Gervais' beaked whale , sometimes known as the Antillian beaked whale, Gulf Stream beaked whale, or European beaked whale is the most frequently stranding type of mesoplodont whale off the coast of North America...

          • Mesoplodon ginkgodens, Ginkgo-toothed beaked whale
            Ginkgo-toothed Beaked Whale
            The ginkgo-toothed beaked whale is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth...

          • Mesoplodon grayi, Gray's beaked whale
            Gray's Beaked Whale
            Gray's beaked whale , sometimes known as Haast's beaked whale, the Scamperdown whale, or the southern beaked whale, is one of the better-known members of the genus Mesoplodon. The scientific name refers to John Edward Gray, a zoologist at the British Museum. This species is fairly gregarious and...

          • Mesoplodon hectori, Hector's beaked whale
            Hector's Beaked Whale
            Hector's beaked whale , is a small mesoplodont living in the Southern Hemisphere. This whale is named after Sir James Hector, a founder of the colonial museum in Wellington, New Zealand...

          • Mesoplodon layardii, Strap-toothed whale
          • Mesoplodon mirus, True's beaked whale
            True's Beaked Whale
            The True's Beaked Whale is a medium sized whale in the Mesoplodont genus. The common name is in reference to Frederick W. True, a curator at the United States National Museum...

          • Mesoplodon peruvianus, Pygmy beaked whale
            Pygmy Beaked Whale
            The pygmy beaked whale , also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp...

          • Mesoplodon perrini, Perrin's beaked whale
            Perrin's Beaked Whale
            Perrin's beaked whale is the newest species of beaked whale to be described. The first two specimens were found in May 1975 stranded on the California coast, with two more specimens being found in 1978 and 1979, and the last in September 1997...

          • Mesoplodon stejnegeri, Stejneger's beaked whale
            Stejneger's Beaked Whale
            Stejneger's beaked whale , sometimes known as the Bering Sea beaked whale or the Saber-toothed whale, is a poorly-known member of the genus Mesoplodon inhabiting the northern North Pacific Ocean. Leonhard Hess Stejneger initially described the species in 1885 from a skull, and nothing more of the...

          • Mesoplodon traversii, Spade-toothed whale
      • Subfamily Ziphiinae
        • Genus †Caviziphius
        • Genus †Izikoziphius
        • Genus Tasmacetus
          • Tasmacetus sheperdi, Shepherd's beaked whale
        • Genus Ziphius
          • Ziphius cavirostris, Cuvier's beaked whale
      • Subfamily Incertae sedis
        Incertae sedis
        , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

        • Genus †Nenga
        • Genus †Pterocetus
        • Genus †Xhosacetus

Evolutionary history

As many as eight genera antedate humans. Some included ancestors of giant beaked whales (Berardius), such as Microberardiusand Cuvier's beaked whale (Ziphius) had many relatives, such as Caviziphius, Archaeoziphius, and Izikoziphius. They were probably preyed upon by predatory whales and shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

s, including Carcharocles megalodon
The megalodon and ὀδούς ) is an extinct species of shark that lived roughly from 28 to 1.5 million years ago, during the Cenozoic Era .The taxonomic assignment of C...


Recently, a large fossil ziphiid sample was discovered off the South African coast, confirming the extant ziphiid diversity might just be a remnant of a higher past diversity. After studying numerous fossil skulls off the shore of South Africa, researchers discovered the absence of functional maxillary teeth in all South African fossil ziphiids, which is evidence that suction feeding had already developed in several beaked whale lineages during the Miocene. Researchers also found fossil ziphiids with robust skulls, signaling that tusks were used for male-male interactions (speculated with extant beaked whales).


Beaked whales are deep divers with extreme dive profiles They regularly dive deeper than 500 m to echolocate for food, and these deep dives are often followed by multiple shallower dives of less than 500 m. Based on currently available data, beaked whales are thought to spend much of their lives below water.

