Beaked Whales: Species, Characteristics, Behavior | Sea Life, Islands and Oceania

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BEAKED WHALES

Sowerby's beaked whale

Beaked whales look like oversized dolphins They have beaks like dolphins and prey on deep water fish and squid. Little is known about them because they are shy and spend much of their time in deep water. They use echolocation to navigate and hunt and have been involved in incidents in which whales were beached by U.S. navy sonar. Even when dead, many species of beaked whales, are very difficult to distinguish from one another because they lack easily discernable or apparent physical characteristics. Nearly all have a greatly reduced number of teeth. Beaked whales tagged and outfit with transmitters off of Italy produced very, short clicking noises at ultrasonic frequencies that started when the animals reached a depth of 200 meters (650 feet) with the echolocation continuing to the depth of 1,260 meters (4,150 feet).

Beaked whale species are difficult to distinguish from one another because they all have a similar appearance. Identification is further complicated by their relatively small body sizes, elusive and shy behavior around humans, and inconspicuous blow. Because beaked whales are hard to distinguish in the wild, much of the information about them is generalized to the entire genus. [Source: NOAA]

Most beaked whales are considered “data deficient” by the International Union for Conservation of Nature’s list of threatened species, meaning that there is not enough information to assess their population status. The Convention on International Trade in Endangered Species (CITES) places several species in Appendix II, which lists species not necessarily threatened with extinction now but may become so unless trade is closely controlled: They are protected throughout their range. By Marine Mammal Protection Act (MMPA): The main threats to them are entanglement in fishing gear and ocean noise.

Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se; Encyclopedia of Life eol.org; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems ; Monterey Bay Aquarium montereybayaquarium.org ; MarineBio marinebio.org/oceans/creatures

Ziphiids

beaked whale attacked by an orca

Ziphiidae (beaked whales) is the second largest family of cetaceans (whales, porpoises and dolphins) after the Delphinidae (oceanic dolphins). The Ziphiidae family includes 24 species in six genera. Its members are found in all oceans. Ziphiids (members of the Ziphiidae family) are a diverse group, but little is known about them and a few have been studied. But as a rule they are capable of prolonged deep dives. All feed on squid; some also include fish in their diets. Social groups, as best can be surmised, consist of 3 to 40 individuals. Some ziphiids were pursued by whalers for their oil and spermaceti. [Source: Phil Myers, Animal Diversity Web (ADW) /=]

Ziphiids (members of the Ziphiidae family) are medium-sized whales, up to around 13 meters (43 feet) in length and 11.5 tonnes (12.8 US tons, 11,500 kilograms, 25,350 pounds). According to Animal Diversity Web: They have distinctive, long and narrow beaks. In some species, the snout is sharply set off from the rest of the head by a bulging forehead as in members of the Delphinidae; in others, however, the profile across the forehead is relatively flat. Their flippers are relatively small and oval to gently pointed in shape. Beaked whales have a small, falcate dorsal fin, which is set fairly far back on their bodies (well beyond the midpoint). The trailing edge of the fluke has no notch, unlike other cetaceans. Ziphiids have up to six short grooves on their throats. These converge anteriorly, forming a V pattern. The body color of these whales varies among species from uniform brown or gray to having contrasting white markings.[Source: Phil Myers, Animal Diversity Web (ADW) /=]

The skulls of ziphiids have an expanded facial depression like that of delphinids, but its posterior margin is very much raised. The zygomatic arch is small and hidden from dorsal view beneath the sides of the facial depression. The rostrum is very narrow, and the palate is strongly convex. The lower jaw is V-shaped and is as wide or slightly wider than the rostrum. The mandibular symphysis is relatively short, less than 1/3 the length of the ramus. The teeth vary greatly among species in number, from 19/27 in Tasmanian beaked whales to 0/1-2 in all other genera. Males of all species have one or two large functional teeth on the lower jaw; smaller, apparently non-functional teeth are sometimes seen on upper and lower jaws of several species. The teeth of females of most species remain buried in the gums, suggesting that ziphiid teeth are used mostly in social encounters. /=\

Mesoplodon Beaked Whales

Mesoplodont whales are the largest group of beaked dolphin — comprising at least 16 species of toothed whale in the genus Mesoplodon. Two species were described as recently as 1991 (pygmy beaked whale) and 2002 (Perrin's beaked whale), and marine biologists predict the discovery of more species in the future. A new species was described in 2021. The generic name "mesoplodon" comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'. [Source: Wikipedia]

Mesoplodon whales belong to the Family Ziphiidae. Despite being one of the most diverse groups of marine mammals, they are the most poorly known group of large mammals. They are often identified by a combination of their head and skull shape backed up by molecular genetic analysis, to prevent misidentification.

