Tri-spine Horseshoe Crab
Tachypleus tridentatus
Photo: Daiju Azuma / CC BY-SA 2.5 / Wikimedia Commons
A marine arthropod with a hard shell and sword-like tail, called a living fossil because its form has changed little since ancient times. It spawns on tidal flats along the Seto Inland Sea and in northern Kyushu. Land reclamation has reduced its habitat, and breeding sites in Kasaoka, Okayama, and Imari, Saga, are national Natural Monuments, while one in Saijo, Ehime, is a prefectural Natural Monument.
- Scientific name
- Tachypleus tridentatus
- Group
- Other invertebrates
- Prefectures
- Okayama, Ehime, Saga
- Japanese Red List (Ministry of the Environment)
- Critically Endangered / EndangeredMinistry of the Environment Red List 2020
- When to see
- June to August
- 日本語
- カブトガニ
- 简体中文
- 中国鲎
Sign in to record the animals you meet in your private journal and to post photos and comments. Browsing needs no account.
Sign inNatural Monuments related to the Tri-spine Horseshoe Crab
Where to see the Tri-spine Horseshoe Crab
Facilities whose official websites show this animal on display. Exhibits can change, so check each facility's latest information before you go.
When to see
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
In Kasaoka, Okayama, the spawning season is June to August. Paired adults approach the shore to lay eggs from about an hour before high tide on spring-tide nights. Late July to early August, when water reaches about 30°C, is considered optimal.
Exhibit sourceMap
Markers show designated habitats and breeding sites.
Loading map…
Frequently asked questions
The Tri-spine Horseshoe Crab is designated as a species without a fixed area and lives in places such as Okayama, Ehime, Saga.
You can see the Tri-spine Horseshoe Crab at Shimonoseki Marine Science Museum Kaikyokan, Kasaoka City Horseshoe Crab Museum, Shikoku Aquarium, Kujukushima Aquarium Umikirara, among others (confirmed on each facility's official website on 2026-10-15).
The Tri-spine Horseshoe Crab is mainly seen in June to August. In Kasaoka, Okayama, the spawning season is June to August. Paired adults approach the shore to lay eggs from about an hour before high tide on spring-tide nights. Late July to early August, when water reaches about 30°C, is considered optimal.
The Tri-spine Horseshoe Crab is listed as "Critically Endangered / Endangered" in the Ministry of the Environment Red List 2020 (listed as カブトガニ).
Animals related to the Tri-spine Horseshoe Crab
Animals in the same group or designated in the same area.
Community photos
Sign in to post and share photos and comments about the animals you meet.
Comments
No comments yet.