A surprisingly wide range of animals eat watermelon rinds, from large ruminant livestock and backyard chickens to wild raccoons, deer, and even earthworms. Watermelon rind is mostly water and fiber with modest levels of nutrients like the amino acid citrulline, making it a low-calorie, hydrating snack that many species find palatable. The answer goes well beyond the handful of animals you might expect, though, and the details matter if you are thinking about feeding rinds to livestock, tossing them to backyard pets, or wondering what raided your garden overnight.
Goats and Sheep
Goats are among the most enthusiastic consumers of watermelon rind, and researchers have studied this in some detail. When watermelon plant silage replaced up to half the alfalfa hay in goat diets, there were no significant differences in gas production, metabolizable energy, or organic matter digestibility compared to the standard diet. The study concluded that watermelon silage could serve as a viable alternative forage for goats while also reducing agricultural waste.1PLOS ONE. Chemical composition and in vitro nutritional assessment of watermelon (Citrullus lanatus) plant silage as a forage option for Murciano-Granadina goats In practical terms, goats will happily devour the entire rind and even the vine material without any apparent digestive trouble.
Sheep show a similar appetite. A study on lambs fed fresh watermelon-based diets in semi-arid feedlots found that watermelon reduced free water intake by about 64% compared to a standard hay diet, because the moisture content of the watermelon itself covered much of the lambs’ hydration needs. Total water intake actually went up, meaning the lambs stayed well hydrated and maintained normal performance and body temperature regulation.2Scientia Agricola. Succulent forages sustain lamb performance and hydration without compromising thermoregulation in semi-arid feedlots This makes watermelon rinds and flesh especially attractive as livestock feed in hot, dry regions where water itself is expensive or scarce.
Cattle
Cattle readily eat watermelon rinds and whole waste watermelons. In many watermelon-growing regions, unsold or cosmetically damaged fruit gets diverted to cattle operations rather than sent to a landfill. Researchers have tested making silage from leftover watermelon slices at various dry-matter levels and found that all groups produced usable silage, though the group dried to the highest dry-matter range had the best nutrient composition and digestibility.3Journal of the Hellenic Veterinary Medical Society. The Effect of Waste Watermelon Dry Matter Level on Silage Parameters and In Vitro Digestibility Ensiling is a practical step because raw watermelon spoils quickly in the heat. Drying or fermenting the rinds first extends the shelf life and concentrates the nutrients, making them more practical as a regular feed ingredient rather than just a seasonal treat.
Pigs
Pigs will eat watermelon rinds with gusto, but the research suggests you need to keep the proportion reasonable. In a trial where watermelon waste replaced 20%, 40%, or 60% of a standard concentrate diet, pigs on the 20% substitution had feed intake and final body weight comparable to those on the control diet. Push that substitution to 60%, however, and body weight dropped significantly, fiber digestibility fell, and feed conversion got considerably worse.4Animal Nutrition and Feed Technology. Growth Performance, Digestibility and Gut Morphology of Grower Pigs fed Diets Substituted with Watermelon Waste The takeaway for anyone raising pigs: watermelon rinds work as a supplement and a way to stretch feed costs, but they cannot replace the bulk of the diet without slowing growth. A ratio of roughly one part watermelon waste to four parts regular feed is a reasonable ceiling.
Horses
Horses can eat watermelon rind, and in some European countries it is a fairly common treat. The main practical concern is choking. Horses tend to bolt their food, and a large, tough chunk of rind can lodge in the esophagus. Cutting the rind into small, easy-to-chew pieces before offering it eliminates most of that risk. Nutritionally, watermelon rind is not going to move the needle for a horse that already gets adequate hay and grain, but it provides hydration and a bit of variety. Avoid feeding rind that has been seasoned, pickled, or treated with any preservative, since horses are more sensitive to certain additives than other livestock.
Chickens and Other Poultry
Backyard chicken keepers have long known that a halved watermelon is one of the fastest ways to get a flock’s attention on a hot day. Chickens will peck the rind down to a paper-thin shell, eating both the pink flesh and the white and green rind layers. Ducks and turkeys do the same. The high water content helps birds thermoregulate in summer, and the pecking activity itself can reduce boredom-related behaviors like feather picking. There is no formal research specifically on watermelon rind in poultry diets at commercial scale, but anecdotal and practical experience in small-flock management is extensive. If you raise chickens, rinds are among the safest kitchen scraps you can offer.
