Okayama: World’s Only Horseshoe Crab Museum Displays Live Specimens of the Endangered Species

The Yomiuri Shimbun

13:30 JST, October 26, 2024

KASAOKA, Okayama — The world’s only museum dedicated to horseshoe crabs is located in Kasaoka, Okayama Prefecture.

The arthropods are characterized by their carapace-covered bodies and sword-like tails. Males can grow to about 50 centimeters in length and weigh about 1.5 kilograms, while females can be 60 centimeters long and weigh 3 kilograms. Their appearance has mostly not changed since the Jurassic period, about 200 million years ago — long before humans. 

They used to be widespread in the Seto Inland Sea and the northern Kyushu region, but the number of living specimens has drastically decreased due to coastal reclamation and the development of tidal flats. 

They are currently categorized as “Endangered Class I” in the Environment Ministry’s Red Data Book, and the tidal flats around the Konoshima channel in Kasaoka Bay have been designated as a breeding ground and national natural monument. 

The Kasaoka Horseshoe Crab Museum displays live specimens caught by accident in fishing nets. 

A film tracing the evolution of horseshoe crabs and other creatures is shown in the museum, with an area where visitors search for the arthropods’ replicas hidden in sand. The museum is a popular weekend destination for families.