Hydrophone arrays permit to localize populations of cetaceans in realtime so as to study their behaviour in a non-invasive way and to work on their conservation. The most commonly used method based on time-difference-of-arrival can be challenged by space-time methods which can locate several simultaneous sources and separate them spatially. This paper documents some results obtained qua bearing estimation of vocalizing mammals using a three-dimensional array with 4 hydrophones and various spacetime methods such as the Capon and Music estimators.