Mammals always represent a challenge to the origami designer, due to their naturally curved and hairy forms. For my designs, I try to design mammalian models as close-back designs, having a round, curvy back and an overall 3-D feel. I'll break my own rule to add complexity, for example, antlers or stripes, but only where I feel that this change will add to the overall appearence of the model. My earlier designs do not always follow these rules, either.

Hippo
Sheep
Rabbit
Giant Panda
Horse
Bushy park stag
Woolly rhino
Highland ram
Lion
Tiger
Elk
Rhinoceros
Platypus
Cow
My ass
Deer
Giraffe
Moose
Mabel and George