20120522-beached whale conduct_autopsy_on_stranded_beaked_whale.jpg
stranded beaked whales
Mesoplodon whales occupy most oceanic environments, excluding the coldest Arctic oceans. They use echolocation (emitting sound waves and sensing their reflections to determine the location of objects) to help find their food and move around in their environments. They range in size from about four to six meters (13 to 19 feet) in length. There are indications that males use their beaks and teeth to fight with other males in their species, possibly for mates or high-ranking in groups. [Source: Meredith Martin, Animal Diversity Web (ADW)]

Mesoplodon beaked whales live in temperate, tropical, saltwater and marine environments in all the world’s seas and are usually found in the open ocean far from land. Species are quite widespread. Many of them can dive to depths of 2,000 meters or more and spend much of their time deep water. They can also occasionally be found in the 200-meter to 2,000-meter region on the the continental slope, but almost never pass over into the continental shelves themselves. Individual species are often localized, residing in a single ocean, region or hemisphere.

Beaked Whale Characteristics, Feeding and Reproduction

Beaked whales are endothermic (use their metabolism to generate heat and regulate body temperature independent of the temperatures around them).: Females are larger than males and sexes may be colored or patterned differently. Mesoplodon genus has a number of defining characteristics, especially in relation to their skulls. They have a long rostrum (snout), creating the beaked appearance that provides their common name. Their rostrums also vary in shape, size, and teeth placement. Teeth characteristics vary between species and sometimes sex. [Source: Meredith Martin, Animal Diversity Web (ADW) /=]

Mesoplodons have one dorsal fin that has a triangular shape about two-thirds down their spindle-shaped body. They have small narrow flippers. Along their back, they have a semi-circle blowhole that isn't always symmetric. In terms of as coloring, young and females are the most indistinguishable, they have a gray-ish brown dorsal area and become paler on the ventral side, this nondescript color causes them to blend in as sea. Adult males are more identifiable as they have more distinguishing colors and patterns, most often consisting of black and/or white patches on different parts of the body based on species. These coloring patterns in males can be caused by normal pigmentation or scarring.

Based on examining Mesoplodon stomach contents, it appears beaked whales feed primarily on squid. Some species eat deep and middle open ocean fish. Their main known predators are orcas (killer whales). Echolocation (emitting sound waves and sensing their reflections to determine the location of objects) is the primary, sometimes only, sensory method in Mesoplodons, It is especially useful in locating prey. According to Animal Diversity Web: Mesoplodons are able to navigate narrow fields of 20 degrees through radiating sounds by sampling 1.5 to three clicks per meter traveled. By doing this they can select and approach prey using a minimum of 60 clicks. This has resulted in Mesoplodons being able to classify prey at more than a 15-meter range, having this large of a detection range paired with their swimming speed created a mode of sensory-motor operation allowing them to optimize their energy during long and deep dives. In comparison to air, sound travels at a rate of 4.5 times faster underwater which helps enhance the echolocation abilities of Mesoplodon whales.

There is not much information about beaked whale reproduction. They are believed to be polyandrous (with females mating with several males during one mating season) or polygynous (males having more than one female as a mate at one time). Females give birth a single offspring per calving event. Many species are thought to mate according to breading hierarchies that are created through the intraspecies fighting among males. These fights are often to defend territories that the females value and defend the females themselves, Most likely calves are born during the spring or summer.

