Kristyn’s Reviews > An Immense World: How Animal Senses Reveal the Hidden Realms Around Us > Status Update

“It’s ridiculous to treat these groups as monolithic when we know, from other senses like vision and smell, that even closely related animals differ in how they perceive the world.”

The structure of a reindeer's tapetum changes in the dark winter to reflect even more light. Coincidentally, this also changes the tapetum's color, and thus the color of reindeer eyes, from golden yellow in the summer to a rich blue in the winter.

It’s possible that each of these visual speeds come with a different sense of time’s passage. Through a leatherback turtle‘s eyes, the world might seem to move in time-lapse, with humans bustling about at a fly’s frenetic pace. Through a fly’s eyes, the world might seem to move in slow motion

Looking around, which is inextricable from our experience of vision, is actually an unusual activity, which animals only do when they have restricted fed visual fields and narrow acute zones.

Eye Evolution in Stages

1. Only Photoreceptors - cells that detect presence of light.
2. Photoreceptors Gain Shade - a dark pigment or some other barrier that blocks light coming in from certain angles.
3. Shaded Photoreceptors cluster into groups - can knit together info about light from different directions to product images.
4. High-Resolution - addition of focusing elements like lenses.

“These qualities - sensitivity and resolution - seesaw against each other. No eye can excel at both.”

“Eyes didn’t evolve from poor to perfect,” Nilsson emphasizes. “They evolved from performing a few simple tasks perfectly to performing many complex tasks excellently.”

“The first step to understanding another animal’s Umwelt is to understand what it uses its senses for.”