Short version: they looked a lot more like 
than 
. Most accounts of Vikings that are contemporary of the centuries where shield-Danes and spear-Danes went "a-Viking" describe distinctly hygenic people that bathed and took care of their hair (and wore it long).
EDIT: I thought I could have a little fun with a very loosely associated Beowulf reference to Danes (and even more loose associations with Geats therein too) but I got the 
experience for doing so. 
They didn't have Hitler Youth fades with lazy and sloppy beard fusions. Period. Full stop. Stop doing that. Looking right the fuck at you too, P R E S T I G E T V. 
my people come from peat bogs. we glimpsed the retreating glaciers leaving depressions, filling with detritus and rain. we trembled with excitement to eat the sour muds. the gods cursed the hairs from our heads and sent them fleeing to our backs and asses, so we would be forever recognized for our atavistic tastes.
our banners are tattered rags.
our words are "We do not bathe."
we were here before you.
we will be here long after you have gone. with your wheels and your televisions and your detergents.