Longman's beaked whales

Beaked Whales Behavior, Diving and Communication

Beaked whales are motile (move around as opposed to being stationary),migratory (make seasonal movements between regions, such as between breeding and wintering grounds), social (associates with others of its species; forms social groups), and have dominance hierarchies (ranking systems or pecking orders among members of a long-term social group, where dominance status affects access to resources or mates). [Source: Phil Myers, Animal Diversity Web (ADW) /=]

Beaked whale have been observed rolling several times before disappearing under the surface. They are often spotted breaching the surface in groups, which scientists believe indicate that they communicate underwater while foraging for food. It is believed that the males use teeth that females don’t have to fight the hierarchical battles, especially when mating.

In recent years technology has been used to determine how long whales can remain underwater and how deep they dive. In one study a Blainville's beaked whale recorded in Hawaii dove for 50-70 minutes at a time, reaching a maximum depth of around 1400 meters. Meanwhile, in a different study, another Blainville's beaked whale was recorded spending double that amount of time in shallower waters possibly to recover from the oxygen debt from the longer and deeper dives. /=\

Beaked whales sense using touch, sound,echolocation (emitting sound waves and their reflections to determine the location of objects) vibrations, and chemical cues. They communicate with sound and echolocation vibrations. They use echolocation mainly to forage, locate, and catch prey. It has been estimated that they can identify thousands of organisms through the use of echolocation during foraging dives. Vocalizations of only a few species — namely Hubbs' beaked whale and Blainville's beaked whale — have been recorded. They have different and distinct click types that are thought to be be associated with foraging.

Gervais's Beaked Whales

Gervais’s beaked whales (Scientific name: Mesoplodon europaeus) are sometimes called the "Antillean" or "Gulf Stream beaked whale." They prefers deep tropical, subtropical, and warm temperate waters of the Atlantic Ocean but is occasionally found in colder temperate seas. There is little information on their numbers but may be the most commonly sighted species of the Mesoplodon genus off the U.S. Atlantic coast and the Gulf of Mexico. They are also the most common beaked whale to strand on the U.S. southeastern Atlantic coast. The estimated lifespan of this species is at least 27 years but may be up to 48 years. [Source: NOAA]

Gervais’s beaked whale

Most of what is known about Gervais’s beaked whales is from stranded individuals. Recorded from as far north as New York and as far south as Trinidad, Gervais’s beaked whales, they are usually found in the open ocean far from land. Records from the eastern side of the Atlantic are more spotty, but have been documented as far north as Ireland and as far south as Guinea Bissau in Africa. A relationship is thought to exist between water temperature and prey species distribution, which in turn affects the distribution of different Mesoplodon species. /=\

The stomach contents of stranded Gervais’s beaked whales has revealed primarily squid (Octopoteuthis spp., Mastigoteuthis spp. and Taonius spp.), deep sea mysid shrimp (Neognathophausia ingens) and mesopelagic viper fish (Chauliodus sloani and Nesiarchus nasutus). While diving, they use suction to feed. Their stomach is divided into multiple chambers. The purpose of this is undetermined, as squid and fish are easily digested, as opposed to the tough material eaten by most animals with such stomach morphology. Their main known predators are killer whales (Orcas) and cookie-cutter sharks. [Source: Tawny Seaton, Animal Diversity Web (ADW) /=]

Gervais’s beaked whales are listed “ Data Deficient” on the International Union for Conservation of Nature (IUCN) Red List. They are hunted in the Caribbean Sea for food and have been incidentally taken as bycatch in fishing gear, such as pound nets and potentially in driftnets and gillnets. Deep-diving cetaceans like Gervais’s beaked whales use sound to feed, communicate, and navigate in the ocean. They may be sensitive to underwater sounds and man-made noise. Sound pollution threatens them by interrupting their normal behavior and driving them away from areas important to their survival, such as feeding and breeding waters. [Source: NOAA]

Gervais's Beaked Whales Characteristics and Behavior

Gervais's beaked whales adults are about 4.6 to 5.2 meters (15 to 17 feet) in length. They can weigh over 1200 kilograms (2,645 pounds). Females may be slightly larger than males. Mature males can be distinguished from females and juveniles by two visible teeth that emerge from the front portion of their bottom jaw. These two teeth are are visible outside the mouth as small “tusks” near the front of the rostrum. Females and juveniles also have teeth, but they remain hidden beneath the mouth’s gum tissue. Gervais's beaked whales typically have straight or slightly curved jawlines. [Source: NOAA]

Gervais's beaked whales have a relatively small to medium-size body with a moderately long beak and an indistinct sloping forehead (or melon). They have a small, triangular, wide-based, slightly hooked dorsal fin located far down the back. Their coloring is dark gray or bluish to black, with a paler ventral side. They tend to become darker as they age. Both females and males often have a pronounced dark patch around the eye. Females and young males may have a series of small, faint, wavy stripes down the centerline of the back. Mature males may also have linear scars from battles over females; however, scarring is generally not heavy with this species.

