Boxers are strong, mid-sized dogs that originated in Germany. Their coats are both fawn and brindle. Fawn is a yellowish-brown type of color, and the addition of dark stripes to it leads to what is commonly referred to as brindle. If you ever spot a boxer that seems to be black in color, you're probably looking at a sealed brindle specimen.
"Black" Boxers
Boxers with a primarily black appearance are few and far between, although they do exist. When boxers' classic black stripes overwhelm any fawn elements of their coats, they're often called sealed brindle boxers. While brindle coats are often fawn with darker stripes, they do appear the other way around, too -- with deep brownish basic coats and conspicuously paler streaking. Note that white markings can appear in brindle and fawn boxers alike. Not all boxers have white coloration, however. White markings on boxers typically show up on their feet, faces, stomachs and chests. When boxers have particularly sizable white markings, it gives them a predominantly white look.
Thick Stripes
The stripes on brindle boxers' coats vary in thickness. Some of them have markedly slender stripes, while others have notably broad ones. A sealed brindle boxer with a black appearance often has an abundance of thick black stripes. When these stripes are so plentiful and thick, they essentially "seal" all of the fawn components out, hence the descriptive naming. When sealed brindle boxers look black, pinpointing any fawn coloration that might be there often becomes a pretty tough task.
Black Masks
Outside of boxers with primarily black coats, dogs of this jovial, spirited and dedicated breed across the board generally have some black facial coloration. This black coloration, somewhat unsurprisingly, is usually referred to as a "mask." Although the majority of boxers have masks, not all of them do.
Other Key Coat Details
Boxers, regardless of specific coloration, have extremely short hair with a coarse texture. Their coats are also glossy. Significant brushing generally is unnecessary for dogs of the breed. It can, however, keep their coats looking shimmery and healthy. If you want to keep your boxer looking tidy as can be, brush his hair on a daily basis. Boxers tend to enjoy brushing sessions, according to Cari Meister, author of "Boxers." Brushing is also important for getting rid of lingering hairs in their coats. Boxers shed a lot in the spring and autumn months.