Does anyone have any suggestions why I have found, over the last two weeks, four shore crabs (at least that's what I think they are) in our London garden? Two of them were originally alive but now they are all dead. How did they get there? (The garden is not that far from the River Thames, perhaps 500 yards, but it is all built up and there are busy roads in between.) Do I have to worry about a Biblical plague? And what should I do with the bodies? So far I have left them to the flies and ants (birds do not seem to be interested and there may not have been any foxes in since they appeared) and have not removed them out of curiosity, but am I attracting rats by letting them decompose? Any suggestions gratefully received.