Decapoda is surely one of the most important taxa, both regarding the number of species and individuals, in the macrofauna of the mangrove ecosystem (Macnae, 1968; Macintosh, 1988). For this reason, knowledge about their feeding habits and diet is of primary importance for understanding the energy flow typical of this ecosystem.In Mida Creek and Gazi Bay (Kenya) we collected and then analysed the stomach contents of about 350 crabs belonging to the most common mangrove crab species (excluding the Uca species whose micro-algal feeding habits were already known): Cardisoma carnifex, Epixanthus dentatus, Eurycarcinus natalensis, Metopograpsus oceanicus, M. thukuhar, Sesarma elongatum, S. guttatum, S. leptosoma, S. meinerti, S. ortmanni, Thalamita crenata.Species were divided into classes according to the animal/vegetable matter ratio of their stomach contents.The average stomach fullness proved to be correlated with the degree of vegetable content, being lower in the carnivorous species.Stomach analysis showed that only a few species were strictly herbivorous (mostly feeding on leaf litter) or strictly carnivorous (ambush predators of molluscs or crabs). Instead, magrove crabs seemed to be generally omnivorous, probably due to the low energy and protein content of the food commonly found and to the difficulties in catching suitable prey.For Thalamita crenata, a predator inhabiting the intertidal platform in front of the mangroves, it was also possible to analyse the feeding activity in relation to the different conditions of tide and light. Its feeding activity was higher during the day than at night, and it also seems to feed during low tide, probably catching prey during ebb tides and consuming them when it hides in its shelter
