Good ideas..I actually never thought of adding text. Pupils are kinda scary- not sure what to think of those; they are like that in the original. Just found this..sorta fits:
"Ambush predators such as domestic cats and crocodiles have pupils that look like vertical slits. Vertical slits give predators improved depth of field and the ability to judge distances, which are essential for an animal that hunts by pouncing on its prey."
dailymail.co.uk/sciencetech/article-3189565/Predators-vertical-slits-pupils-prey-letterbox-shaped-holes.html