Blood scent
Version 0.24: This article may not be up to date for the latest stable release of Crawl.
Monsters with the blood scent flag have improved ability to detect players and find a way to reach them.
Blood scent gives monsters 1 extra tracking range. In addition, vampires will wake at the scent of blood, while sleeping hounds have a 66% chance of waking.
See Also
List of monsters with blood scent