Why do some domestic cats lick biodegradable bags?

Nowadays, biodegradable plastic bags are made from PLA (polylactic acid) which is derived from cornstarch. These bags are compostable. They are environmentally friendly. They’ve been around for a long time, at least since 2006 as reported on the Smithsonian website.

Cat licks a cornstarch bag
Cat licks a cornstarch bag. Photo in the public domain.
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

The manufacturing includes taking corn kernels which are milled. Dextrose is extracted from starch. Huge fermenters convert the dextrose into lactic acid which is a simple organic chemical. Industrial lactic acid is derived from many starchy sources including potatoes, beets and wheat as well as corn. It is converted to lactide. Lactide molecules are linked into long chains or polymers: polylactic acid (PLA).

Polylactic acid is a resin which is formed into containers and packaging including bags. It’s renewable and environmentally friendly.

Okay, that’s the introduction. You can see that I believe that the reason why cats lick plastic bags is because these cornstarch bags smell interesting to a cat. It is obviously a subtle smell but domestic cats have an excellent sense of smell. The first attractant for a domestic cat in terms of whether food is palatable is its smell.

RELATED: WARNING: disposable plastic gloves are a potential hazard to domestic cats

I would also hazard a guess that plastic bags made from polylactic acid tastes interesting to some cats. Let’s be clear, though, that not all cats lick plastic bags. We don’t know the percentage of cats who like to do it. I would also suggest that it is a small percentage but there’s something in the smell and taste of PLA made bags which some domestic cats enjoy.

Cornstarch itself tastes like flower or a starchy substance. That doesn’t really help me. The other ingredients for the manufacturing process may leave a smell in the PLA made bag which attracts cats.

When a cat licks these biodegradable bags, I don’t think it is an example of pica as has been suggested. It might be but I think it’s more to do with the cornstarch. But pica is an issue with some cats in which they eat non-nutritious objects such as wool which contains lanolin. It is suggested that lanolin in the wool attracts cats as it smells of their mother’s nipple! 🙂 Combined with early weaning and you have pica.

RELATED: Why does my cat eat plastic?

There may also be an issue with cats enjoying playing with plastic bags. Most often, in my experience, domestic cats do not like the sound of plastic bags when they are crumpled up. They probably remind them of a predator. In other words, domestic cats have inherited in their DNA the memory of the sound of predators such as snakes. Crinkly sounds and the sound of rockets during firework displays can frighten cats. Therefore, I don’t think plastic bags as playthings appeal in general to domestic cats.

Conclusion, the central attractant between domestic cat and plastic bags is PLA – polylactic acid. Has anyone tasted the stuff? I want someone to write a comment and tell me what a PLA plastic bag smells like. By the way cornstarch is not an allergen to cats.

I write this to the best of my knowledge but the information available on the Internet is not always entirely clear on this topic.

Useful tag. Click to see the articles: Cat behavior

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