Zalophus japonicus Peters, 1866:668

Japanese sea lion, Black sea lion



Taxonomy & Nomenclature

Synonym/s: Zalophus californianus japonicus Peters, 1866:668; Zalophus lobatus Jentink, 1892


Conservation Status


Last record: 1951 (Fisher & Blomberg, 2012)

IUCN RedList status: Extinct


According to the IUCN, the last reliable sighting (a colony of 50-60 individuals) occurred on Takeshima island in 1951, by two Korean coastguards. A juvenile was reportedly caught off Rebun Island, Japan in 1974 . However, this has been disputed. Other reported sightings have been dismissed on the grounds that they were probably escaped Californian Sea Lions or hoaxes. However, the IUCN factsheet for this species states there were "a total population of up to 300 in the late 1950s." So the 1974 report cannot be ruled out on the grounds that the gap between sightings is too great, nor can sightings temporally intermediate between these be either.



Sea of Japan and surrounding waters


Biology & Ecology

Very little is known of the natural history of the Japanese Sea Lion on account of it's long assumed conspecificity with the Californian Sea Lion (Z. californianus). It was assumed that they were identical in their habits and life cycle, so nobody really bothered to study them.



Possibly 8 stuffed mounted museum specimens exist (Aurioles & Trillmich, 2008). One of these is at the Tennoji Zoo, Osaka, Japan. The National Museum of Natural History, Leiden has a further three, as well as a complete skeleton and 4 skulls. A pelt and 4 skulls are currently held by the British Museum. This leaves 4 stuffed specimens unaccounted for.


Brunner (2004: 404) examined 22 skulls (21 males and 1 female) of this species, most of which are in the collection of the Historical Museum of Japanese History, Tokyo.



Above: photo taken in 1934. Source: Wikimedia Commons.



Original scientific description:

Peters, Wilhem Carl Hartwig. (1867). Eine vorläufige Übersicht der aus dem Nachlass des Baron Carl von der Decken Stammenden und auf seiner Ostafrikanischen Reise gesammelten Säugethiere und Amphibien. Monatsberichte der königlich Akademie der Wissenschaften zu Berlin. 1866 (December): 884-892.


The above citation may not be the correct one. However, it is the most likely of the two texts published by Peters in 1866 (composed in 1866 actually) that I can find. The other describes several amphibians and fish.


Other references:

Abe, H. (2002). Zalophus californianus japonicus. In. “Threatened Wildlife of Japan–Red Data Book Vol 1, Mammalia” 2nd ed, Ed by. The Ministry of Environment. pp. 46-47. (in Japanese with English abstract).

Anonymous. (1964). A preliminary list of rare mammals including those believed to be rare but concerning which detailed information is still lacking. IUCN Bulletin 11(Special Supplement): 4 pp.

Aurioles, D. and Trillmich, F. (IUCN SSC Pinniped Specialist Group). (2008). Zalophus japonicus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. ( Downloaded on 17 August 2013.

Bininda-Emonds, O.R.P., Cardillo, M., Jones, K.E., MacPhee, R.D.E., Beck, R.M.D., Grenyer, R., Price, S.A., Vos, R.A., Gittleman, J.L. & Purvis, A. 2007 The delayed rise of present-day mammals. Nature 446, 507-512.

Brunner, Sylvia. (2004). Fur seals and sea lions (Otariidae): identification of species and taxonomic review. Systematics and Biodiversity 1(3): 339-439.

Carlton, JT, Geller, JB, Reaka-Kudla, ML and Norse, EA (1999) Historical extinctions in the sea. Annual Review of Ecology and Systematics 30, 515–538.

del Monte-Luna, Pablo et al. (2023). A review of recent and future marine extinctions. Cambridge Prisms: Extinction 1: e13.

Dulvy, Nicholas K., Pinnegar, John K. and Reynolds, John D. (2009). Holocene extinctions in the sea, pp. 129-150. In: Turvey, Samuel T. (ed.). Holocene Extinctions. Oxford, UK & New York, USA: Oxford University Press. xii + 352 pp.

Fisher, Diana O. and Blomberg, Simon P. (2012). Inferring Extinction of Mammals from Sighting Records, Threats, and Biological Traits. Conservation Biology 26(1): 57-67.

