this is an earlier picture of mort, so the facial anatomy isn't quite right, but this is more so you can see his markings and his body type.

so so so i am going to make my characters reference sheets. when i have free time. no idea when that'll be. but i figure i should post one image that has more than just mort's head.

in lieu of a good ref, here's some quick info on him:
in terms of anatomy, he's most like an enormous canine. he has a wolfish body, hair, and teeth. his fore paws are elongated and more rodent-like, and he is able to pick things up. he has extremely long whiskers that help keep him from bashing into trees when he's barreling through the forest at full speed.
he's about 10 feet tall at the shoulders, about 20 feet long from nose to rump, and has 10 foot long tail.
he lives in a cave in a high mountain range where there is snow on the ground for much of the year, and hunts mostly elk and deer, but will go after anything that catches his fancy. Humans are one of his favorite foods, but he's lazy so he only goes looking for them a few times of the year.