In this paper we address the problem of Object Tracking in WSN. We define Mobile Object Tracking as a two stage process: 1) detecting the presence of the object in the monitoring area and 2) locating it at each stage of its progression in the area. We propose a Collaborative Tracking Algorithm named CTA. CTA is a distributed protocol that runs on Heterogeneous WSN (HWSN) which consists of two types of sensors: Motion Sensors (MS) and Camera Sensors (CS). The MS deals with the detection phase and then activates the CS based on a probabilistic threshold. In addition to the tracking algorithm, we propose a deployment strategy and study its impact on CTA. The efficiency of our proposed solution is evaluated according to simulation performed. The obtained results are compared to three existing solutions: 1) Naïve solution where only CSs are deployed always in active mode; 2) OCNS (Optimal Camera Node Selection) is cluster-based approach with a CS election and 3) EAOT, our previously proposed algorithm based on heuristic CS wake up. We observe that CTA significantly reduces the tracking cost in term of energy consumption (up to 38% of energy saved compared to other algorithms). It also performs tracking ( up to 37.5% on the tracking accuracy).