Nocturnals are animals which are active during night. Bat is a familiar nocturnal animal. They have some special features to survive in the dark like big ears, sensitive whiskers, keen nose and above-all, sharp vision to see the prey and predators in the dark.
To highlight this special capability, "Vision" Malaysian post issued a Glow-in-the-dark Miniature sheet in 2008. The eyes of Slow Loris and Tarsier glow in the dark. Thanks to Joel for sending this nice imperforated Miniature sheet for me.
You can see the glow effect below and actual sheet further down the page.