Monkeys grieve over fake robot monkey thinking it was real and had died

[PlanetJosh]

https://www.youtube.com/watch?v=vaIH5tLmC8U

I loled at this and felt disturbed at doing so. It 'dies' at 30 seconds into the video.

 

[Sonikku]

What a mean trick to play on monkeys!

Poor monkeys.

 

[John Connor]

Wow! That is amazing! I never seen animals act in this way before clearly expressing emotion. Unbelievable!

 

[SKORPI0]

Watched that episode last night, it's a 5 part series.
http://www.pbs.org/wnet/nature/spy-in-the-wild-about/14810/