Natural intelligence has many dimensions, and in animals, learning about the environment and making behavioral changes are some of its manifestations. In primates vision plays a critical role in learning. The underlying biological neural networks contain specialized neurons and synapses which not only sense and process the visual stimuli but also learns and adapts, with remarkable energy efficiency. Forgetting also plays an active role in learning. Mimicking the adaptive neurobiological mechanisms for seeing, learning, and forgetting can, therefore, accelerate the development of artificial intelligence (AI) and bridge the massive energy gap that exists between AI and biological intelligence. Here we demonstrate a bio-inspired machine vision based on large area grown monolayer 2D phototransistor array integrated with analog, non-volatile, and programmable memory gate-stack that not only enables direct learning, and unsupervised relearning from the visual stimuli but also offers learning adaptability under photopic (bright-light), scotopic (low-light), as well as noisy illumination conditions at miniscule energy expenditure. In short, our “all-in-one” hardware vision platform combines “sensing”, “computing” and “storage” not only to overcome the von Neumann bottleneck of conventional complementary metal oxide semiconductor (CMOS) technology but also to eliminate the need for peripheral circuits and sensors.