In today's nature animals that can eat from trees and grass normally are four legged like a giraffe or elephant and have teeth for tough vegetation. What would the teeth be good for and would vegetation alone be enough to sustain a animal of that size. The shape of the head and only having front teeth seem that it to pull soft water vegetation in water, swallows its food mostly whole while using it teeth for sifting or catching fish. Flamingos have a similar head structure and sifts water. I imagine land was lush including the swamps would be teaming with life. It would help to know its environment.
On the other hand it would not be very fast but its size could run off anything smaller and use the tail offensively to take predictors food and eat soft dead food swallowing it whole a huge buzzard. That maybe this why it has a small head in the picture below.