Deep-diving mammals face a number of challenges related to extended breath holding and hydrostatic pressure. Cetaceans and pinnipeds that prolong apnea must optimize the size and use of their oxygen stores, and they must deal with the accumulation of lactic acid due to anaerobic metabolism. Beaked whales have several anatomical adaptations to deep diving: large spleens, livers, and body shape. Most cetaceans have small spleens. However, beaked whales have much larger spleens than delphinids, and may have larger livers as well. These anatomical traits, which are important for filtering blood, could be adaptations to deep diving. Another notable anatomical adaptation among beaked whales is a slight depression in the body wall that allows them to hold their pectoral flippers tightly against their bodies for increased streamlining.

The challenges of deep diving are also overcome by the unique diving physiology of beaked whales. Oxygen storage during dives is mostly achieved by blood hemoglobin and muscle myoglobin. While the whale is diving, its heart rate slows and blood flow changes. This physiological dive response ensures oxygen-sensitive tissues maintain a supply of oxygen, while those tissues tolerant to hypoxia receive less blood flow. Additionally, lung collapse obviates the exchange of lung gas with blood, likely minimizing the uptake of nitrogen by tissues.


The throats of all beaked whales have a bilaterally paired set of grooves that are associated with their unique feeding mechanism, suction feeding. Instead of capturing prey with their teeth, beaked whales suck it into their oral cavity. Suction is aided by the throat grooves, which stretch and expand to accommodate food. Their tongue can move very freely. By suddenly retracting the tongue and distending the gular (throat) floor, pressure immediately drops within the mouth sucking the prey in with the water.

Dietary information is available from stomach contents analyses of stranded beaked whales and from whaling operations. Their preferred diet is primarily deep-water squid, but also benthic and benthopelagic fish and some crustaceans, mostly taken near the sea floor. In a recent study, gouge marks in the seafloor were interpreted to be a result of feeding activities by beaked whales.

To understand the hunting and foraging behavior of beaked whales, researchers used sound and orientation recording devices (DTAGs) on two species: Cuvier’s beaked whale (Ziphius cavirostris) and Blainville’s beaked whale (Mesoplodon densirostris). These whales hunt by echolocation in deep water (where the majority of their prey is located) between approximately 200 and 1885 m and usually catch about 30 prey per dive. Cuvier’s beaked whale must forage on average at 1070 m for 58 minutes and Blainville’s beaked whales typically forage at 835 m deep for an average of 47 minutes.

Range and habitat

The family Ziphiidae is one of the most widespread families of cetaceans, ranging from the ice edges at both the north and south poles, to the equator in all the oceans. Specific ranges vary greatly by species, though beaked whales typically inhabit offshore waters that are at least 300 meters deep.

Beaked whales are known to congregate in deep waters off the edge of continental shelves, and bottom features, such as seamounts, canyons, escarpments, and oceanic islands, including the Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...

 and the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...


Life history

Very little is known about the life histories of beaked whales. The oldest one ever recorded was 84 years for a male Baird’s beaked whale, and the oldest recorded female Baird’s beaked whale is 54 years. For all other beaked whale species studied, the highest recorded age is between 27 and 39 years. Sexual maturity is reached between seven and 15 years of age in Baird’s beaked whales and northern bottlenose whales. Gestation varies greatly between species, lasting 17 months for Baird’s beaked whales and 12 months for the northern bottlenose whale. There are currently no data available on their reproductive rates.

It is difficult to determine group size of beaked whales, due to their inconspicuous surfacing behavior. Groups of beaked whales, defined as all individuals found in the same location at the same time, have been reported as ranging from one to 100 individuals. Nevertheless, some populations’ group size has been estimated from repeated observations. For example, northern and southern bottlenose whales (H. ampullatus and H. planifrons), Cuvier’s beaked whales and Blainville’s beaked whales (Mesoplodon densirostris) have a reported maximum group size of 20 individuals, with the average ranging from 2.5 to 3.5 individuals. Berardius species and Longman’s beaked whales (Indopacetus pacificus) are found in larger groups of up to 100 individuals.

