Typical toys for ape enclosures in European zoos are not that innovative: they consist of ropes for climbing and wafer-thin wood strips where they can wrap themselves in, so that they can hide. Tumbling around in this yellow soft mass of ribbons, they seem to enjoy the simple way of life. Should they ask for more?
Mother Bini is swinging in front. Her Son Bulan is playing at the back, Berlin Zoo. (October 23, 2018)
It’s a well-known fact that great apes get along well with computers when they get the chance. But it seems to be nonexistent on the priority list of the zoos in Europe. Maybe this is changing, starting with an initiative in theNetherlands, where a robust tablet is being built at Apenheul. The strong exterior of the tablet protects the technology inside against the wild antics of the apes!
What will their reaction be, when they finally get the opportunity to play with an app akin to Tinder, which is currently being developed specifically for orangutans? Preliminary research is required before the app is launched.
Two juvenile male orangutans take a memory test using a touchscreen embedded in a faux tree. Credit: Julia Butler (August 8, 2013)
In Apenheul orangutans participate in psychological testing to find methods of measuring their emotions and preferences. These findings can be useful when the apes are swiping photos and videos of the opposite sex.
The researchers are hoping that the project can contribute to fertile zoo dates. To emphasize this goal, the name of the project has been renamed ‘Orangutan Partner Preferences’.
For example, the ‘Tinder’ app mightbe decisive when several options present themselves: Shall we welcome that big tough orangutan man from Berlin, or can we expect the handsome ape man fromBarcelona to be more successful with this ape lady?
Behavioral psychologist Mariska Kret coordinates this research from the University of Leiden and is optimistic about the idea to submit choices to great apes. She welcomes access to touch screens, referring to American and Asian zoos where apes have years of experience playing computer games. Whether it’s drawing, puzzling or making digital music. ‘The apes are using it voluntary and enjoying it. I see it as a form of enrichment’, Kret says.
High tech orangutan in American zoo. Credit: Smithsonian NationalZoo / Flickr
The orangutans of American Milwaukee County Zoo are playing with iPads since 2011. The 31-year-old female M.J. favored images of herself and loved pictures of Tom, a male orangutan at the same zoo. She was also enthusiastic about the television series of Mr. Rogers’ Neighborhood. Tom loved the program Joy of Painting. Waving a stick in the air, he tried to follow Bob Ross’ instructions. He appreciated music from Vivaldi and Mozart, she was fond of jazz. 
Although the choices for television programmes are almost limitless, a zoo doesn’t have many options for choosing a real mate. The decision to bring couples together depends initially on genetic variation; a tactic to keep the population as healthy as possible. Simply put, ape couples should have as few family ties as possible for the strongest possible offspring. To steer propagation in the right direction, international breeding programs have beenestablished and the final decision lies with the coordinator. Therefore, the management of a zoo has little to say about the composition of a love couple.
The distance between zoos can also play a role in making the most practical choice for a partner, because transport is complicated and expensive. An orangutan from Singapore cannot simply buy an Economy Class ticket for apassenger plane. When the apes finally do meet in an enclosure, it’s still unsure if they go ‘all the way’, so that a little one might appear nine months later. The ‘Tinder’ project could help with this last obstacle.
According to Kret, there are assumptions about the attractiveness of orangutans, but they have not yet been systematically investigated. Kret: ‘You could show a female orangutan two photos, male A. and male B. If they click ona photo, they will see a video of that orangutan. It will be interesting to see which man they will choose and how long they want to watch the video. In addition, the use of Skype is also possible.’
A published dissertation on this subject is expected within four years, being worked out by behavioral psychologist Tom Roth. He started with psychological testing methods with orangutans, which focus on attention, memory andpreferences. He may also work with odors and sounds in the future, whereby odor can be transferred via blankets.
In the long term, physiological measurements could be added to the study. Thermal cameras, heart and skin measurements are amongst the possibilities thatcan be applied non-invasive, so that it doesn’t hinder the apes.
That the red-haired apes can have preferences stronger than bars, was revealed last year in Basel, Switzerland. The eleven-year-old orangutan Maja shared her stay with fourteen-year-old Budi. But she became pregnant witheighteen-year-old Vendel from a neighboring residence. The apes were separated by a fence and could only have had contact through the fence. The Swiss Zoo website states that Vendel is irresistible to every orangutan female. Of thethree orangutan men in the zoo, he is very dominant with striking cheek plates. The standard procedure of taking a DNA test, revealed to everyone’s surprise thatVendel was the father of the newborn girl Padma, instead of Budi. 
Studying the effect of cheek plates is how the ‘Tinder’ study in the Netherlands started out with, because there are strong assumptions about this. Orangutan men with high levels of testosterone develop the largest cheek platesand are said to be the most popular amongst females. But it is not yet proven whether the women literally succumb to cheek plates. In addition to findings like these, we are very curious about the first ‘Tinder’ couples in the future.