Well, i just noticed all these builds were done in 2012, and nobody blogged on it, probably because of those MOC were not attractive to other bloggers.
The builder is called Schewallex, and i suppose he is no longer active in MOC building as there was no more update after 2013. The brown mini walrus was his last project in 2013.
The whole series of build consists of those wild life we can see in Zoo, including rhino, hippo, crocs etc. I kind of liking his concept of build, it is simple and cute!
However, if really want to comment, the downside is about the joint of the animals, it needs to be at least movable or foldable.