Gervais's beaked whale

Gervais's beaked whales are usually found individually or in small closely associated social groups. They are motile (move around as opposed to being stationary), and social (associates with others of its species; forms social groups). At sea, Gervais’ beaked whales are challenging to observe and identify to the species level because of their cryptic, skittish behavior; low profile; and a small, inconspicuous blow at the water’s surface. They sense using touch and chemicals usually detected with smell. /=

Gervais's beaked whales are viviparous, meaning they give birth to live young that developed in the body of the mother. Females may become sexually mature at 4.5 meters (15 feet). A sexually mature female will give birth to a single newborn calf that is about 2.1 meters (7 feet) long and weighs about 80 kilograms (176 pounds). Young are precocial. This means they are relatively well-developed when born. Pre-fertilization, pre-birth and pre-weaning provisioning and protecting is done by females.

Sowerby's Beaked Whale

Sowerby's beaked whales (Scientific name: Mesoplodon bidens) are also called "North Atlantic beaked whale". The first beaked whale to be discovered, this species lives in temperate and subarctic waters throughout the North Atlantic Ocean, but has also been reported near the ice pack. Their scientific name, bidens, is derived from the Latin words bi for "two" and dens for "teeth" and refers to the pair of visible teeth that erupt from the lower jaw of mature males. [Source: NOAA]

Sowerby's beaked whales prefer the deep, cold temperate and subarctic waters off the continental shelf edge are are distributed throughout the North Atlantic Ocean from 30° to 71° North, ranging from the Norwegian Sea, Labrador Sea, Iceland, and Baltic Sea to the north, and waters off the northeast United States, Madeira, and the Canaries to the south. Sowerby’s beaked whales may be more common in the eastern than the western North Atlantic Ocean. However, they rarely occur in the Mediterranean Sea. Strandings have occurred in Florida and Italy, but these areas are considered outside their normal range. Their distribution may vary depending on the movements of oceanographic currents. It is unknown whether they undertake seasonal movements or migrations.

Adult Sowerby's beaked whales range in length from 4.4 to 6.4 meters (14.5 to 21 feet) and weigh 1,000 to 1,315 kilograms (2,200 to 2,900 pounds). Males, which are generally larger, can be distinguished from females and juveniles by a pair of visible lower jaw teeth. Females and juveniles also have teeth, but they remain hidden beneath the gum tissue, and their jawline is straight. Sowerby's beaked whales have a small- to medium-sized body with a very long, slender beak relative to other beaked whales, as well as a bulge on the forehead area. The beak often emerges at a steep angle when surfacing. They have a small, wide-based, slightly hooked dorsal fin located about two-thirds down their back. Most of their body is charcoal gray with a pale underside, and calves are generally darker than adults. The lower jaw is usually light gray or white. This species has less visible scarring than most other beaked whale species. [Source: NOAA]

Sowerby's beaked whale

Sowerby's beaked whales are usually found individually or in small, closely associated groups averaging between three and 10 individuals. Regular dives range from 10 to 15 minutes, but dives of at least 28 minutes and reaching depths up to 1,500 meters (4,920 feet) have been recorded. While diving, they use suction to feed on small, deep-sea fish and cephalopods (such as, squid) in deep waters. When surfacing, this species often lifts its head up out of the water at a 45-degree angle. Sowerby's beaked whales may reach sexual maturity at about age 7, and their breeding season may be from late winter to spring. A sexually mature female will give birth to a single newborn calf that is about 2.4 to 2.6 meters (8 to nine feet) long and weighs about 170 kilograms (375 pounds).

