Yes, cumcumber is safe for cats to eat but it’s a mad question because how many cats want to eat a cucumber? Have you ever seen a domestic cat eat a cucumber? You are going to tell me that you have but most cats are terrified of cucumbers! You know those so-called “funny cat videos” of cat owners putting a cucumber behind their cat and when their cat turns to see it they jump about 3 feet in the air because they don’t know what it is, well that’s a cat being terrified of a cucumber.
We don’t even know whether cucumbers are vegetables or fruit. They are an edible plant belonging to the gourd family and are considered a vegetable by chefs but are described as a fruit botanically. There you go. A bit of trivial pursuit information.
Domestic cats are carnivores as we all know and therefore they do not go out of their way to eat fruit or vegetables. They can’t detect the sugar in fruit which makes fruit tasty to humans. Domestic cats will eat a little bit of vegetable matter if they catch and eat mice because of the vegetable matter in a mouse’s stomach.
Google’s top pick in search results for the question as to whether domestic cats can eat cucumber is a website which takes the mickey out of the question and suggests that we make a veggie burger for our cat as long as you don’t include onions and garlic (onions and garlic are toxic to cats)! I wouldn’t make a veggie burger for your cat. I think it would be cruel actually and a completely misplaced idea. But then I would doubt that a single person on the planet has done this.
To get back to answering the question, an excellent source of information about the toxicity or non-toxicity of plants is the ASPCA website and they say that cucumber is “non-toxic to dogs, non-toxic to cats, non-toxic to horses”. There’s your answer. And please don’t put a cucumber behind your cat to frighten her to make a funny video. That’s not nice.
And don’t think you can make a veggie burger to convert your domestic cat to a vegetarian diet. That’s not nice either and is a very badly misplaced idea but I doubt whether you are thinking about it as mentioned. If you are it would be extraordinary because even the most naïve and uneducated cat owner knows that domestic cats are strict carnivores and therefore live off the flesh of animals. I’ve gone on for too long. I have to pad out the page because Google likes it. Sorry.
P.S. There is a company making vegetarian cat food and it sells because the ingredients include supplements which ensures that the diet is balanced. This is different to feeding a cat vegetables.