The great raft spider or fen raft spider (Dolomedes plantarius) set free

400 of these spiders were set free by chessington zoo .the fern raft spider have brown bodies with white stripes and span of almost 3 inches and largest of britain's 660 varieties .live in wetlands and eat spiders,larvae,small fish ,tadpoles.this was done in aid of conservation to increase the size of endangered spider in the wild.