Batucada The simple definition of Batucada would be a percussion jam session, but that doesn’t begin to describe the awesome power a tight ensemble is capable of producing. Percussion is the bare bones of samba, but the larger bateria (percussion group) ensembles within the samba schools make breathtakingly complex walls of sound. The throbbing heartbeat of the surdo drum (somewhere between a bass drum and a tom-tom) underpins rattling snares, layers of hand-held percussion instruments such as agogôs (bells), ganzás (metal tubes filled with beads that you shake), tambourims (a bit like small tambourines which you hit with a split stick), and the panting, surreal shrieks and moans of the cuíca, a friction drum.