Nearly 500 dead horseshoe crabs have washed ashore at a tidal flat in Kita-Kyushu, Japan. And researchers have no idea what is killing the endangered species that dates back 200 million years. 50 to 60 dead horseshoe crabs are found annually at the Sonehigata tidal flat. But 490 have already been discovered this year. This is the largest number in the last 20 years. According to officials, the dead horseshoe crabs were healthy. But they do not say if they measured radioactivity!

In contrast, officials argued that sea level rise, decrease in places to lay eggs and lack of nutrition are the main causes for their death. Finally, the seawater temperature off Fukuoka Prefecture was 1 degree higher than usual during summer. But horseshoe crabs can be found in further southern waters as well and thus are resistant to high water temperatures. READ MORE