Green Cat
This is about two aspects of green cat:
- A cat that is green (environmentally friendly) and;
- A cat with green fur or partially green fur.
Environmentally Friendly Cat

California compost. Photo by mjmonty.
I would like to write about one aspect of a cat’s environmental friendliness: composting cat litter.
I’ll be honest and say I have read conflicting ideas about this and I have conflicting views. Some environmentalists think composting cat litter is a good idea, but….there are doubts in my mind.
Some people say that composting cat litter makes a lot of sense if you have a garden. This is because you will no longer be using/buying a plastic bag to put the waste litter in and throwing it away with the rubbish (garbage). Plastic bags are not environmentally friendly. However, when you buy cat litter you can use the bag that it came in for used cat litter, at least to a substantial extent. This minimises using plastic bags. As you’re going to have to throw away the original bag anyway there is little advantage to composting litter in respect of increased use of plastic bags.
Another negative to composting cat litter is that you’ll have to use wood cat litter or some other biodegradable material. Clay based litter is not suitable. Wood cat litter is good but it is not clumping. I use it. However, a lot of people use clay based clumping litter, which is an obstacle to composting cat litter.
A further negative to composting litter (sorry about these negatives because I like the idea) is that irritating protozoan Toxoplasma gondii. A lot has been written about this parasite – too much, actually – but I struggle to find hard facts about the survivability of the toxoplasmosis oocysts in soil. We know that the oocyst that can be shed in cat’s feces is durable and can survive for about a year in soil, perhaps longer.
The people who advocate using cat litter as compost say that after 18 months of being in a compost bin, cat litter should be totally biodegraded and have a nice fertiliser-like texture. As I can’t find solid and reliable information quickly and easily on the lifespan of the Toxoplasma gondii oocyst in soil I can’t recommend composting cat litter. If I am told by a reliable scientist that the oocyst dies after a maximum of 12 months, I can reliably assume that after 18 months composting the biodegraded litter could be used to fertilise the garden. I am not told that. It is regrettable but we have to be sensible.
If you do want to compost cat litter you can layer it between sawdust, soil, or leaves. Aeration of the compost aids the process. The bacteria in a cat’s feces is a micro-organism that helps break down the cat litter to the texture of earth. The urine is OK too as it contains plant nutrients. Another factor is the general health of your cat. Urine can contain material that might not be healthy even after 18 months – I don’t know. If you don’t know, don’t do it.
Cat With Green Fur

Green Cat. It took me about 20 mins to create this. The original is here and is by Derek Bridges. It is not difficult to create a cat with green fur.
In April 1 2002, Sarah Hartwell published a long page on her well known website, Messybeast.com about the genetics of green cats. To quote..
Green is a relatively new colour in cats…None of these photos are Photoshopped….. (comment from Michael: sorry, that is not true, Sarah)

Sarah Hartwell with a green cat. Copyright Sarah Hartwell. I think my version is more realistic.
She added photographs of green cats that seem to be Photoshopped versions of white cats with low colour saturation. Sarah is very scientifically minded and it all looks real but it ain’t…no, not at all.
Miss Hartwell was probably fed up with people copying (wholesale) large chunks of her website and putting it on their sites. As a form of retaliation she thought she would embarrass these intellectual property right thieves by inventing a new sort of cat. When the copyright thieves stole the information verbatim she knew they would look foolish. It was actually an act of desperation, really, but pretty clever. Ms Hartwell used this ploy in other areas as well (miniature cats). Sometimes it was done so subtly that it was almost impossible to tell if she had invented something or whether it was true. Perhaps she went too far.
In conclusion, there are no green cats and no green cat genetics. There are melanistic cats (black cats that were not mean to be black) and blue tigers (well, there might have been some) and blue Canada lynx (rare) but as I said, green cats….no.