Look. Look with your special eyes 👀 Are dik-diks the only mammal with four eyes? Nope. Those marks underneath their eyes are called preorbital glands. The glands produce a dark, sticky secretion (see the next slide for proof) that dik-diks, duikers, and some other two-hoofed animals use to mark their territory. #SpecialEyes #GlandToSeeYou #UnsolicitedDikDikPic #DikDik #sandiegozoo