Here's a question. Why are teeth generally so symmetrical and even? A snaggle-toothed creature with lots of gaps in its teeth really doesn't bear much evolutionary advantage or disadvantage, but the norm in the animal kingdom is pretty much a full mouth of even teeth.

We see a lot of symmetry in nature, and I think it just represents the simplest way for evolutionary efforts to manifest themselves. Beyond that though, there would seem to be a high survival value in dentition that discourages matter from being caught between them. This means more food gets successfully eaten and appropriately digested, with less decay of the enamel, and fewer teeth get broken off due to torque or pressure from the sides.

It humans symmetry of the face is deemed to be more attractive which has been shown in studies, I don't know if this also applies in the animal kingdom, or whether attractiveness is even considered by some species but it's a thought.