It really looks like a bobcat to me. They have much longer tails than most people expect, and a lion's tail is way larger than you'd expect. Think rope in gym class in diameter. Even young lions. (Although young lion's tails are proportionally shorter than an adult.) The coloring looks like that of a bobcat, appears to have some spotting on the sides. You wouldn't notice the faint spots on a lion kitten in that dark light, it'd just look really dark in color. The proportions of the cat look like an adult cat. Young cougars are just like the young of anything, relatively oversized head, and relatively stocky in appearance. Young cougars especially look stocky because they appear to be all fur. This animal looks pretty sleek, another clue it's a bobcat. Cool sighting but more than likely it's a bobcat. My .02 for what it's worth.