AbstractPlant‐eating behavior is one of the greatest mysteries in obligate carnivores. Despite unsuitable morphological and physiological traits for plant consumption, the presence of plants in scat or stomach contents has been reported in various carnivorous species. However, researchers’ interpretations of this subject are varied, and knowledge about it is scarce, without any multispecies studies. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 felid species using data from 213 published articles. Since the frequency of plant occurrence has not always been reported, we created two‐part models and estimated parameters in a Bayesian framework. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant‐eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant‐eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants. Plant‐eating behavior is one of the greatest mysteries in obligate carnivores. , Hirata , S. , & Kinoshita , K. ( 2021 ). Plant‐eating carnivores: Multispecies analysis on factors influencing the frequency of plant occurrence in obligate carnivores . Ecology and Evolution , 11 , 10968 – 10983 . These species are widely distributed and inhabit various environments, from the tropics to the frigid zones (Johnson, 2006 ; Kitchener et al., 2017 ). In several regions, these obligate carnivores [e.g., tigers ( Panthera tigris ) (Kapfer et al., 2011 ), snow leopards ( Panthera uncia ) (Shehzad et al., 2012 )] eat plants even though their diet is considered to be exclusively carnivorous, and despite the aforementioned morphological and physiological traits that are not suitable for plant consumption. Since obligate carnivores live in diverse habitats, we added these factors to know whether frequency of plant occurrence relates to specific habitats. Animals on islands often show unique traits due to limited habitat and resources (Foster, 1964 ); therefore, we added “Island” as a binary variable, which reflects whether the sampling site was an island or mainland including a large island with area over 10,000 km 2 . We attempted to determine the effect of the abundance of vegetation on the frequency of plant occurrence in carnivores’ scat and stomach contents through NDVI. Thus, TPB y i , N i , ψ = Bernoulli 0 | ψ if y i = NA, TPB y i , N i , ψ = Bernoulli 1 | ψ ∗ Binomial ( y i | N i , p i ) if y i ≠ NA, where y i is the number of samples that contained plant materials, N i is the sample size, and p i is the frequency of plant occurrence in record i . 2.4.1 Model 1: Variation in the frequency of plant occurrence in obligate carnivores In this model, we assumed that the extent of intraspecies variation in the frequency of plant occurrence differs between species. Thus, y i ∼ TPB ψ , N i , p i , logit ( p i ) = α j + τ i , τ i ∼ Normal 0 , θ j 2 , where α j represents the mean frequency of plant occurrence in species j , τ i represents the random effect which explains the overdispersion between records, and θ j is a hyperparameter vector with a length of the number of species (Appendix S2: Table A1). 2.4.2 Model 2: Environmental and nonenvironmental factors affecting variation in the frequency of plant consumption in obligate carnivores In this model, we explored the factors that affect the frequency of plant occurrence observed in each study. Although the result did not exclude the possibility that phylogeny shows a relationship with the frequency of plant occurrence in felids, it was likely to have little effect. 4.3 Body mass We found that body mass showed a significant negative correlation with the frequency of plant occurrence, meaning that smaller carnivore species engaged in plant‐eating behavior more frequently than larger species. The correlation was significant in Model 2_1 and Model 2_3 according to both the HDI + ROPE rule and 95% CI, but not in the model with random data imputation (Model 2_2). In humans, dietary fiber intake is known to promote digestion and bowel movements by stimulating peristalsis and mucus secretion in the digestive tract (Chutkan et al., 2012 ; El‐Salhy et al., 2017 ). Plant consumption might promote digestion or excretion of indigestible food items, which are consumed by small carnivores at a high frequency. Sugar cane‐derived fibers Although cellulose intake reduces dry matter and energy digestibility both in large (Kerr et al., 2013 ) and small felids (Edwards et al., 2001 ; Prola et al., 2010 ), smaller animals may be less affected, which could explain their increased tolerance to more frequent plant consumption. Nevertheless, this can be true whether or not plant intake has some adaptive significance for obligate carnivores, and thus, this does not negate the self‐medication hypothesis or the hair evacuation hypothesis. 5 CONCLUSION This study summarized the current knowledge about plant‐eating behavior in carnivores and investigated its relationship with various factors.

These animals have evolved digestive systems capable of handling large amounts of plant material. Herbivores can be further classified into frugivores (fruit-eaters), granivores (seed eaters), nectivores (nectar feeders), and folivores (leaf eaters). Carnivores are animals that eat other animals. The word carnivore is derived from Latin and literally means “meat eater.” Wild cats such as lions, shown in Figure 34.3a and tigers are examples of vertebrate carnivores, as are snakes and sharks, while invertebrate carnivores include sea stars, spiders, and ladybugs, shown in Figure 34.3b. Obligate carnivores are those that rely entirely on animal flesh to obtain their nutrients; examples of obligate carnivores are members of the cat family, such as lions and cheetahs. Facultative carnivores are those that also eat non-animal food in addition to animal food. Note that there is no clear line that differentiates facultative carnivores from omnivores; dogs would be considered facultative carnivores. Omnivores are animals that eat both plant- and animal-derived food. In Latin, omnivore means to eat everything.

