Looks like the squirrel is inspecting nuts; nuts in the SUV, that is. Mark feigns indifference in panel 4, while not bothering to “ask the hard questions” aloud for some reason. Instead, he dribbles lame sarcasm. Is that all you have, Mark? You can do better than that. So how come Cherry and Rusty weren’t invited? You want to win over Mark? The Bros should have invited Rusty along to get excited about animals!

Okay, a few interesting visual takes:

1. As was the case even with Allen, cars often look like they are standing still. Yet, Rivera makes the case for movement in panel 3 with speed lines emanating from the trees. It’s an interesting solution, but goes against logic. Normally these lines appear on the back of the moving object (the SUV) indicating motion. But it isn’t the trees that are moving. Instead, we should normally see something suggesting blurred tree images as the SUV speeds by. Nevertheless, because we read these speed lines as “movement”, they still kind of work, which is all that is necessary.
2. The “exposed interior” view in panel 2 is not original, but unusual. It is certainly more interesting than the usual car-with-dialog balloon we see in panel 1. So points for once again (finally) inserting an unusual and interesting angle into the strip. It is unfortunate that the figures in the car (save for Cricket Bro) look flat and uninvolved. A realistic representation of people in a car, no doubt, but why waste an opportunity to show something interesting?
3. I’m guessing that the purple color in panels 2-4 is meant to suggest tinted windows, something that the B&W newspaper readers will miss.