I was looking at mongoose eyes in particular, but my understanding is:
- Circular (human-like) pupils simply get larger/smaller depending on light levels, no change in "shape"
- Vertical slit (cat-like) eyes get wider or narrower, from "almost a line" to "almost a circle".
- Goats, mongooses, etc. have horizontal "bar" pupils — more-or-less straight edged across the top and bottom, with rounded (semicircular?) sides.
Do horizontal bar pupils, like those of a mongoose, change size in varying light levels? If so, how does their shape change? Do they get taller or narrower? Do the top and bottom become convex or concave? Does the radius of the sides increase? Does anyone have good reference pictures or diagrams?