TWIL #025 - Herbivores Eat Meat Too, Sometimes
Deer eat birds. Cows chew on bones. Hippos scavenge carcasses. The 'herbivore' label is more of a dietary tendency than an absolute rule.
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- #biology
- #nature
The textbook definition of a herbivore - an animal that eats only plants - turns out to be more of a generalisation than a hard rule.
Documented examples of nominally herbivorous animals consuming animal matter:
- Deer have been filmed eating live birds, small rodents, and fish, as well as gnawing on shed antlers and bones (a behaviour called osteophagy)
- Cows and sheep will chew on bones to supplement calcium and phosphorus, particularly in pastures with mineral-poor soils
- Hippos have been observed scavenging carcasses, including other hippos - hippos are physiologically herbivores but opportunistically consume meat
- Horses have been documented eating meat and fish in conditions where other food sources are scarce
- Rabbits consume their own nutrient-rich cecotropes, and have been observed eating small insects
The underlying driver is usually nutritional deficiency. When plants in an environment are low in specific minerals - phosphorus, calcium, sodium - animals that evolved to eat plants will supplement with whatever provides those nutrients, including bones, insects, and occasionally meat.
The "herbivore" classification describes the dominant dietary pattern and digestive physiology, not an absolute restriction. Most of these animals lack the carnivore adaptations (sharp canines, short digestive tracts, high stomach acid) that make meat-heavy diets efficient - but occasional opportunistic consumption appears to be more widespread than biology textbooks suggest.