The art was more than static -- it was almost perfunctory. Mark's face in the third panel has appeared in hundreds of daily sequences unchanged. Sometimes Mark was expressing surprise, sometimes anger, sometimes just talking. The vague expression made it useful for reuse.
Then something happened. In 2010, Jack Allen, the assistant on the strip, took over. The stories became more dynamic -- as did the art. Wildlife was still drawn accurately (a must for this strip), but rather than looking posed (almost like taxidermy), Allen imbued it with a sense of motion.
At first, the changes were subtle. Human anatomy got better. Perspective got better. Viewing angles were more dynamic. And in time, a new Mark Trail emerged -- one I'm actually reading.
Note Allen's use of the single panel in the example below. He fills the space without cluttering it up. And there's no question that the eel is in motion. The diver's pose, plus the diving motor going off to the right, indicate that the diver's falling backwards, ambushed by the eel.
Here's another single-panel action sequence from the same story. Bad guys on Sea-Doos with machine guns might be common in action movies, but for Mark Trail, this is real innovation in story-telling!
One final example: look at that last panel. That is one dynamic panel -- and because the perspective is accurate, it really makes the machine gun look like it's coming right out of the page.
Actually, Allen does a little visual trick. Note that the machine gun is in front of the sound effect, partially obscuring it. We assume that sound effects -- not being part of the scene, are floating on the surface of the fourth wall. By placing the gun in front, it appears to be breaking through that fourth wall.