Not much information is available about group composition of beaked whales. Only three species have been studied in any detail: northern bottlenose whales, Blainville’s beaked whales, and Baird’s beaked whales. Female northern bottlenose whales appear to form a loose network of social partners with no obvious long-term associations. In contrast to females, some male northern bottlenose whales have been repeatedly recorded together over several years, and possibly form long-term associations. Studies of Blainville’s beaked whales have revealed groups usually consist of a number of females, calves and/or juvenile animals. These whales are assumed to live in "harem-like" groups, where several females and young are accompanied by a single male. Baird’s beaked whales are known to occur in multiple male groups, and in large groups consisting of adult animals of both sexes.


For many years, most beaked whale species were insulated from anthropogenic impacts because of their remote habitat. However, there are now several issues of concern:
  • Studies of stranded beaked whales show rising levels of toxic chemicals in their blubber
    Blubber is a thick layer of vascularized adipose tissue found under the skin of all cetaceans, pinnipeds and sirenians.-Description:Lipid-rich, collagen fiber–laced blubber comprises the hypodermis and covers the whole body, except for parts of the appendages, strongly attached to the musculature...

  • As a top predator, beaked whales, like raptor
    Bird of prey
    Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

    s, are particularly vulnerable to build-up of biocontaminants. They frequently ingest plastic bags (which do not break down and can be lethal).
  • They more frequently become trapped in trawl nets, due to the expansion of deepwater fisheries.
  • Decompression sickness

A major conservation concern for beaked whales (family Ziphiidae) is they appear to be vulnerable to modern sonar operations, which arises from recent strandings that temporally and physically coincide with naval sonar exercises. Postmortem examinations of the stranded whales in concurrence with naval exercises have reported the presence of hemorrhaging near the ears or gas and fat emboli, which could have a deleterious impact on beaked whales that is analogous to decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...

 in humans. Gas and fat emboli have been shown cause nervous and cardiovascular system dysfunction, respiratory distress, pain, and disorientation in both humans and animals. In the inner ear, gas embolism can cause hemorrhages, leading to disorientation or vestibular dysfunction.

Breath-holding divers, like beaked whales, can develop decompression-related problems (the “bends”) when they return to the surface after deep dives. This is a possible hypothesis for the mass strandings of pelagic beaked whales associated with sonar-related activities. To illustrate, a diving beaked whale may be surfacing from a deep dive and must pass vertically through varying received sound levels. Since the whale has limited remaining oxygen supplies at the end of a long dive, it probably has limited abilities to display any normal sound avoidance behavior. Instead, the whale must continue to swim towards the surface to replenish its oxygen stores. Avoiding sonar inevitably requires a change in behavior or surfacing pattern. Therefore, sonar in close proximity to groups of beaked whales has the potential to cause hemorrhaging or to disorient the animal, eventually leading to a stranding.

Current research reveals two species of beaked whales are most affected by sonar: Cuvier’s beaked whales (Z. cavirostris) and Blainville’s (M. densirostris) beaked whales. These animals have been reported as stranding in correlation with military exercises in Greece, the Bahamas, Madeira, and the Canary Islands. The livers of these animals had the most damage.

Though some evidence indicates sonar-related activities can actually lead to a form of decompression sickness in beaked whales, the topic is still up for debate. A significant limiting factor in determining the likelihood of bubble formation in whale tissues and the risk of decompression sickness is the lack of information on their normal diving and surfacing patterns. More research is necessary to determine the extent of whale tissue damage caused by sonar exercises.

Four species are classified by the IUCN as "lower risk, conservation dependent": Arnoux's and Baird's beaked whales, and the northern and southern bottlenose whale
Bottlenose whale
The Northern bottlenose whale is a species of the ziphiid family, one of two members of the Hyperoodon genus. The northern bottlenose was hunted heavily by Norway and Britain in the 19th and early 20th centuries...

s. The status of the remaining species is unknown, preventing classification.


Tracking their silent voices (original title: Auf der leisen Spur der Schnabelwale) is a documentary about an Atlantic scientific expedition. A team of marine biologists tried to find beaked whales and to analyze their behavior using acoustic methods only.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.