Orcs are commonly depicted as being green skinned, tusked, pointy eared humanoids. While the green skin part was popularized by games like Warcraft, I’m not so sure about the tusks or pointy ears. Does anyone know what the earliest depiction of orcs having pointy ears and tusks is, and why they were given those traits?
In the 1970s, Greg & Tim Hildebrandt did a series of official Tolkien calendars, published by Ballantine Books. The first was the 1976 calendar, published in 1975, which for June featured the image "Captured By Orcs" (see below). This clearly shows the orcs having tusks and pointed ears.
In the preceding 1975 calendar (published 1974), Tim Kirk has an illustration of two orcs (below), with one clearly having tusks (and fangs). However, helmets obscure the ears, making it impossible to tell if they are pointed.
As for why, it is unclear. Tolkien described them as fanged, but (AFAIR) don't mention tusks or pointed ears. However, Nordic trolls have traditionally often been portrayed as having tusks and/or pointed ears, as in the painting below by Swedish artist John Bauer (1882-1918). Since orcs are akin to trolls, that could have been the inspiration.
See also the Arthur Rackham illustrations below of trolls and goblins: Pointed ears, but no tusks.