Beans are the seeds or edible pods of plants belonging to the Fabaceae family, commonly known as legumes. These plants are cultivated globally, producing seeds that are a widespread and highly nutritious food source. The consumption of beans extends far beyond human diets, encompassing a vast array of animals from insects to large grazing mammals, making the plant a significant component in many food webs.
Small Mammals and Garden Intruders
In cultivated areas, small mammals consume bean plants and seeds. Rabbits readily consume the young, tender bean seedlings and leaves. Their presence is typically indicated by clean, slanted cuts on the stems of the plants.
Squirrels and chipmunks target the seeds, either digging up newly planted beans or stripping the mature pods from the plant. Mice and voles also consume the seeds, particularly those that are stored or recently sown. Larger herbivores like deer are significant consumers, often eating the entire plant, including the leaves, shoots, and young pods. Insects also utilize bean plants, with pests like the bean weevil feeding directly on stored seeds and aphids consuming the plant’s sap.
Large Herbivores and Domesticated Species
Domesticated livestock consume beans on a commercial scale, utilizing the plants or their byproducts as a protein-rich feed source. Cattle, goats, and sheep are regularly fed cull beans—those unfit for human consumption—or the bean plant residue. The entire plant, including stalks and leaves, can be harvested as forage or processed into silage, providing feed with higher protein and mineral content than typical grain straw.
For ruminants like cattle, beans such as faba beans provide a mid-range source of protein and starch for energy. Processed bean products are also incorporated into the diets of monogastric animals, such as pigs and poultry, though their tolerance for raw beans is lower. Large wild herbivores consume wild varieties of bean plants, taking advantage of the high nutrient density available in their natural habitats.
Nutritional Value and Digestive Considerations
Beans are widely consumed due to their nutritional profile, which includes high concentrations of protein, complex carbohydrates, and fiber. They are a valuable source of amino acids, particularly lysine, supplementing grain-based diets. However, raw beans contain anti-nutritional factors (ANFs).
These ANFs include protease inhibitors, which reduce digestive enzyme effectiveness, and lectins (phytohaemagglutinins), which interfere with nutrient absorption. Monogastric animals like pigs and poultry are sensitive to these compounds, requiring heat treatment of the beans to deactivate the ANFs before feeding. Ruminants, with their multi-chambered stomach, tolerate these compounds better, as microbial fermentation in the rumen helps neutralize some anti-nutrients.