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Wildlife of Chichijima Island

Seabird, such as Brown Boody or Puffinini

20 kinds of breeding seabirds have been confirmed on Ogasawara so far. Numerous Brown Boodys and Wedge-tailed Shearwater inhabit Minamijima Island and Hahajima Nanzaki, and you can see them flying offshore. At the time of the nesting (November to December) the Wedge-tailed Shearwater, Puffinini such as Bonin Petrel, Audubon’s Shearwater, and Bulwer’s Petrel will fly towards the villages of Hahajima and Chichijima Islands at night. These young birds are attracted to the lights. The inhabitants of the island will protect the falling birds and release it the next morning.

The brown booby

Specific mammals · Birds

15 kinds of unique land birds have been confirmed on Ogasawara, many of which are endemic species. The Columba Janthina Nitens had been few in number once, but as a result of conservation efforts, it is now possible to see them not only in the mountains but also the settlements. In addition, there are A. f. Hahasima and Carduelis Sinica Kittlitzi (Oriental Greenfinch) which are the only birds of the village and only on Hahajima Island, B. j. Toyoshimai and Horornis Diphone Diphone which are the only birds of prey in Ogasawara. There is also Bonin Fruit Bat, the only unique mammal flying in the evening sky.

The red-headed wood pigeon

Specific insects

Ogasawara insects have evolved independently for each archipelago and island, and over 1,300 species have been confirmed so far. New species are still being discovered today. However, due to the foreign lizards, The Green Anole, ingesting insects, unique insects have been significantly reduced in number on Chichijima Island and Hahajima Island. Meanwhile, efforts are under way to protect Celastrina ogasawaraensis (Hahajima Island), Cylindera bonina (Anijima Island), dragonflies (Ototojima Island, Anijima Island, Hahajima archipelago)。Meimuna opalifera tells us the fall of Ogasawara with its cry.

Hemicordulia ogasawarensis


There are no conventional amphibians in Ogasawara only the reptiles Cryptoblepharus Boutoni and Gunther's Tropical Gecko (Minamitorishima Island) inhabit. Cryptoblepharus boutoni has a shiny brown body surface and can be seen on the side of farm roads and the forest road during the day, and on the trees. On Chichijima Island and Hahajima Island, we can see more foreign species of Green Anole. Its predatory pressure is so large as to destroy entire insect phases and there is also concern about competition of the habitat of the Ogasawara Lizard. In recent years, the Green Anole has been confirmed on Anijima Island, and countermeasures are progressing.

The green anole

Specific Terrestrial Snails

Ogasawara terrestrial snails are evolving according to the place of habitation, such as in trees, on the ground, or underground. 100 of the 106 native species recorded are unique. Especially Mandarina mandarina genus shows typical speciation by adaptive dissipation. However, due to the influence of the New Guinea flatworm, which preys on these, the terrestrial snails of Chichijima Island are on the verge of extinction. In order to prevent this planaria from diffusing to other places, we are advising people to remove mud from shoes, that may have hidden planarians, at the time of boarding, and getting on and off.


Preservation of native animals

Native animals in Ogasawara have evolved on the isolated ocean islands, so they are easily affected by external factors. Many animals decrease in number because of the invasion of exotic species brought by people. Pigeons, seabirds, and fruit bats were attacked by wild cats, and terrestrial shellfishes are eaten by planarian, black rats, and exotic ants. To protect these native animals, various efforts were made, such as capturing wild cats in the mountains, controlling pet cats, and exterminating mice with rat poison and ants with pesticides.


Whales/Sea turtles

Of the 85 species of dolphins and whales in the world, 24 species have been observed on Ogasawara. Indo-Pacific bottlenose dolphins sometimes swim with people and spinner dolphins sometimes come close to boats. Humpback whales rear their children in the sea around Ogasawara in winter, which can be seen not only on the ocean but also from the land. In addition, Ogasawara is the largest breeding site for green sea turtles in Japan. Mother turtles come on shore to lay eggs during the summer nights.

Wrought iron butterflyfish

Saltwater fish

The color of Ogasawara’s sea is a dark blue called “Bonin blue.” There are many fishes that are widely distributed in the Indian and Pacific Oceans. Since Ogasawara is far from land, there are endemic species such as Scarus obishime and Genicanthus takeuchii. The wrought iron butterflyfish is endemic to the area including the Izu Islands. Sand tiger sharks are decreasing in number throughout the world, and Ogasawara is the only breeding area in Japan. In recent years, a video showed giant squids swimming in the deep sea east of Ogasawara, which drew people’s attention.

