finland’s lapland is home to over twenty thousand reindeer, but…

finland’s lapland is home to over twenty thousand reindeer, but with thousands killed every year due to vehicle collisions in the dark, herders now cover the animals’ antlers with a harmless fluorescent paint that glows in the light of oncoming cars, but is otherwise invisible. both female and male reindeer in lapland grow antlers, which they shed in the spring, so a new coating is reapplied in the fall. 

and as mentioned in this post, reindeer eyes have a mirrored surface behind the retina – the tapetum lucidum – which allows the animal to take in more light in the near perpetual darkness of a lapland winter, and which reflects back a light that makes the eyes already appear to shine.