"Easily distracted" is a flawed description - it's pretty much how it appears to parents of children with ADHD when they don't focus on something the parent wants them to, but from the perspective of a person with ADHD it's more like "no agency in directing your focus". So, no, you can certainly miss the snake or lion because all your brain resources went into analyzing patterns on a leaf instead of listening to the human that's now getting upset.

In fact, people with ADHD are usually more focused and harder to distract than other people - as long as they do something actually interesting to them.