Mesoplodon bowdoini Andrews 1908

No information is known about predation.

This animal is very similar to many other beaked whales. Due to their lack of surface time and strandings, these whales are very poorly known.

No information is known.

Perception Channels: tactile ; chemical

M. bowdoini is protected under the 1972 Marine Mammal Protection Act(MMPA). This established an end to the hunting, harassing, capture or killing of marine mammals in US waters and by US citizens. MMPA also extended the ban on the importation of marine mammals or their products into the country.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: data deficient

There are no known adverse affects of M. bowdoini on humans.

There are no known positive affects of M. bowdoini on humans. These animals are not significant to the whaling industry.

Mesoplodon bowdoini affects the environment by feeding on squid and occasionally fish, which may affect their populations. No relationships with other marine animals are known.

Species Used as Host:

• None known

Mutualist Species:

• None known

Commensal/Parasitic Species:

• None known

Mesoplodon bowdoini feeds in deep waters primarily on squid. When squid are not available fish become a secondary source of food.

Animal Foods: fish; mollusks

Primary Diet: carnivore (Piscivore , Molluscivore )

Mesoplodon bowdoini, also known as Andrew's beaked whales, can be found in cool temperate water such as the Indo-Pacific Ocean. The waters around New Zealand and off the southern coast of Australia are home to this whale.

Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )

These animals prefer to forage at depths below the 1000 meter line. This is possibly due to the distribution of squid and other food sources not yet identified. The great depths to which these mammals travel can result in dives that last longer then 45 minutes.

Habitat Regions: temperate

Aquatic Biomes: pelagic ; coastal

No information available.

There have been very few sightings of this whale due to its spending little time on the surface. Of the roughly 35 specimens studied, the following is specific to M. bowdoini: indiviuals weigh 2.6 tons at their maximum and at birth the average length is approximately 2 meters. Females grow to an average of 4.6 m., with males growing slightly longer to 4.8 m. The color of males ranges from dark grayish-blue to black, except for the "beak", the tip of the rostrum and lower jaw, which are white in color. Females have more of an off-white beak.

Andrew's whale females or young are distinguished from other Mesoplodon species by their heads, which have a small melon and as a result, slants down dramatically from the body. Also, females and young have short, thick beaks. The dorsal fin of this species is rather small for its body size. This fin is found in the middle of the back, and it is triangular and blunt tipped.

The teeth of males are helpful in identification. Males have two teeth located in the lower jaw within a set of sockets in the middle of the beak. Females also contain these teeth, but they are not visible since they do not erupt through to the surface.

Average mass: 2359 kg.

Range length: 2 to 4.7 m.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Due to the lack of scarring in M. bowdoini investigators believe that there is no physical competition for partners. Little is known about the mating system of this species.

The only information on the reproductive system of M. bowdoini is from occasional observations of young. The calving season occurs during the summer and autumn.

Breeding season: summer and autumn

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

No specific information is available. As mammals, females nurse their young.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)

Head Shape Melon is relatively flat and defined posteriorly by an indentation at the blowhole. The beak is thick and short with a massive lower jaw that rises prominently on either side of the rostrum about halfway along its length. The mouthline is strongly arched. Coloration Adult males are dark blue-black with a grayish saddle that extends posteriorly from just behind the blowhole for about half the length of the dorsum. The leading edge of the dorsal fin may also be gray. The snout and lower jaws are white or pale gray for up to half the length of the jaw or to just past the teeth. Some individuals have a whitish patch on either side of the forehead at the base of the rostrum. The throat grooves are white or pale gray and the flipper pocket is also lighter in color. Sexually mature males of this species often exhibit scarring from antagonistic sparring. Other oval scars, attributed to the cookie cutter shark, Isistius brasilensis, are present especially in the posterior ventral area of adults.Females have a slate gray dorsum with flanks and belly pale gray to white. There is less white on the beak than in males. Size Adult body length ranges between 3.9 to 4.9 m. Recorded maximum body length for adult males and females is 4.6 m and 4.9 m, respectively. Body length at birth is 2.2 m. Most Likely Confused With: Mesoplodon densirostris Mesoplodon ginkgodens

Diagnostic features of the skull and mandible On the vertex of the dorsal skull the premaxillary bone extends forward of the nasal and frontal. Separates from Berardius and Ziphius. A sulcus (groove) running along the middle of the combined surfaces of the nasal bones so depresses their middle that it is the lateral portion of each nasal bone that reaches farthest forward on the vertex. Separates from Tasmacetus and Indopacetus. When the skull is upright and the long axis of the anterior half of the beak is horizontal, a horizontal plane transecting the summit of either maxillary prominence transects the mesethmoid bone. Separates from Hyperoodon. Tooth alveoli of mandible overlap the mandibular symphysis. Separates from Berardius, Ziphius, Tasmacetus, Indopacetus, Hyperoodon, M. grayi, M. europaeus, M. hectori, M. mirus, M. perrini, M. densirostris, M. ginkgodens, M. peruvianus, and M. stejnegeri. Basirostral groove absent or present as a shallow groove that does not extend past the prominental notch. Separates from M. layardii. The maxillary prominences rise 15 mm higher than the height of the premaxillaries where the latter passes between the former. Separates from M. bidens. In dorsal view, the right premaxilla extends slightly posterior beyond the right nasal. Separates from M. traversii. Antorbital tubercle formed by the maxilla and frontal and is underlain by the jugal and frontal. Separates from M. carlhubbsi.

Stranding Distribution Circumpolar distribution in the southern ocean waters north of the Antarctic convergence. Occurs in the southwest Pacific and Indian Ocean between 32oS and 54o30' S, and in the Atlantic Ocean between 36o and 52o S. The majority of recorded strandings have occurred in waters surrounding Australia and New Zealand.

Tooth position A single pair of teeth is positioned midway between the apex of the beak and the posterior end of the mouth. Tooth exposure Erupted teeth in adult males are covered by gum tissue, with only the tip of tooth exposed. Teeth do not erupt in females or juveniles. Tooth shape In lateral profile, the anterior margin is weakly sinusoidal (convex proximally, concave distally) and is longer than the strongly convex posterior margin. A denticle is positioned at the top of the anterior edge of the tooth. When the denticle is not excessively worn, it extends well past the antero-dorsal edge of the tooth.

The external appearance of Andrews' beaked whale is poorly known; however, its skeleton is similar to that of Hubbs' beaked whale. Adult males are all dark, except for the front half of the beak, which is white. The flattened tusks of males of this species emerge from the middle of the lower jaw on raised sockets, and protrude above the upper jaw. Can be confused with: The teeth of bulls, if seen well, will allow Andrews' beaked whale to be distinguished from most other Mesoplodon species. They are most likely to be mistaken for Blainville's beaked whale but lack the arched lower jaw.

Females reach at least 4.6 m in length and males reach 4.7 m. Length at birth is presumed to be about 2 m.

Essentially nothing is known of the biology of this species, other than the few facts that have been gleaned from stranded individuals.

No exploitation of this species is known. IUCN: Insufficiently known.

Andrews' beaked whale (Mesoplodon bowdoini), sometimes known as the deep-crest beaked whale or splay-toothed whale, is one of the least known members of a poorly known genus. The species has never been observed in the wild, and is known only from specimens washed up on beaches.

circum-global in Southern Ocean

Data Deficient (DD)