By analysing images of giant pandas as a big cat would see them, biologists have discovered that a black and white coat is great for hiding in a forest, both in winter and in summer
Why are giant pandas black and white? It is a question that has long stumped biologists and casual observers alike. But we may at last have a clear answer.
Tim Caro at the University of Bristol, UK, and his colleagues have previously looked at camouflage in other animals to suggest that the giant panda’s distinctive patterning helps it hide from predators – such as big cats. Now the team has strengthened the idea by modelling how pandas appear to these predators.
The group analysed 15 photos of giant pandas taken in forests in south-central China and used a computer model to analyse the images as they would appear to predatory cats and dogs.
“We don’t know what a tiger or a leopard’s eye is really like, but we do know how a [domestic] cat or dog’s eye works and so we can extrapolate from that,” says Caro.
His team found that cats and dogs would both struggle to spot a panda in a forest – particularly if the panda were some distance away. The photos were taken from between 5 and 150 metres from the panda, and included both snowy and sunny environments.
From a predator’s perspective, not only did the panda’s colours match its background, but beyond a distance of 55 metres, the panda began to lose its general outline. “We’ve seen this effect in things like moths but never a mammal,” says Caro.
He says pandas are black and white because their environments are snowy in the winter and hot in the summer. “It’s a sort of compromise pattern,” says Caro. “Some animals change the colour of their coat seasonally – say brown in summer and white in winter – but this animal doesn’t do that.”
Caro adds that his team was surprised to find that even the brown mud that often gets rubbed into a panda’s fur helps with camouflage. “When we see pandas in the zoo, they tend to be fairly clean so we don’t think of them as having three different shades,” he says.
“I’m surprised by how well pandas turn out to match the colours of their background,” says Jenny Read at Newcastle University, UK. “Understanding animal camouflage is important because it helps us understand how animals interact with one another normally and also how this might be affected by human activity or interference.”
Pandas are generally safe from predators today, says Caro, but when they had a larger population, they would have faced threats from tigers, leopards and Asiatic black bears.
Journal reference: Scientific Reports, DOI: 10.1038/s41598-021-00742-4
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