Coral reefs


About 200 species of coral can be found in the waters surrounding Ogasawara. Unlike Okinawa, which is located at the same latitude, the seafloor topography is steep. So coral reefs have not developed, but a great number of reef-building coral, such as Acropora florida, Garaxea astreata, and Euphyllia dana can be found near the ocean islands. Also, since crown-of-thorns starfish or coral bleaching does not affect this area, we have climax coral communities that are almost lost in the Japanese marine area. You can see large-scale branch coral communities off Seihyo Beach on Chichijima Island.

Ogasawara freshwater goby

Terrestrial and aquatic animals

Many of the terrestrial/aquatic animals on Ogasawara spend their larval stages in the sea because their ancestors swam from other islands to Ogasawara. For example, some freshwater fish, such as the Ogasawara fresh water goby and Ogasawara Japanese mitten crab, stopped contacting the sea and evolved into endemic species. The Ogasawara Semisulcospira libertine, Ligia torrenticola, and Paratya boninensis are peculiar endemic species that moved from the seawater area to freshwater area. There are also fish, hermit crabs, shrimps, crabs, and water striders in Ogasawara.

Dry shrub forest on Chichijima

Sclerophyllous scrub

Sclerophyllous scrub is located on part of Chichijima Island, a very small part of the Hahajima Islands, and a large part of Anijima Island. It is comprised of trees at a height of 3 to 8 m suitable for the dry environment with thin earth, such as Distylium lepidotum, Syzygium cleyerifolium, a sole endemic coniferous tree Juniperus taxifolia, Planchonella obovate var. dubia, Schima wallichii, etc. On part of Anijima Island, trees are smaller at a height of 1 to 3 m with smaller and thicker leaves in the forest. However, the growth and regeneration of these native plants is greatly affected by exotic plants such as Casuarinaceae and Leucaena leucocephala.

Vegetation in rocky desert

Vegetation in rocky desert

On Anijima Island, the land has exposed rocks together with Sclerophyllous scrub. The vegetation can be seen on the rocky desert with precious vegetation communities comprised of Osteomeles schwerinae, Callicarpa parvifolia, as well as Fimbristylis longispica, Ischaemum ischaemoides, Aristida, Sedum japonicum subsp, and Crepidiastrum grandicollum. Also, an endemic insect, such as Cicindela bonina, can now only be found on Anijima Island. Tourists can only visit the beach area and are not allowed to go further inland on the island.

Coastal vegetation

Vegetation on the beach

The number of plants on the beach on Ogasawara is only 20 species, which are one-fifth of those on the Nansei islands. Vitex rotundifolia and Ipomoea pes-caprae cover the sandy beach, and Scaevola taccada and Heliotropium foertherianum are in the background, and tall Terminalia catappa L., Calophyllum inophyllum (or Tamana), Hibiscus tiliaceus, and Hernandiaceae can be found on the island. Tall trees were planted for protection against wind and tide, and they can be seen beside the roads along the beach. Fruits of all trees float on the water, so they reached Ogasawara with the sea current.



On ocean islands like Ogasawara, there are not any chinquapin or oak trees whose seeds spread by rolling on the ground, but the percentage of ferns whose spores spread with the wind is greater than on the continents or continental islands. Many tree ferns are observed in and around the wet forest and along mountain streams on Chichijima and Hahajima Islands, which partly characterizes the forests of Ogasawara. Cyathea mertensiana, an endemic species among tree ferns, is characterized by marks of fallen leaves on the surface of a stem that look like upside-down Japanese character “八” (eight).

Palm trees

Palms and Pandanus

On Ogasawara, two endemic species of palms, Ogasawara Chinese fan palm (or hemp palm) and Clinostigma savoryanum grow. Hemp palms grow in the bush or on the thick earth along mountain streams. Their bright green leaves and straight leaf sheaths look beautiful in the forest. Pandanus, looking like palms, is known as the “Tree of the Village” and planted along roads or picnic sites. Also, coconut palms on the seashore, yellow butterfly palms in the farm land, and bottle palms along the roads create the tropical atmosphere.

Palms and Pandanus

Preservation of native vegetation

Ogasawara has original vegetation with its endemic plants, while aggressive exotic plants or feral goats greatly affect the vegetation. Goats stamp on the plants or eat rare, endemic plants, which decreases the vegetation and causes soil runoff. So, we are now working to protect and restore native vegetation by working for the eradication of feral goats and building fences that prevent them from entering areas where precious rare plants grow. Also, invasive exotic plants, including bishop wood and Casuarinaceae, are cut down or treated with herbicides.



このページの担当は自然環境部 緑環境課 自然公園計画担当です。

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