Techniques are described herein for monitoring activities of organisms, including sleep. In various embodiments, logic (116) may receive, from a first sensor (106) adapted to detect activity in a first area (104), signal(s) indicating activity of an organism. Based on these signal(s), the logic may identify (504) a first time at which the organism transitions into a first state. The logic may later receive (508), from a second sensor (110, 114) adapted to detect activity in a second area (108, 112), signal(s) indicative of activity in the second area. Based on these subsequent signal(s), the logic may identify (510) a second time that is after the first time, determine (512) whether the first sensor provided signal(s) indicative of activity in the first area within another time interval preceding the second time, and selectively store (514) an indication of transition of the organism into a second state based on the determination.