Groundhogs are generally not dangerous to humans in terms of aggression or attacks, but they can pose some risks. They are known to be aggressive if cornered or trapped, biting or scratching in self-defense, and they can carry fleas, ticks, and possibly rabies, which are health concerns. More significantly, their burrowing behavior can cause serious damage to property by undermining foundations, damaging yards, gardens, and farm structures. They can also create hazards for pets, as a groundhog cornered by a dog may fight back and potentially injure the dog. Overall, groundhogs are more of a nuisance and a threat to property and pets than a direct danger to humans if left undisturbed.