most people have walked to the next street and even to the next town to enjoy some fast food from the takeaway rather than eat the less exciting options in the fridge at home now it seems chimpanzees will also go out of their way in order to find their favourite snacks researchers at lincoln park zoo in chicago have found that chimpanzees are willing to walk longer distances to get their favourite food   grapes   even when they are offered another option closer to hand chimpanzees at lincoln park zoo in chicago exchanged white pvc pipes (above) for either grapes or carrots  the findings suggest that our often irrational willingness to fulfill our cravings for fast food may have origins far back in our evolutionary past dr lydia hopper, a research scientist at the lester fisher centre for the study and conservation of apes at lincoln park zoo, said she hoped to explore whether the convenience of the snack on offer may also impact how far chimpanzees are willing to travel chimpanzees have special 'words' that they use for different types of food and can even learn the calls used by strangers from foreign groups primatologists have found that a group of adult chimpanzees from a safari park in holland adapted the grunts they produced for foods like apples to match those of other chimps they lived with in edinburgh their findings are the first evidence that chimpanzees can learn calls referring to specific foods or objects many scientists have assumed that one of the defining features of human language is that objects and events can be named with different words or symbols depending on the culture the researchers, whose findings are published in the journal of current biology, watched a group of adult chimpanzees from beekse bergen safari park in the netherlands were moved to join a group of chimpanzees in edinburgh zoo by analysing the acoustic structures of the calls they produced for apples, they found that the two groups of animals had different calls for the fruit before they were put together in 2010 while the dutch chimps used high pitched grunts the edinburgh chimps used far lower and softer sounds after a year of integration, the grunt calls for apple were still different, but after three years the calls produced by the dutch chimpanzees had changed to match those produced by those from edinburgh she said: 'the chimpanzees, to a limit, were willing to travel farther to obtain the more preferred grapes 'future studies should test whether chimpanzees would be willing to exert more effort for more preferred rewards if the type of effort was different   for example, time to process the food or increased competition to negotiate' dr hopper and her colleagues, whose research is published in the journal peerj, gave a group of six captive born chimpanzees at lincoln park zoo rewards in exchange for small lengths of pvc pipe that the apes had to collect from a single location the chimps could exchange these 'tokens' at one of two locations   a close by one that gave them a carrot reward or one further away that gave them a grape in a previous study dr hopper and her team had shown that the chimps preferred grapes to the carrots over the course of 15 months the researchers changed the locations of the food to see how the chimps would react they found that over time the chimps would travel further to collect the grapes in preference over the carrots their behaviour could be seen as surprising in the context of wild chimpanzees where animals will often have to take food where they can find it dr hopper said: 'it was quite fascinating to see the developments between each of the three phases of the token exchange study 'in addition to learning about food preferences and proximity, we also observed innovative, problem solving behavior among the chimpanzees' the first chimpanzee to discover the grapes at the far location was a low status female called chuckie dr hopper said that it is possible she began foraging in the further location because it was an opportunity to avoid competition from higher status chimpanzees the chimpanzees in the study preferred grapes to less exciting carrots, much like this chimp at taronga zoo  chimpanzees, like the one above, are our closest living relatives in the animal kingdom and their behaviour can help to shed light on our evolutionary past, such as how the human diet has changed over time  she added that the findings could also help zoos improve the way they care for chimps she said: 'in captivity, primates are provisioned with food by human caretakers and so have reduced choice over the options available to them 'unlike wild primates that spend a large proportion of their waking hours foraging for food, captive primates are typically fed following a regular schedule 'this study was not only of academic interest but also created novel foraging enrichment for this group of chimpanzees and encouraged them to explore their environment to find the best possible foods'
lincoln park zoo chicago
biologists at lincoln park zoo in chicago offered chimps carrots or grapes . the apes exchanged 'tokens' made of pvc tubes for the food they wanted . the chimps preferred grapes to carrots and would walk further to get them . the apes would even go in search of grapes even if carrots were close by . scientists say it shows animals will search out favourite foods like humans 