I was wondering whether the rules might be different for sea creatures because of hydrodynamics. Practically all fish have their eyes on the sides of their heads. It’s possible that understanding hammerhead sharks and flounders would be too hard.
Puffer fish are fish which have eyes at or near the front of their heads, but they aren’t built for chasing things down. I just found out that you can get a puffer fish to chase a laser. I don’t know what that proves. Maybe they chase relatively small slow prey.
Puffers are sometimes pelagic (ocean-going) for parts of their life cycle, but typically they hang out in reefs, brackish areas, or other near-shore zones and hunt smallish prey, “sprinting” it down and delivering a quick snap, or just teasing it out from hiding places among coral or plants. They use the same “sprint” to evade attack.
Puffers also have the ability to swivel their eyes independently, like a chameleon.
I think that the rules are different for sea creatures simply because accurate sight is usually a less useful position sense in water. In most places you can’t see far away no matter how good your eyes are, so just noticing shadows is mostly enough. Sound (including vibrations and currents) tends to be more useful there, hence echolocation and the lateral line, as is smell (see sharks). Basically, you can’t hunt much with sight, but it’s still useful to avoid being hunted.
There are some exceptions, like octopi (big eyes) and some fish with curiously complex sight (poly-chromatic, polarization-sensitive eyes) I don’t have a very good explanation for. But I’d guess they’re a bit like bats for land animals, some accident of evolution probably threw them on a tangent and they found a “local maxima” of fitness.
I was wondering whether the rules might be different for sea creatures because of hydrodynamics. Practically all fish have their eyes on the sides of their heads. It’s possible that understanding hammerhead sharks and flounders would be too hard.
Puffer fish are fish which have eyes at or near the front of their heads, but they aren’t built for chasing things down. I just found out that you can get a puffer fish to chase a laser. I don’t know what that proves. Maybe they chase relatively small slow prey.
Puffers are sometimes pelagic (ocean-going) for parts of their life cycle, but typically they hang out in reefs, brackish areas, or other near-shore zones and hunt smallish prey, “sprinting” it down and delivering a quick snap, or just teasing it out from hiding places among coral or plants. They use the same “sprint” to evade attack.
Puffers also have the ability to swivel their eyes independently, like a chameleon.
I think that the rules are different for sea creatures simply because accurate sight is usually a less useful position sense in water. In most places you can’t see far away no matter how good your eyes are, so just noticing shadows is mostly enough. Sound (including vibrations and currents) tends to be more useful there, hence echolocation and the lateral line, as is smell (see sharks). Basically, you can’t hunt much with sight, but it’s still useful to avoid being hunted.
There are some exceptions, like octopi (big eyes) and some fish with curiously complex sight (poly-chromatic, polarization-sensitive eyes) I don’t have a very good explanation for. But I’d guess they’re a bit like bats for land animals, some accident of evolution probably threw them on a tangent and they found a “local maxima” of fitness.