Herbivores can be further classified into frugivores (fruit-eaters), granivores (seed eaters), nectivores (nectar feeders), and folivores (leaf eaters). Carnivores are animals that eat other animals. The word carnivore is derived from Latin and literally means “meat eater.” Wild cats such as lions, shown in Figure 25.3a and tigers are examples of vertebrate carnivores, as are snakes and sharks, while invertebrate carnivores include sea stars, spiders, and ladybugs, shown in Figure 25.3b. Obligate carnivores are those that rely entirely on animal flesh to obtain their nutrients; examples of obligate carnivores are members of the cat family, such as lions and cheetahs. Facultative carnivores are those that also eat non-animal food in addition to animal food. Note that there is no clear line that differentiates facultative carnivores from omnivores; dogs would be considered facultative carnivores. Omnivores are animals that eat both plant- and animal-derived food. In Latin, omnivore means to eat everything. Humans, bears (shown in Figure 25.4a), and chickens are example of vertebrate omnivores; invertebrate omnivores include cockroaches and crayfish (shown in Figure 25.4b).

to break down carbohydrates into simple sugars – something that obligate carnivores like cats lack. Dogs evolved the ability living alongside humans Dog food is specifically formulated food intended for consumption by dogs and other related canines. Dogs are considered to be omnivores with a carnivorous bias. They have the sharp, pointed teeth and shorter gastrointestinal tracts of carnivores, better suited for the consumption of meat than of vegetable substances, yet also have ten genes that are responsible for starch and glucose digestion, a Dog food is specifically formulated food intended for consumption by dogs and other related canines. Dogs are considered to be omnivores with a carnivorous bias. They have the sharp, pointed teeth and shorter gastrointestinal tracts of carnivores, better suited for the consumption of meat than of vegetable substances, yet also have ten genes that are responsible for starch and glucose digestion, as well as the ability to produce amylase, an enzyme that functions to break down carbohydrates into simple sugars – something that obligate carnivores like cats lack. Dogs evolved the ability living alongside humans in agricultural societies, as they managed on scrap leftovers and excrement from humans. Dogs have managed to adapt over thousands of years to survive on the meat and non-meat scraps and leftovers of human existence and thrive on a variety of foods, with studies suggesting dogs' ability to digest carbohydrates easily may be a key difference between dogs and wolves. The dog food recommendation should be based on nutrient suitability instead of dog's preferences. Pet owners should consider their dog's breed, size, age, and health condition and choose food that is appropriate for their dog's nutritional needs. In the United States alone, the dog food market was expected to reach $23.3 billion by 2022. By… Like the human practice of veganism, vegan dog foods are those formulated with the exclusion of ingredients that conta Dog food is specifically formulated food intended for consumption by dogs and other related canines. Dogs are considered to be omnivores with a carnivorous bias. They have the sharp, pointed teeth and shorter gastrointestinal tracts of carnivores, better suited for the consumption of meat than of vegetable substances, yet also have ten genes that are responsible for starch and glucose digestion, as well as the ability to produce amylase, an enzyme that functions to break down carbohydrates into simple sugars – something that obligate carnivores like cats lack. Dogs evolved the ability living alongside humans in agricultural societies, as they managed on scrap leftovers and excrement from humans. Dogs have managed to adapt over thousands of years to survive on the meat and non-meat scraps and leftovers of human existence and thrive on a variety of foods, with studies suggesting dogs' ability to digest carbohydrates easily may be a key difference between dogs and wolves. The dog food recommendation should be based on nutrient suitability instead of dog's preferences. Pet owners should consider their dog's breed, size, age, and health condition and choose food that is appropriate for their dog's nutritional needs. In the United States alone, the dog food market was expected to reach $23.3 billion by 2022. By a misguided economy dogs are given meat scraps and tallow graves; one must avoid this, because these foods make them heavy and sick; give them twice a day a soup of coarse bread made with water, fat and the bottom of the stew pot; put a half-kilogram of bread at least in each soup. In England, care to give dogs Like the human practice of veganism, vegan dog foods are those formulated with the exclusion of ingredients that contain or were processed with any part of an animal, or any animal byproduct. A 2023 systematic review found no evidence of serious impacts on animal health from vegetarian cat and dog diets; however, the authors noted that the studies suffered from issues such as selection bias, low sample size, and short feeding periods and recommended further research. The omnivorous domestic canine has evolved to metabolize carbohydrates and thrive on a diet lower in protein, and a vegan diet may be adequate if properly formulated and balanced. Popularity of this diet has grown with a corresponding increase in people practicing vegetarianism and veganism as well as with growing concerns about environmental issues such as climate change or awareness of the large environmental impacts of animal agriculture. Vegetarian dog foods are produced to either assuage a pet owner's ethical concerns or for animals with extreme allergies. Due to the exclusion of animal products and by-products, which are primary ingredients of conventional dog food, many nutrients that would otherwise be provided by animal products need to be provided by replacement, plant-based ingredients. While both animal and plant products offer a wide range of macro and micronutrients, strategic formulation of plant ingredients should be considered to meet nutritional requirements, as different nutrients are more abundant in different plant sources. Despite the large differences in ingredient sourcing, studies have demonstrated that a plant-based diet can be just as edible and palatable as animal-based diets for dogs. There are now various commercial vegetarian and vegan diets available on the market. A number of common human foods and household ingestibles are toxic to dogs, including chocolate solids (theobromine poisoning), onion and garlic (thiosulfate, alliin or allyl propyl disulfide poisoning), grapes and raisins (cause kidney failure in dogs), milk (some dogs are lactose intolerant and suffer diarrhea; goats' milk can be beneficial to dogs), mushrooms, fatty foods, rhubarb, xylitol, macadamia nuts, as well as various plants and other potentially ingested materials. A full list of poison/toxic substances can be found on the ASPCA's website.