COSMOS MAGAZINE

How pandas  became bamboo-loving bears

Credit: Sid Balachandran

Pandas have long confounded biologists because they have a digestive system which resembles that of carnivores, yet the bear species relies mostly on bamboo – a grass – for food.

Credit: Stefan Rotter/iStock/Getty Images Plus.

Bucking evolutionary trends, giant pandas (Ailuropoda melanoleuca) are one of just a few examples of a species which turned away from its carnivorous ancestry to become almost totally herbivorous.

Other bears – such as grizzly and black bears – are well known omnivores while polar bears are almost exclusively carnivores.

Grizzly bear. Credit: Zdenek Machacek

Pandas, too, have the gastrointestinal tract of a carnivore. So why do they subsist on bamboo?

Credit: Debbie Molle

Scientists discovered that bamboo contains special molecules called miRNAs, which enter pandas' bodies and influence their gene expression.

Credit: Ningyu He

These miRNAs help regulate growth, behaviour, immunity, and even how pandas smell and taste bamboo.

Credit: Pascal Muller

Over time, these genetic changes may have helped pandas adapt to a bamboo diet, despite their carnivorous ancestry.

Credit:Elena Loshina

Credit: Vince Russell

This discovery could lead to new research on animal health, diet safety, and even disease prevention. It could also help to assess and improve the safety of plant-based foods for animals and humans. But more research is needed.