I couldn’t find any particulars about this Ethiopian hyena’s situation.
I don’t think it is a fully grown individual, and I wouldn’t be surprised if this hyena had been a pet that had been raised around dogs. Spotted hyenas are known to kill dogs, so these dogs have reason to be wary of it.
Could be a young male–they are much smaller than the females(one of the few species of mammal where this is the case). Coppinger would tell you that the hyena was “domesticating itself”, I’m sure!
scroll down this page to read a neat article about the tame hyenas in Harar, Ethiopia
http://morrisonworldnews.com/?p=20436
see also
http://hararhyenas.wordpress.com/2010/07/18/two-species-many-stories/
http://hararhyenas.wordpress.com/
Thank you so much for sending this along.
I am going to do a post on this tomorrow.