A statement said the experiment, which UniSA claimed was a world-first, would be of use in curbing cardiovascular disease in great apes in captivity and also provide insights brain development from an early age.

The team used a contact-free technique to obtain cardiac signals by filming subtle movements in the chimps' face or thorax, and monitoring emotional response to different stimuli.

It found that chimpanzees showed similar responses to human babies when they experienced fear, excitement, or joy, causing their heart rates to increase or decrease.

UniSA said during the study, seven chimpanzees had been filmed in captivity at the Wolfgang Koehler Primate Research Centre in Leipzig, Germany. The footage was sent to UniSA engineers and they used AI to determine heart rates.

The heart rate of a chimpanzee being measured. Courtesy UniSA

UniSA professor Javaan Chahl, a remote sensing engineer, said previous studies have relied on either sensors attached to a chimpanzee’s body or else working with an anaesthetised animal before doing basic health checks.

Apart from recording the hear rates, the researchers also also compared how heart rates changed when videos of aggressive behaviour between chimpanzees from different groups, scenes of chimpanzees eating, and nature videos, were shown to the animals.

Lead author, UniSA PhD student Danyi Wang, said: “Heart rate changes can be linked to emotional responses, mental effort, attention and focus.

A chimp receiving a food reward (i.e fruit juice) so it remains still for the camera to film its facial movements. The reading was compared with the pulse taken from its finger, which proved its accuracy. Courtesy UniSA

“Babies show emotional responses early in development, which can be observed by physiological changes that help them adapt and integrate into their environment. We observed the same in the chimpanzees we monitored.

“Their responses to viewing nature scenes could be an innate physiological response to the natural world. We know that when humans spend time in nature, or view nature-related stimuli, it has a calming effect. It appears nature has the same effect on chimpanzees, and this could be deeply rooted in our evolutionary history.”

Prof Chahl said: “This would not only complement existing efforts to understand the evolution of cognition, but it would also enable us to test populations that otherwise do not engage in cognitive tasks, such as very young or untrained primates.”

Given that heart disease is very common in captive great apes, particularly in older animals, due to age-related changes, thickening of the heart muscles and reduced elasticity, monitoring of the heart would help in early detection of abnormal heart rhythms and potential signs of cardiac disease.

“Our contact-free technique opens up new routes to study primates’ emotional and cognitive states and may also greatly enhance the health management of a wide range of animal species,” Prof Chahl added.