How do you know if the deer tick fell off a dog or a human?

To determine if a deer tick fell off a dog or a human, you can consider the tick's size and the host's environment. Deer ticks, or black-legged ticks, are typically small and may show signs of feeding. If you find a tick on a dog, it may have more fur or debris attached to it than one found on a human. Additionally, ticks tend to attach to areas with less hair on humans, such as the scalp or behind the ears, while on dogs, they may attach in more hidden areas like between toes or under the collar.