Herbivorous dinosaurs, or those that ate plants, were indeed often larger than carnivorous dinosaurs, and there are several theories as to why this is the case:
- Energy Availability: Plants are abundant and do not run away, making them a more readily available food source. However, plants provide less energy than meat, so plant-eating dinosaurs might have needed larger digestive systems to process the large quantities of plant matter needed to sustain their energy needs. This could contribute to their larger size overall.
- Growth Rates: Some research suggests that herbivorous dinosaurs might have grown at faster rates than their carnivorous counterparts, leading them to reach larger sizes. Faster growth rates could be beneficial for herbivores as reaching a larger size quickly could provide some protection against predators.
- Defensive Adaptation: Large size can be a defensive adaptation. Larger herbivorous dinosaurs would have been more difficult for predators to take down. This selective pressure could have favored the evolution of larger body sizes in plant-eating species.
- Feeding Strategy: Large size also enables a higher browsing reach for plant-eating dinosaurs. This could allow them access to food resources that smaller herbivores could not reach.
It’s important to note that while many of the largest dinosaurs were herbivores, this wasn’t universally the case, and there were also many small herbivorous dinosaur species. Similarly, while most carnivorous dinosaur species were smaller than the largest herbivores, there were still many large carnivorous species as well.