Stejneger's Beaked Whale

Stejneger's beaked whales (Scientific name: Mesoplodon stejnegeri) are sometimes known as the "Bering Sea beaked whale" or "saber-toothed whale". They receive their common and scientific name from Leonhard Stejneger, a naturalist and curator at the Smithsonian Institution, who first described the species from a single skull discovered on Bering Island in 1885. This species prefers the cold, temperate, and subarctic waters of the North Pacific Ocean and is generally found in deep, offshore waters on or beyond the continental slope. Stejneger's beaked whales usually make five to six shallow dives followed by a longer dive that lasts 10 to 15 minutes and may reach depths of 4,920 feet. While diving, they use suction to feed on small deep-water fish, tunicates, and cephalopods (such as, squid). [Source: NOAA]

There is little information on Stejneger's beaked whales numbers to the rarity of sightings at sea. are generally found in deep, offshore waters between 760 to 1,525 meters (2,500 and 5,000 feet) on or beyond the continental slope. Stejneger's beaked whales are found throughout the North Pacific that includes California, the Aleutian Islands, the southwest Bering Sea, Kamchatka, the Okhotsk Sea, and the Sea of Japan. Strandings of this species have commonly occurred in the Aleutian Islands of Alaska and on the west coasts of Japan. Scientists speculate that Stejneger's beaked whales may migrate north in the summer. Information on their distribution mostly comes from stranding records. Although they face threats from entanglement in fishing gear, human-caused noise, and marine debris, Stejneger's beaked whales in the United States are not endangered or threatened.

Stejneger's beaked whales reach 5.7 meters (18.7 feet) in length. They weigh up to 1,600 kilograms (3,527 pounds( Their lifespan is estimated to be at least 35 years. Females may be slightly larger than males. Males can be easily distinguished from females and juveniles by a pair of large, visible, forward-pointing, tusk-like teeth that erupt from their arched lower jaw. Females and juveniles also have teeth, but they remain hidden beneath the gum tissue of the mouth, and their jawline is generally less curved.

Stejneger's beaked whale

Stejneger's beaked whales have a relatively medium-sized, round body with a small, wide-based, slightly hooked dorsal fin located about two-thirds down their back. They have a low-sloping, indistinct forehead (known as a melon). Their coloration varies from dark gray to brownish and black. A dark cap that extends across the top of the head from eye to eye, and the lower jaw is usually white or pale gray. The skin may be covered with linear and oval-shaped scars and other markings. Individuals, especially mature males, accumulate more scars and scratches with age. Mature males will battle each another for access to females.

Stejneger's beaked whales are usually found individually or in small, tight social groups averaging between five and 15 individuals. These groups may contain animals of mixed sexes, ages, and life stages, or they can be segregated. Like most beaked whales, this species is difficult to approach and generally avoids vessels. Stejneger's beaked whales may become sexually mature when they reach about 4.5 meters (14.8 feet) in length. A sexually mature female will give birth to a single calf that is about 2.2 to 2.4 meters (7.2 to 8) feet long and weighs about 80 kilograms (175 pounds). The calving season is generally between spring and autumn.

True's Beaked Whale

True’s beaked whales (Scientific name: Mesoplodon mirus) can be found in deep, warm, temperate waters of the North Atlantic Ocean as well as at least two other areas in the Southern Hemisphere, including one in the Indian Ocean. They receive their common name from Frederick W. True, a curator at the Smithsonian Institution, who described the species from an animal that stranded on a beach in North Carolina. Their range, which is mostly known from strandings, includes areas off of Nova Scotia (Canada), Bay of Biscay, Ireland, Europe, the Azores, the Canary Islands, Bermuda, Florida, and the Bahamas in the Atlantic, as well as off the coasts of Brazil, Madagascar, South Africa, New Zealand, and southern Australia. It is unknown whether this species migrates or exhibits seasonal shifts in habitat use. [Source: NOAA]

True's beaked whales have a relatively small- to medium-sized body with a moderately short beak, as well as a rounded, sloping forehead (known as a melon). They have a small, wide-based, slightly hooked dorsal fin located far down their back. Their coloration varies from gray to brown on the dorsal side with a paler ventral side. In the field, they are distinguished from Gervais’s beaked whales (which are similar in appearance) by the pale coloration across their melon and lack of a dark, defined dorsal stripe. True’s beaked whales in the Southern Hemisphere have more white coloration on their back, tailstock, and underside than those in the Northern Hemisphere. Mature males may have linear scarring covering their body from battling other males for access to females during mating. This species is difficult to observe and identify at sea due to a low profile at the surface and a small, inconspicuous blow. Few have been seen alive at sea.

