Are the bamboo shoots eaten by giant pandas actually poisonous?

When it comes to bamboo shoot experts, the giant panda is the best. Wildlife expert George Schaller once recorded that during the bamboo shoot season, a panda spent 10 hours a day eating bamboo shoots, eating 281 pieces, nearly half of its body weight!

Although bamboo shoots are a delicacy, eating them raw is risky. Bamboo not only irritates your teeth, but also contains many secondary metabolites, even cyanide. For example, each kilogram of bamboo shoots of Chimonobambusa szechuanensis contains about 3 mg of cyanide. Cyanide can generate hydrocyanic acid, a deadly drug, under the action of glycosidase and gastric acid.

If bamboo shoots are cooked, the cyanide content will be greatly reduced, so humans can happily eat bamboo shoots. But pandas cannot eat cooked bamboo shoots. Pandas absorb 54.8 to 66.1 mg of cyanide every day, which is close to the lethal dose for humans.

In the giant panda's metabolism, most of these cyanides are converted into low-toxic thiocyanate. Animals that feed on plants generally evolve the ability to deal with plant toxins, such as rhodanese, which reduces the toxicity of cyanide. But the panda's ancestors ate meat, so their rhodanese is very weak.

Why can giant pandas detoxify? Zhu Lifeng's team from Nanjing Normal University conducted a genetic analysis of the intestinal microbes of giant pandas. The results showed that the bacteria in their intestines have many genes that can produce enzymes that decompose cyanide. The intestinal bacteria of red pandas, which also feed on bamboo, also have similar genes.

It can be seen that animals that eat bamboo adapt to bamboo from the inside out, all over their body.

The illustrations in this article are not scientific illustrations but have undergone certain artistic processing.

Comic Script: The Red Queen

Scientific review: Species Calendar Team

Painting: Chen Pupu

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