Necrophilia is known to occur in animals, with a number of confirmed observations.Kees Moeliker allegedly made one of these observations while he was sitting in his office at the Natuurmuseum Rotterdam, when he heard the distinctive thud of a bird hitting the glass facade of the building. Upon inspection, he discovered a drake (male) mallard lying dead outside the building. Next to the downed bird there was a second drake mallard standing close by. As Moeliker observed the couple, the living drake pecked at the corpse of the dead one for a few minutes then mounted the corpse and began copulating with it. The act of necrophilia lasted for about 75 minutes, in which time, according to Moeliker, the living drake took two short breaks before resuming with copulating behavior.