Mesoplodon ginkgodens
ginkgo-toothed beaked whale

Ginkgo-toothed beaked whales (Mesoplodon ginkgodens) reside in tropical and temperate waters throughout the Pacific and Indian Oceans. The range of this species is known from 16 specimens that were found stranded on the coasts of Japan, Taiwan, Sri Lanka, Indonesia, Australia, Southwest California, Mexico and Ecuador. There have been no confirmed sightings of live species in open oceans; however, it is presumed that they are found in the Indian and Pacific Oceans from southern California to the southern tip of India. (NISHIWAKI and KAMIYA, 1958; Nishiwaki and KAMIYA, 1989; Palacios, 1996)

No habitat information is available for Mesoplodon ginkgodens. The habits of close relatives, Mesoplodon densirostris and Mesoplodon peruvianus, suggest that M. ginkodens prefers slightly cooler areas within the temperate/tropical zone and also upwelling regions. Upwelling regions are highly productive due to nutrient-rich bottom waters cycling to the surface. (Moore, 1963; Palacios, 1996)

Based on stranded specimens, adult males appear to be mainly dark grey, darker dorsally and slightly paler ventrally. The rostrum and lower jaw of Mesoplodon ginkgodens both have a small pale gray patch. Adult females are generally paler than males. Adults of both genders display white spots and small blade-like scars. White spots are found towards the posterior end of the ventral surface and are believed to be either from natural pigmentation or parasitism. Mesoplodon ginkgodens has a pair of distinguishing ginkgo-shaped teeth, one on each side of the lower jaw towards the middle of the beak. In males they erupt beyond the gum line, but in females they do not. This characteristic tooth is present in all males in the Mesoplodon genus. Mesoplodon ginkodens is distinguished from other Mesoplodon by the great width of its ginko-shaped tooth, which is always >100mm. Males and females reach a maximum of 5.3 meters. (Moore, 1963; Palacios, 1996)

There is no information available regarding the mating system of Mesoplodon ginkgodens. (Nishiwaki, et al., 1972)

There is no information available regarding the general reproductive behavior of Mesoplodon ginkgodens.

While no parental investment information specific to << Mesoplodon ginkgodens>> is available, as mammals, it can be assumed that females likely provide their young with milk and protection until weaning.

No information is available.

Males of all species of Mesoplodon use their enlarged teeth for fighting, which they do by swimming at each other and making contact with these teeth. Females also may be scarred, but scars are more prevalent in males. Levels of aggression differ within species and can be assessed according to the number of scars on the bodies of members of each sex. Because Mesoplodon ginkgodens exhibit the least amount of scars of any Mesoplodon, it is presumed that they are the least aggressive of all Mesoplodon species. While there is no information available regarding diving and group behavior in M. ginkgodens, there is information for their close relatives Mesoplodon stejnegeri, which live in small pods that range from 5 to 15 members and dive and surface in unison. There is no information available concerning migration in M. ginkgodens. (Loughlin and Perez, 1985; MacLeod, 2000)

There is no information available regarding home range in Mesoplodon ginkgodens.

Although there is no information ragarding communication and perception in Mesoplodon ginkgodens, studies of echolocation in numerous other Mesoplodon show that they use echolocation to navigate and find prey. It is likely that frequency-modulated pulses differ by species. Pulses probably vary according to the nature of activities being conducted. (Baumann-Pickering, et al., 2010)

Based on findings of similar species and on the nature of their teeth, Mesoplodon ginkgodens probably feeds on squid and fish. Some species specialize on one prey more than the other, but the feeding habits of M. ginkgodens are unknown. In addition to fish and squid, a small amount of crustaceans have been found in the stomachs of other Mesoplodon species. (Culik, 2010; Loughlin and Perez, 1985)

Photographs of distinctive bite marks on Mesoplodon ginkgodens indicate that their main predators may be sharks, especially cookiecutter sharks.

Mesoplodon ginkgodens feed on primarily squid and fish and in doing so, likely influence the populations of these animals. In addition, Mesoplodon ginkgodens serve as host to ocean parasites such as the lampreys. (Loughlin and Perez, 1985; Nishiwaki and KAMIYA, 1989)

There are no known positive effects of Mesoplodon ginkgodens on humans.

There are no known adverse effects of Mesoplodon ginkgodens on humans.

Because there are so few wild encounters with Mesoplodon ginkgodens, it is difficult to determine population trends to assess potential conservation needs. This species is listed as "data deficient" on the IUCN's Red List of Threatened Species, and is listed under Appendix II on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Mesoplodon ginkgodens is not considered as part of the United States Endangered Species Act.