My cat has only ever eaten protein and fat, from meat, fish and some canned foods. Suddenly today I saw him eating watermelon. Do you think I should feed it to him?


In general, don't feed your cat fruit.

Cats are designed to be extremely carnivorous animals. Even more so than many other animals we think of as carnivorous such as dogs. So even if the particular fruit isn't toxic to them, they can't digest it very well, probably won't get much nutrition from it, and have a decent chance of getting diarrhea or vomiting from eating it. Fruits are also usually relatively high in sugar, which isn't very good for them when they're designed to eat meat. Just like humans, cats can even get diabetes if they eat too much sugar. Therefore, it's generally not recommended to give your cat fruit.

The one exception is if your cat suffers a lot from constipation, sometimes then vets will recommend giving them a little bit of pumpkin to add extra fiber to their diet.

Many fruits and vegetables may be toxic.

Experts don't actually have a full understanding of what exactly is toxic to cats, and so they tend to err on the safe side and tell people to keep away many foods that they're not even entirely sure are toxic to cats. It also may be the case that a small amount of toxic foods won't have any noticeable effect while it still is actually toxic. In other words, even if your animal has eaten these things in the past without anything bad happening, it's still better to keep foods thought to be potentially toxic away from it.

Below is a list of fruits and vegetables that may be toxic, but this list is not comprehensive.

  • Anything in the Allium genus. This includes things like onions, garlics, shallots, and so forth.
  • Grapes and raisins. Grapes are known to be toxic to dogs, and therefore, experts say to keep them away from cats too.
  • Citrus fruits like oranges or lemons. Citrus fruits may damage a cat's skin just by touching it as well.
  • Many rinds, seeds, and plant parts associated with the fruit. Seeds, including watermelon seeds, often contain cyanide which obviously is toxic.
  • Green fruits may be toxic. In particular, this applies to tomatoes.
  • Uncooked potatoes, the eyes of potatoes, and uncooked potato peels are all poisonous to cats.

About watermelon

The flesh of watermelon doesn't seem to be toxic to cats, but the seeds and potentially the rind are, and therefore you should be cautious in leaving out watermelon.

What should I do if my cat eats one of these things?

Take the item away from your cat if there's any left, and call your vet.


I’m not sure if I understand what you’re asking, since the title question about cats eating fruit is specific, but you close with the much more general question, “should I feed him?” So I’ll cover the obvious first: If you suspect that your cat is eating unusual things because he hasn’t been fed his normal food, then YES, of course you should feed your cat. Indeed, you should be feeding the cat appropriate cat food regularly as a matter of basic common sense.

Next, I’ll assume that you meant to ask, “Should I allow my cat to eat watermelon?” Cats often investigate with their mouth: by licking, gnawing on, and sometimes even eating something just to find out what it is. The species has survived for millennia and thrives everywhere from wilderness to dense urban environments. Although specific exceptions will occur, in general it’s safe to assume that oral exploration wouldn’t be such a common cat behavior if it often proved deadly. Cats have an extremely keen sense of smell, and that alone prevents them from ingesting most dangerous substances. Again, individual animals vary, and of course you shouldn’t knowingly allow—much less encourage—your pet to eat or drink questionable things. However, plants such as fruits and vegetables that are safely edible for humans are not something I’d consider questionable. The biggest concern in that case is probably pesticides, but generally speaking, produce sold for human consumption should be fine for cats to have a bite of. If you feel safe eating the watermelon, it’s almost certainly okay for kitty as well.

My cat just turned four, and has been eager to taste various vegetarian foods since she was a kitten. The oddest example was when she was about a year old, and ate nearly half of a small onion. She also enjoys bits of rice and bread, esp buttery bread like croissants. Her all-time favorite non-cat food is grapes– although not the actual fruit part. While she enjoys batting them around as toys, loves to lick the sticky residue on the bags they come in, and occasionally tries biting one; her true passion is for the stems. She comes running when I bring out a bunch of grapes, and impatiently noses in at them while I eat the fruit. As soon as some bare stems are uncovered, she starts diligently chewing them. Once I’ve finished the fruit, she takes the remaining stems in her mouth and runs of to munch; methodically crunching away until the whole bunch of stems is eaten. It seemed totally bizarre until I considered how, to her, those stems are much like the bones of small rodent. So it makes sense that she’d enjoy chewing on something that feels like a prey animal. That’s just pure speculation on my part, but it seems logical.

I only buy grapes when they’re very much on sale, so it’s not a daily or even weekly event, but whenever I do have them, she gets the stems. This has been going on for years and she’s never shown any ill effects, so I see no reason to prevent the very amusing behavior. Surely there will be some fretful cat parents who feel differently, but in my experience it’s usually safe to trust in nature & evolution; to realize that an adult cat may feel like my baby, but isn’t actually helpless & fragile like a human baby. So if she likes to chow down on grape stems, steal a bite of potato off my plate, etc., I’m okay with that.

In closing, the short answer is yes, it’s almost certainly okay for your cat to eat watermelon if he wants to. If anything, the worst outcome is some indigestion and maybe he pukes. However, as always, use common sense! If he pukes repeatedly after eating watermelon or anything else; if his behavior changes drastically (e.g., he’s extremely lethargic; stops eating, drinking, or using the litter box for more than a day); if he’s suddenly hiding or hostile for prolonged periods; basically if something’s clearly different and stays that way for an extended time, it’s time to see the veterinarian. Cats instinctively hide pain, so watching behavior is key to finding a problem. But if everything seems normal, it probably is, even if they do weird stuff like eating fruit all of a sudden. Doing bizarre stuff is what makes cats so fun, and isn’t in itself a reason for concern.

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    Experts say don't feed cats onions or grapes because these might be toxic to them. Watermelon seeds and rinds may also be toxic. – Kai May 1 '20 at 13:38

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