Dogs and Cats
Dogs can eat watermelon rind in small amounts, but it is not the ideal snack. The rind is tougher and more fibrous than the flesh, and dogs that swallow large chunks without chewing may experience gastrointestinal upset or, in small breeds, a mild obstruction. Cutting rind into thin strips or small cubes makes it safer. Cats, by contrast, show almost no interest in watermelon rind. As obligate carnivores, they lack the sweet-taste receptors that make fruit appealing to many other species, and the fibrous rind offers them nothing nutritionally. If your cat takes a nibble, it is not harmful, but do not expect enthusiasm.
Wild Animals That Raid Watermelon Patches
If you have ever grown watermelons in a garden, you know the list of uninvited guests. Raccoons are perhaps the most notorious watermelon thieves in North America. They use their dexterous front paws to tear open the fruit and will eat the flesh and much of the rind, often leaving behind a hollowed-out shell. Deer browse watermelon vines and will eat rinds, especially in late summer when other forage is drying out. Squirrels and groundhogs gnaw on rinds left in compost piles or gardens. Coyotes and foxes, though primarily carnivorous, are opportunistic enough to eat watermelon when they find it, particularly in arid landscapes where the moisture is valuable.
Tortoises and box turtles are enthusiastic rind eaters. Many reptile keepers use watermelon rind as an occasional treat, and wild box turtles in the southeastern United States have been observed eating melon scraps left near gardens. The high water content is especially beneficial for tortoises, which can become dehydrated in captivity if their diet is too dry. Rats and mice will also eat rinds, which is worth knowing if you compost: exposed rinds can attract rodents to an open pile.
Insects and Invertebrates
Watermelon rind is not just for vertebrates. Black soldier fly larvae, increasingly used in waste bioconversion and as a protein source for animal feed, thrive on watermelon waste. When researchers fermented watermelon waste with probiotics before feeding it to black soldier fly larvae, the larvae showed significantly increased growth, biomass yield, and nutritional content compared to those fed unfermented substrate.5PubMed. Probiotic-based fermentation of watermelon waste: Effects on bioconversion efficiency, microbial shifts, and expression profiles of black soldier fly larvae This matters commercially because black soldier fly larvae are themselves fed to poultry, fish, and pigs, creating a loop where watermelon waste becomes animal protein through an insect intermediary.
Earthworms also process watermelon rind effectively. In vermicomposting trials, watermelon peels were among five fruit and vegetable wastes tested as earthworm food. At an optimal feeding rate of about 30 grams of fresh waste per day, earthworms converted the rind into vermicompost with lower carbon content and weaker microbial activity than systems without earthworms, indicating that the worms were actively breaking down and stabilizing the material.6PubMed. Optimal growth condition of earthworms and their vermicompost features during recycling of five different fresh fruit and vegetable wastes Gardeners who vermicompost can add watermelon rind to the bin, though cutting it into smaller pieces speeds the process. Interestingly, the same study found that banana peels were harmful to the earthworms, so not all fruit waste is equally worm-friendly.
Fish
Aquaculture researchers have begun exploring watermelon rind powder as a functional ingredient in fish feed. The rinds contain fiber, minerals, and bioactive compounds that may partially replace conventional protein sources while supporting fish health and performance.7Food and Humanity. Watermelon rind powder: Composition, functional properties, and applications in aquaculture This line of research is still early, and you should not dump raw watermelon rind into a pond expecting your fish to eat it like pellets. But the dried, ground form shows enough promise that it could eventually become a standard feed additive, especially as the aquaculture industry looks for alternatives to fishmeal and soy.
