Humans weren’t the only ones to develop bad habits during lockdown. According to new research, some primates in zoos became more solitary and sedentary, and others displayed more sexually and physically dominant behaviour.
The study compared the behaviour of bonobos, chimpanzees, baboons and gorillas in a zoo and safari park in 2020, when they were hidden from the gaze of humans during lockdown, with how they behaved after visitors returned.
Olive baboons performed less sexual and dominance behaviour when visitors came back than they had shown during lockdown, the researchers observed.
They also approached visitor cars more frequently than they had the ranger’s vehicle when the park was closed.
The study, published in the journal Animals, found that when visitors returned bonobos and gorillas spent less time alone and gorillas spent less time resting.
The chimpanzees that were studied ate more and engaged more with their enclosures when the zoo was open.
According to the scientists, it is difficult to state whether lockdown experiences were positive, negative or neutral for individual animals, but the chimpanzees and baboons appeared to be specifically stimulated by the return of visitors.
Similarly, bonobos and gorillas spending less time alone could be seen as positive.
But the reduction in resting behaviour in more sedentary gorillas could also suggest they were disrupted by visitors, the researchers say.
The gorillas altered the use of their enclosure, which suggested they were able to modify their behaviour to reduce potential overstimulation and manage their own experiences effectively, the research suggests.
According to the findings, while the olive baboons may have been stimulated by visitors and the presence of cars, there was a threshold after which this did not increase.
The study also reports that their increased sexual behaviour during closure may have been because they did not have the stimulation of the presence of moving vehicles.
Dr Samantha Ward, a zoo animal welfare scientist at Nottingham Trent University’s School of Animal, Rural and Environmental Sciences, said: “Primates are some of the most cognitively advanced species in zoos and their interactions with visitors are complex.
“A limitation to understanding how visitors can affect behaviour of animals in zoos and parks is that they are rarely close to the public for prolonged periods, so this provided us with a unique opportunity.”
The interactions between humans and animals, and the impacts of the presence of zoo visitors, are considered crucial in relation to animal welfare, experts suggest.
Research has shown that different species, and even individual animals, respond differently to different humans.
Dr Ellen Williams, a zoo animal welfare researcher at Harper Adams University, said: “Our study showed the varied ways in which visitors can influence the behaviour of primates in captivity.
“Behavioural changes and changes in enclosure use in the presence of visitors highlights the adaptability of zoo species to their environments.
“Provision of environments which enable animals to actively adapt in this manner is really important for their welfare.”
Behavioural data for the study was collected between April and September 2020 and from November 2020 to January 2021, spanning multiple open and closed periods during the coronavirus pandemic.
Bonobos, chimpanzees and gorillas were observed at Twycross zoo in Leicestershire, while baboons were monitored by staff at Knowsley Safari in Merseyside.