Do Primates Understand Property?

As is the tradition in many zoos and sanctuaries, we distributed Christmas boxes filled with shredded paper and some treat items to small primates at the place where I have been volunteering for many years .

"What is the point?" - will you ask - "animals, do not know the meaning of Christmas."

True.  They don't, but keepers have a duty to ensure animals in their care are busy. They must provide some enrichment to their lives in captivity and the gift boxes are an opportunity to forage for treat items. Foraging is a natural behavior in the wild. Figuring out how to unwrap and open a box provides primates with an opportunity to use their brains and hands.  It is an exciting moment.  All observe carefully as volunteers place the boxes in their enclosures.  They get excited. They know it is for them.
No sooner is the catch cage open than they each rush and grab a box. They bring it to a corner where their mates will not disturb them and start the grand ceremony of opening their gifts.
One colorful capuchin reaps the wrapping paper apart with the enthusiasm of a 5 year old human child under the Christmas tree. He utters little screams of joy as he finally opens a side of the box - but then seems disappointed that it only contains the usual shredded paper, peanuts and seeds.  He jumps over to the next platform where his friend opened another box. The two exchange places and seem pretty satisfied to get the treats out.
Another capuchin monkey leaps up in the air screaming, while he swiftly lifts a gift box and brings it to his catch cage.  He is a lot more delicate than his friend and carefully opens one side of the box without spilling anything out.  He calmly eats out the treats as his two roommates who already finished up theirs look at him.  The baboon gets slightly irritated because the box is not cooperative- harder to open than he anticipated.

I am rejoiced at their reaction to the gifts. They each individually behaved as if they knew this was a special gift - which made me wonder if primates do have a sense of ownership and property.
In the wild, this manifests around food items.  In captivity, studies have demonstrated that they understand and practice barter - giving different values to different food items (or even tokens representing food items).

I refer you to two interesting articles:
Property in Non-Human Primates - Georgia State University
and
How scientists taught monkeys the concept of money (ZMEScience.com)

And to cheer everyone up, a video from Chimp Haven.

Wishing all a great end of the year and holidays!