As natural habitats and food sources are replaced with man-made infrastructure and activities such as farming, threatened species face one of three choices: move, die or adapt.
Those that remain in the same areas as humans must quickly learn to compete for scarce resources and have been observed stealing crops, raiding livestock and displaying aggressive behaviour towards people.
Scientists studying such behaviour have discovered animals changing their diets to exploit cultivated crops, using man-made roads for faster journeys, and selecting the best foraging times to avoid human detection.
These fascinating adaptations can also produce interesting relationships between people and wildlife. In Guinea, chimpanzees have been observed “planting their own gardens” of cocoa in forests bordering human settlements.
The chimps ate the fruity cocoa pulp and either spat out the seeds or swallowed them whole, depositing them later in faeces.
Seedlings were distributed “extensively” throughout the chimps’ range area but the highest rates of survival were in areas where farmers intervened to stop other vegetation growing nearby. The farmers eventually collected and sold the cocoa pods.
Lead researcher Dr Kimberley Hockings, from Oxford Brookes University, UK, says: “My research generates interesting questions regarding crop ‘ownership’ related to who ‘plants’ the crop?
“It also emphasises the subtle yet complex ecological interconnections between sympatric humans and nonhuman primates in anthropogenic habitats.”
She adds that it could be used to promote human-chimpanzee coexistence in areas where cocoa is an important cash crop, increasing tolerance of wildlife by providing economic benefits.
I was shocked to find an adult male chimpanzee that had been speared to death for feeding on sugarcane
As renowned problem-solvers chimpanzees (Pan troglodytes) have proven a good case study for understanding how animals use intelligence to adapt to unprecedented changes in their habitat. But our knowledge of exactly how flexible apes are in response to such disruption remains limited.
Dr Hockings says conservation work directed at the growing number of chimpanzees that live outside of protected areas and close to people could prove vital in preserving the remaining wild populations.
“When I had my first experience of fieldwork observing wild chimpanzees in Uganda I was shocked to find an adult male chimpanzee that had been speared to death for feeding on sugarcane, despite chimpanzees being protected by law,” she says.
Since then her work has concentrated on learning more about human-chimpanzee interactions in order to improve conservation efforts.
Male chimps were also found to share stolen papaya with females, something they rarely do with wild foods, which led Dr Hockings to suggest that crop-raiding provided the males with a way to “show off” and impress potential mates.
Elephants have also been shown to employ crop-raiding strategies that avoid humans and the potential risks they pose. As cathemeral animals they are active 24 hours a day but studies have shown them to steal crops mainly at night.
Two studies have gone further, showing that elephants’ behaviour varies according to the lunar cycle and how dark the nights are. Dr Jody Gunn, from the Parks and Wildlife Commission of the Northern Territory, Australia, observed elephants at Mikumi National Park, Tanzania, and her results supported previous research carried out in Ghana.
“We suggest that elephants may balance the cost of high visibility and increased human guarding against the benefits of improved foraging when moonlight allows them to use visual senses to supplement hearing and smell.”
In Scandinavia, wolves (Canis lupus lupus) have been shown to have an “ambivalent” response to their habitats becoming dominated by human infrastructure, using roads for their own benefit but also avoiding larger roads and areas with a greater number of houses due to the presence of humans.
Author Barbara Zimmermann, from Hedmark University College, Norway, says the wolves’ adaptability may have helped their populations recover in urban areas but their use of roads could now threaten their future survival.
Despite wolves being on the endangered list in both Sweden and Norway, those killed by poachers still account for half of all wolf deaths in Scandinavia.
Ms Zimmermann says: “Roads may facilitate poaching by facilitating access to wolf tracks and by decreasing the patches between roads.”
She advocates measures to decrease human access to wolf territories if a relationship can be established between the number of roads and wolf survival rates.
Scientists agree that the adaptation of some species’ behaviour to human pressures is not an indicator that they can survive in human-dominated habitats long-term. They may become victims of retaliatory killings or crop protection methods and may also come into contact with new diseases from people and domestic animals.
Many of the solutions to wildlife’s increasing proximity to man have been aimed at reducing negative encounters between animals and humans for example beehive fences to deter elephants from entering farms in Kenya and an elephant underpass underneath a road that had limited their range, filmed for the BBC series Africa, first shown in 2013.
Dr Hockings says while understanding how animals change their behaviour in relation to human-dominated landscapes can provide new answers, historic threats to wildlife preservation – such as habitat destruction, loss of natural food sources and poaching – must not be neglected.
“By understanding the dynamic responses of wildlife to agriculture and changing habitats, we can better predict current and future adaptability of threatened species to human-driven land changes, hopefully leading to more effective conservation management and conflict mitigation,” she says.
“However, it is important to emphasise that conflict mitigation should not be considered in isolation from other factors affecting the sustainability of chimpanzee populations but as part of an integrated conservation strategy.”