Mammal Species of the World
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.
Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )
- NISHIWAKI, M., T. KAMIYA. 1958. A beaked whale Mesoplodon stranded at Oiso Beach. BULL JAPANESE SOC SCI FISH, 24: 445-448.
- Nishiwaki, , KAMIYA. 1989. "Mesoplodon ginkgodens" (On-line). Accessed March 14, 2011 at http://www.bucknell.edu/msw3/browse.asp?s=y&id=14300163.
- Palacios, D. 1996. On the specimen of the ginkgo-toothed beaked whale, Mesoplodon ginkgodens, from the Galapagos Islands. Marine Mammal Science, 12: 444-446. Accessed March 14, 2011 at http://onlinelibrary.wiley.com.proxy.lib.umich.edu/doi/10.1111/j.1748-7692.1996.tb00596.x/pdf.
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.
Range length: 5.3 (high) m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently
Size in North America
Range: up to 4.8 m males; up to 4.9 m females
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.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: pelagic
- Moore, J. 1963. Recognizing certain species of beaked whales of the Pacific Ocean. AMER MIDLAND NAT, 70: 396-428.
Habitat and Ecology
These whales are presumed to be primarily squid eaters but may also take some fish.
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.
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Molluscivore )
- Culik, B. 2010. "Odontocetes - the toothed whales. Distribution, Behaviour, Migration and Threats" (On-line). CMS. Accessed April 06, 2011 at http://www.cms.int/reports/small_cetaceans/data/m_ginkgodens/m_ginkgodens.htm.
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.
- Lampetra tridentata
Photographs of distinctive bite marks on Mesoplodon ginkgodens indicate that their main predators may be sharks, especially cookiecutter sharks.
- Cookiecutter shark Isistius brasiliensis
Life History and Behavior
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.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; echolocation ; chemical
- Baumann-Pickering, S., S. Wiggins, E. Roth, M. Roch, H. Schnitzler, J. Hildebrand. 2010. Echolocation signals of a beaked whale at Palmyra Atoll. The Journal of the Acoustical Society of America, 127: 3790-3799.
No information is available.
There is no information available regarding the mating system of Mesoplodon ginkgodens.
There is no information available regarding the general reproductive behavior of Mesoplodon ginkgodens.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
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.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female); pre-weaning/fledging (Provisioning: Female); pre-independence (Provisioning: Female)
- Nishiwaki, M., T. Kasuya, K. Kureha, N. Oguro. 1972. FURTHER COMMENTS ON MESOPLODON-GINKGODENS. Scientific Reports of the Whales Research Institute Tokyo, 24: 43-56.
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.
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: data deficient
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Data Deficient
- 1994Insufficiently Known(Groombridge 1994)
This species, like other beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration (Cox et al. 2006). The use of active sonar from military vessels has been implicated in mass strandings of ginkgo-toothed beaked whales (Wang and Yang 2006; Yang et al. 2008).
Evidence from stranded individuals of several similar species indicates that they have swallowed discarded plastic items, which may eventually lead to death (e.g. Scott et al. 2001); this species may also be at risk.
Predicted impacts of global climate change on the marine environment may affect this species of whale, although the nature of impacts is unclear (Learmonth et al. 2006).
Relevance to Humans and Ecosystems
There are no known adverse effects of Mesoplodon ginkgodens on humans.
There are no known positive effects of Mesoplodon ginkgodens on humans.
IUCN Red List Category
Ginkgo-toothed beaked whale
The Ginkgo-toothed Beaked Whale (Mesoplodon ginkgodens) is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical looking species, but is notable for the males not having any scarring.
Ginkgo-toothed Beaked Whales are more robust than most mesoplodonts, but otherwise look fairly typical. Halfway through the jaw, there is a sharp curve up where the ginko leaf shaped tooth is. Unlike other species such as Blainville's Beaked Whale and Andrews' Beaked Whale, the teeth do not arch over the rostrum. The beak itself is of a moderately long length. The coloration is overall dark gray on males with light patches on the front half of the beak and around the head, and also have small white spots on the bottom of the tail, but the location may be variable. Females are a lighter gray and have countershading. Both of the genders reach 4.9 meters (16 feet) in length. They are around 2.4 meters long (8 feet) when born. The largest sizes for male and female are the following: Male: 4.8 meters Female: 4.9 meters
The size of these whales at birth are about 2 meters.
Population and distribution
This beaked whale has had less than 20 strandings off the coasts of Japan, California, the Galapagos Islands, New South Wales, New Zealand, Sri Lanka, the Maldives, and the Strait of Malacca. Its range is essentially tropical and temperate waters in the Indian and Pacific Ocean. There is no way to judge the population.
The males probably do not engage in combat and the species probably feed on squid and fish. No other information is known.
The only observations of this species while alive have come from hunters off the coasts of Japan and Taiwan, who occasionally take an individual. They are also affected by drift gillnets.
- MNZ MM002618/1, collected Pakawau, Golden Bay, New Zealand, 2004.
- Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. (2008). Mesoplodon ginkgodens. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 24 March 2009. Database entry includes a brief justification of why this species is of data deficient.
- Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN 0-12-551340-2
- Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN 0-7136-6334-0