Even Though Tarsiers, One Of The Oldest Nocturnal Primates Alive Today, Were Discovered During The Eighteenth Century, Not Many People Know About The Existence Of This Tiny Creature

According to Myron Shekelle, a biology instructor and researcher at Western Washington University, this absence of the reflective layer in the tarsier’s eyes offers some insight into the evolution of primates.

He stated that tarsiers may have once been diurnal primates, which means they were active during the day, so they had no need for the reflective layer in their eyes. Somewhere along the line, they reversed course and became nocturnal again, but they had already lost their reflective layer.