True's beaked whale

Adult True's beaked whales can reach lengths of 4.7 to 5.3 meters (15.5 to 17.5 feet) and weigh from 1,000 to more than 1,360 kilograms (2,200 to more than 3,000 pounds). Females may be slightly larger than males. Mature males can be distinguished from females and juveniles by a pair of teeth visible on the tip of their lower jaw. The mouthline is typically straight or slightly curved.

When observed, True's beaked whales are often alone or in small, closely associated groups averaging five to six animals. While diving, they use suction to feed on small fish and cephalopods (such as, squid) in deep waters. This species has been known to breach and occasionally display surface active behaviors. The lifespan of this species is unknown, and very little is known about their reproduction. Females generally give birth to a single calf that is about two to 2.5 meters (6.5 to 8 feet) long and weighs about 136 kilograms (300 pounds).

Blainville's Beaked Whale

Blainville's beaked whales (Scientific name: Mesoplodon densirostris) are also known as "dense-beaked whales. They lives in tropical to temperate waters worldwide and typically found in deep, offshore waters 200 to 1,000 meters (656 to 3,281 feet) off the continental shelf and often associated with steep underwater geological structures such as banks, submarine canyons, seamounts, and continental slopes. [Source: NOAA]

Adult Blainville's beaked whales can reach lengths of approximately 4.6 to 6 meters (15 to 20 feet) and weigh 815 to 1,400 kilograms (1,800 to 2,300 pounds). Mature males can be easily distinguished from females and juveniles by a pair of large, visible, tusk-like teeth that erupt and point forward from their heavily arched lower jaw. These tusk-like teeth are sometimes covered with barnacles. Females and juveniles also have teeth, but they remain hidden beneath the gum tissue of the mouth, and their jawline is less curved. The estimated lifespan of Blainville's beaked whales is unknown. They may reach sexual maturity at about nine years of age. A sexually mature female will give birth to a single newborn calf that is about 1.9 to 2.8 meters (6 to 8.5 feet) long and weighs about 60 kilograms (130 pounds).

Blainville's beaked whales have a medium-sized, round body with a small, wide-based, slightly hooked dorsal fin located far down the animal's back. They also have a low, sloping, indistinct forehead (or melon). Their coloration varies from dark-gray to brownish and bluish. The animal’s face and underside are pale gray or white, giving it a counter-shading appearance. The skin may appear wrinkled on the dorsal area and is covered with linear and oval-shaped scars and other markings. Individuals, especially mature males, accumulate scars and scratches with age. Diatom (microscopic planktonic algae) infestation may discolor areas of the skin. [Source: NOAA]

Blainville's beaked whale

Blainville's beaked whales are usually found individually or in small social groups averaging between three and seven animals, but they have been occasionally seen in larger groups of up to 12 animals. Groups may consist of various combinations of age and sex and/or be segregated depending on age or sex. Adult populations in productive waters over the continental shelf (such as, the Bahamas) may be grouped in harems that consist of several adult females with a single adult mature male. Males commonly battle over access to females, which is probably the cause of the long linear, scars seen on individuals. [Source: NOAA]

Like other beaked whales,Blainville’s beaked whales are deep divers. Regular dives range from 20 to 45 minutes and commonly reach depths of at least 490 to 1,000 meters (1,600 to 3,300 feet), but dives of over 54 minutes and up to 1,400 meters (4,600 feet) have also been recorded. While diving, they use suction to feed on small fish and cephalopods (such as, squid) in deep water. [Source: NOAA]

The Convention on International Trade in Endangered Species (CITES) places Blainville’s beaked whales in Appendix II, which lists species not necessarily threatened with extinction now but may become so unless trade is closely controlled: They are protected throughout their range by te Marine Mammal Protection Act (MMPA): Threats include entanglement in fishing gear, ocean noise and ingestion of marine debris. They have been entangled or captured in the pelagic drift gillnet fishery off the U.S. Atlantic coast. Japanese fishing boats in the Indian Ocean (off of Seychelles and western Australia) have also incidentally taken Blainville's beaked whales. Strandings of this species in the Bahamas because of acoustic trauma have been associated with use of active sonar during naval military activities and exercises.

