A bull moose appears to smile at the camera, revealing what appear to be sharp and pointy "shark teeth"! Moose of course do not have upper teeth. What’s showing in the image is a combination of lower gums and lower teeth. In other words, what your eye sees as the ‘upper teeth’ in the image are actually the bottoms of the lower teeth, and what your eye sees as the lower teeth are the lower gums that rise up between the lower teeth!