Goodwin, Harry A. and Goodwin, J. M. (1973). List of mammals which have become extinct or are possibly extinct since 1600. Int. Union Conserv. Nat. Occas. Pap. 8: 1-20.

Itoo, T. (1985). New cranial materials of the Japanese sea lion, Zalophus californianus japonicus (Peters, 1866). Journal of the Mammal Society of Japan 10: 135-148.

Joslin, Paul and Maryanka, Daphne. (1968). Endangered Mammals of the World: Report on Status and Action Treatment. IUCN Publications, New Series, Supplementary Paper No. 13: 34 pp.

Kim, Eun-Bi et al. (2021). The complete mitochondrial genome of Japanese sea lion, Zalophus japonicus (Carnivora: Otariidae) analyzed using the excavated skeletal remains from Ulleungdo, South Korea. Mitochondrial DNA Part B 6(1): 3184-3185.

Lee, Sang-Rae, Kim, Yun-Bae and Lee, Tongsup. (2019). The First Molecular Evidence of Korean Zalophus japonicus (Otariidae: Sea Lions) from the Archaeological Site of Dokdo Island, Korea. Ocean Science Journal. doi: [Abstract]

Lee, T. E., Fisher, D. O., Blomberg, S. P. and Wintle, B. A. (2017). Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge. Global Change Biology 23(2): 621-634.

Lee, Yoon-Ji et al. (2022). The First Population Simulation for the Zalophus japonicus (Otariidae: Sea Lions) on Dokdo, Korea. J. Mar. Sci. Eng. 10(2): 271.

Lowry, L. (2017). Zalophus japonicus (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T41667A113089431. Downloaded on 27 June 2021.

Matsumoto, Masato and Zoo, Sappro Maruyama. (1996). [English translation of title: "The 8mm film of the Japanese Sea Lion (Zalophus californianus japonicus) taken at the former Sendai Zoo"]. Honyurui Kagaku. 36(1): 89-96.

Nakamura, K. (1992). The tragic marine mammal, Japanese sea lion, Zalophus californianus japonicus (Peters, 1866). Aquabiology 14:185-189. (in Japanese with English abstract).

Rice, D. W. (1977). A list of the marine mammals of the world. NOAA Tech. Rep. NMFS SSRF-711, 15 pp.

Rice, D. W. (1998). Marine mammals of the world: Systematics and distribution. Society for Marine Mammalogy, Special Publication 4: 1-230.

Sakahira, Fimihiro, and Niimi, Michiko. (2007). Ancient DNA Analysis of the Japanese Sea Lion (Zalophus californianus japonicus Peters, 1866): Preliminary Results Using Mitochondrial Control-Region Sequences. Zoological Science 24(1):81-85. [Abstract]

Scott, Peter (ed.). (1965). Preliminary List of Rare Mammals and Birds, pp. 155-237. In: The Launching of a New Ark. First Report of the President and Trustees of the World Wildlife Fund. An International Foundation for saving the world's wildlife and wild places 1961-1964. London: Collins.

Turvey, Samuel T. (2009). Holocene mammal extinctions, pp. 41-61. In: Turvey, Samuel T. (ed.). Holocene Extinctions. Oxford, UK & New York, USA: Oxford University Press. xii + 352 pp.

Turvey, Samuel T. and Fritz, Susanne A. (2011). The ghosts of mammals past: biological and geographical patterns of global mammalian extinction across the Holocene. Philosophical Transactions of the Royal Society B 366(1577): 2564-2576. [Supplementary Information]

Vermeij GJ. 1993. Biogeography of recently extinct marine species: implications for conservation. Conserv. Biol. 7: 391-397.

Wilson, D. E. and Reeder, D. M. (2005). Mammal species of the world: a taxonomic and geographic reference. Third edition. Baltimore, MD: John Hopkins University Press.

Wolf, J.B.W., Tautz, D. and Trillmich, F. 2007. Galapagos and Californian sea lions are separate species: genetic analysis of the genus Zalophus and its implications for conservation management. Frontiers in Zoology 4: doi:10.1186/1742-9994-4-20.

Wolff, WJ (2000) The south-eastern North Sea: Losses of vertebrate fauna during the past 2000 years. Biological Conservation 95, 209–217.


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