Wireless Sensor Networks (WSNs) is an interesting topic to the researchers because of its various applications. The applications are health monitoring and environmental monitoring, Industrial Process Monitoring, Target detection, Target tracking, Energy Efficiency, Disaster Management and Military Security Systems. The wireless medium requires highly optimized medium Access Protocols to avoid interferences. Limited resources have driven the research towards energy consumption of MAC functionalities. Two Medium Access Control (MAC) protocol performances are analyzed by using the MAC layer frame work for wireless sensor networks. In this paper, an energy efficient analysis of S-MAC and HMAC protocols for wireless sensor networks is proposed with spatial correlation concept.