Border zone

In February 2012, I was fortunate enough to visit Pona do Ouro, which is located on the southern border of the Republic of Mozambique. And I, of course, decided to go and see how things are going with the protection of the border between two independent African states, because up to the territory of South Africa was a little more than a kilometer along the coast.
According to my assumptions, there should have been sentinel towers with formidable black submachine gunners, a barbed wire fence dividing the two neighboring states, well, at least border poles with the arms of either Mozambique or South Africa.
But there was nothing of the kind. The border was an absolutely deserted sandy beach, with waves of the Indian Ocean running into it and no one ... No security, no patrolling, go whoever you want from country to country!
But it turned out that this is only at first sight the border is not protected by anyone. Just African states were very cunning, and most importantly economical. They took an army of crabs to serve on the state border! And that, it is convenient. You do not have to pay wages, feed and dress too. And they have their own weapons! Do not believe me, well, then look at the pictures and tell me if you've ever seen crabs in such quantity? Personally me - never!

Agree, not with all this simple. This is exactly BATTLE CRABS! Here's just one question that still haunts me: which of the two states hired them? After all, I could not see the signs on them ...