  We characterize the finiteness of Gibbs measures for geodesic flows on
negatively curved manifolds by several criteria, analogous to those proposed by
Sarig for symbolic dynamical systems over an infinite alphabet. As an
application, we recover Dal'bo-Otal-Peign{\'e} criterion of finiteness for the
Bowen-Margulis measure on geometrically finite hyperbolic manifolds, as well as
Peign{\'e}' examples of gemetrically infinite manifolds having a finite
Bowen-Margulis measure. These criteria should be useful in the future to find
more examples with finite Gibbs measures.