Longman's Beaked Whales

Longman's beaked whales (Scientific name: Indopacetus pacificus) are also known as "tropical bottlenose whales" and "Indo-Pacific beaked whales." One of the rarest and least known members of the beaked whale family, they generally live in warm, deep, pelagic waters of tropical and subtropical regions in the Indian and Pacific Oceans. Until recently, this species was only known and described from two skulls found on beaches. The first skull was found in Australia in 1882 and described by H.A. Longman — their namesake — in 1926; the second skull was discovered in Africa in 1955. In the early 2000s, genetic and morphological information were used to link these skulls with more specimens of whales that washed ashore and at-sea sightings, thereby providing a more complete description of Longman’s beaked whales as a species. [Source: NOAA]

Longman’s beaked whale

Longman’s beaked whales are larger than most other beaked whale species and have other discernible physical characteristics that make them relatively easy to identify if spotted in the wild. Little is known about the life history and ecology of this species. They live in generally warm (69.8 to 87.8° F, 21º to 31º C), deep (1,000 meters over 3,300 feet), pelagic waters of tropical and subtropical regions in the Indian and Pacific Oceans. Rare sightings have been documented in the eastern tropical Pacific Ocean. Sightings in the waters surrounding the Maldives archipelago and in the western Indian and Pacific Oceans are more frequent. In U.S. waters, this species has been sighted in the Exclusive Economic Zone around the Hawaiian Islands and in the equatorial tropical Pacific. Strandings have occurred on the coasts of East and South Africa, northern Australia, the Maldives, the Philippines, southern Japan, and Sri Lanka.

Longman's beaked whales have a large, robust body with a fairly large, hooked dorsal fin located far down their back. This species has dark, small, rounded, narrow flippers that fit into a depression on either side of the body. They have a well-defined forehead — or melon — that is almost perpendicular to their long, tube-shaped beak. A crease may distinguish the melon from the beak. As these whales grow older, the melon develops into a steeper, more bulbous shape that may hang over the beak. Like other beaked whales, they have V-shaped, paired throat creases.

Longman's beaked whales have a relatively small, low, bushy blow that is usually visible and slightly angled forward. They generally have a darker grayish, bronze, brown, or olive coloration that extends from their blowhole and eye down their back, as well as a facial band. The melon and a defined patch between their neck and abdomen are lighter in color, sometimes described as creamy or pale. The upper jaw of the beak is darker than the lower jaw, which has two conical teeth located at the tip. Adult males have visible, erupted teeth (difficult to see in the field, especially when the mouth is closed) and may have linear and oval-shaped scars (such as, bites from cookie-cutter sharks and lampreys) along their body.

Longman's beaked whales are usually found in tight groups averaging between 10 and 20 individuals but have occasionally been seen in larger groups of up to 100 animals. They sometimes associate with other marine mammals such as pilot whales, spinner dolphins, and bottlenose dolphins [link to species profiles]. Dives may last from 14 to 33 minutes, and they have been observed swimming rapidly away from survey vessels while at the surface. Their feeding behavior and prey are generally unknown, but scientists believe they are like that of other beaked whales. Beaked whales are known to dive deep to forage for their food. The analysis of stomach contents from one stranded Longman’s beaked whale implies that cephalopods (such as, squid and octopus) comprised most of the whale's diet. Little is known about the reproduction or lifespan of Longman’s beaked whales because of how infrequently they are encountered and their behavior when sighted at sea. A single newborn calf was measured at three meters (9.5 feet).

Although they face threats from entanglement in fishing gear and human-caused noise, Longman’s beaked whales in the United States are not endangered or threatened. Like all marine mammals, they are protected under the Marine Mammal Protection Act. The Convention on International Trade in Endangered Species (CITES) places them in Appendix II, which lists species not necessarily threatened with extinction now but may become so unless trade is closely controlled:

Image Source: Wikimedia Commons, NOAA

Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.

Last Updated June 2023