Some wild animal, probably.

I wonder whether there are any jaguars hereabout--" "Oh, if the garrison be weak and the sentries sleep it is quite possible we may take the place by a rush.

But, on the other hand, it is equally possible that Griscelli may have got wind of our intention, and--" "There it is again! Something more than a wild animal this time, Fortescue," exclaims Carmen, springing to his feet.
I follow his example; but the same instant a dozen men spring from the bushes, and before we can offer any resistance, or even draw our swords, we are borne to the ground and despite our struggles, our arms pinioned to our sides..