Researchers are exploring the concept of "machine metabolism" where robots consume other robots for energy. While not metabolism in the biological sense, these systems allow robots to scavenge resources and potentially self-sustain. The idea involves robots breaking down the components of other, often obsolete, robots to power themselves or build new structures. This could have significant implications for long-term autonomous missions in remote or resource-scarce environments, allowing robots to repair and maintain themselves without human intervention. The feasibility and efficiency of such systems are still under investigation, but the research points to a future where robots can be more self-reliant.