Typically Tuesday mornings involve an exhaustive search and the reading of untold numbers of abstracts to find relevant high quality papers that are not too biased one way or another. One solid source today, however, I do not have to track down, thankfully. Unfortunately the article, titled "Tracking An Ancient Killer," is not available to everyone everywhere for free, I just happened to get an email that contained it, along with some very helpful corrections to past statements and analogies made here, but it can be found online or in magazine archives given that your library or a library near you has a copy of Scientific American from 2007 or access to it online. I would recommend, if an archive is not available to you and you are interested, going directly to the magazine's site and purchasing the article.
The article, written conjointly by Raymond Rogers and David Krause, details conclusions drawn from the unearthing of several veritable bloodbaths in Madagascar; areas of ground literally littered with the dead and gnawed on by everything from carrion beetles to cannibalistic carnivores. The article paints the picture of a semiarid Madagascar that I would liken to the edges of desert in the Southwest US (that being my main personal experience with deserts of course) where the vegetation grown sparsely and watering holes are few and far between and very small if existent during times of drought.
The pools of stagnant water in Cretaceous Madagascar, evidence from the article contends, may have been toxic to the animals during the times of drought which seem to have created these congregations of death so it is little wonder that an animal like Rapetosaurus would be found covered in the remains of even Majungasaurus which had been eaten by one of its own kind. Both animals, dehydrated, come to the small watering hole to drink and either toxicity of the water, dehydration itself, or fights break out and leave dead animals. More Majungasuarus are attracted by the smell of blood and eat whatever they can, friend and prey alike, go to drink to wash it all down, and fall victim to the same toxic water. It's a fantastic and scary theory much like the one found in the death quarry discussed way back with Allosaurus, Camarasaurus, and Ceratosaurus in Utah, but that was a mud mire which trapped the animals and starved them to death rather than toxic water, cannibalism, and dehydration.