What Makes Rinds Nutritionally Useful
Watermelon rind is roughly 95% water when fresh, which explains its appeal to animals in hot climates. Beyond hydration, the rind is the richest part of the fruit in citrulline, an amino acid the body uses to produce arginine, which in turn supports blood flow and other metabolic processes. On a dry-weight basis, rind contains about 24.7 milligrams of citrulline per gram, compared to about 16.7 for the flesh.8PubMed. Determination of citrulline in watermelon rind That citrulline content has led some researchers to describe the rind as an underutilized agricultural byproduct rather than true waste. For animals, the practical value is simpler: the rind is a low-cost source of moisture, some fiber, and a small amount of protein and micronutrients that can stretch more expensive feed ingredients.
Safety Concerns and Limitations
A reasonable question when feeding any novel food to animals is whether there are hidden toxins. Watermelon rind does contain low levels of anti-nutritional compounds like oxalate, phytate, tannins, and hydrogen cyanide. However, analysis of these compounds in watermelon found that all of them fell well below established toxic thresholds. For context, the hydrogen cyanide content was lower than the 10 milligrams per kilogram dry weight limit recommended by the FAO and WHO for mammals, and the oxalate and phytate levels were below the doses known to cause problems in humans or animals.9Annals of Biological Research. Evaluation of anti-nutrient contents of watermelon Citrullus lanatus In short, the rind is not toxic to mammals at any reasonable intake level.
The real limitations are practical, not toxicological. Rinds spoil fast, especially in warm weather, and moldy rind can harbor aflatoxins and other fungal toxins that are genuinely dangerous to livestock. Pesticide residue is another consideration: conventionally grown watermelons may have been sprayed, and the rind is the part most likely to carry residue. Washing the rind before feeding it to animals is a basic precaution. For livestock operations using watermelon waste at scale, ensiling or drying the material promptly after harvest keeps it safe and nutritious for weeks or months rather than days.
Size is the other concern. As mentioned for horses, large chunks of hard rind can cause choking in animals that bolt their food. This applies to dogs, goats, and even pigs. Cutting rinds into manageable pieces is a simple step that prevents a preventable problem.
Why Modern Watermelon Rinds Are Palatable at All
Wild relatives of the domesticated watermelon produce intensely bitter fruit. The bitterness comes from cucurbitacins, toxic compounds that deter most animals from eating the fruit. Genome sequencing of watermelon seeds dating back roughly 6,000 years revealed that a specific bitterness-regulating gene carried the bitter version of the allele in all wild Citrullus species and even in ancient seeds from Libya. By contrast, every domesticated watermelon sample going back to 1824, and all accessions of the wild subspecies cordophanus believed to be the closest relative of domesticated watermelon, carried the non-bitter allele.10Molecular Biology and Evolution. Genome Sequencing of up to 6,000-Year-Old Citrullus Seeds Reveals Use of a Bitter-Fleshed Species Prior to Watermelon Domestication
This matters for the animal-feeding question because it explains why so many species eat modern watermelon rinds willingly. The bitterness that once protected wild melons from being eaten has been bred out over millennia. A raccoon or a goat encountering a wild Citrullus colocynthis in the Kalahari would likely spit it out or suffer gastrointestinal distress from the cucurbitacins. The sweet, mild rind sitting in your compost bin is a product of thousands of years of human selection for palatability, and animals of all kinds are happy to take advantage of it.
Composting Rinds Versus Feeding Them
If you have more watermelon rind than any animal around you can eat, composting is the obvious alternative. Rinds break down readily in both traditional compost piles and vermicomposting systems. The high moisture content accelerates decomposition but can also waterlog a compost bin if you add too much at once. Mixing rinds with dry, carbon-rich material like shredded leaves or cardboard keeps the moisture balance right. Chopping the rind speeds things up considerably, since earthworms and microbes work from the surface inward.
For people who keep both livestock and a garden, feeding rinds to animals first and composting the manure afterward is arguably the most efficient cycle. The animal extracts calories and moisture from the rind, and the resulting manure is a better fertilizer than raw rind compost because the nutrients have been partially digested into more plant-available forms. The black soldier fly research points to an even more efficient version of this loop: watermelon waste feeds insect larvae, the larvae become high-protein animal feed, and the larval frass becomes compost. It is a tidy example of circular agriculture, and it starts with a piece of fruit most people throw away.