He is an adult moose that is just starting to grow his antlers. He appears smaller as his neck and all is not swelled up for the rut. If you look at that 3rd pic you can see where the downward slope is where his brow tines will form. From there they will shoot upwards to form his web. I hope I get the chance to see him again in about a month then you will see a bigger difference in his antler growth. He also looks sort of mangey because of shedding his winter coat.