2 weeks day, 2 weeks night, how would the sleeping pattern of the planet's dominant species work with a 28 'day' Day?

Question

Okay, so I have this binary planet system. The main planet a bit bigger than earth with a size appropriate moon-planet. Both are habitable and with a humanoid species that evolved there.

But, I know that the rotations of the planet are tidally locked as a result and a 'day' on the moon planet is much longer than the primary planet, about 27-29 days in earth days and a much heavier tide on both sides

On both planets, the natives are humanoid enough; requiring almost all basic things we do; oxygen, food, water, sleep etc... and a lot of vegetation— and accompanying wildlife (predator & prey).

Question:

Since the days are vastly longer on the moon-planet, how would that effect the wildlife and natives?

I'd assume 2 weeks in day and 2 weeks in night; if that's the case then It could make things easier to see.

Vegetation life would be good, the 2 weeks or so, the plant life would develop bio-luminescence (using the energy absorbed in the 2 weeks with sun) to keep itself alive.

But my primary focus is on the humanoids.

Would hibernation for 2 weeks be the more obvious choice for their physical wellbeing to deal with the long days. (I am aware humans cannot hibernate but other mammals do)

Or would they have to live 2 weeks in darkness and 2 weeks in light and use our sleeping pattern of 8 hours a sleep in a designated amount of time?

Answer 1

Sleep need is relative. Many animals don't need sleep at all, even more complex ones such as whales and dolphins.

Cetaceans can't really sleep or they will drown. So they just "shutdown" (actually, reduce or change activity) one hemisphere of their brain for some time everyday. Then they swap the "sleeping" hemisphere. During this time they just float around doing nothing intensive, but they are still awake. After that "whale rest" they'll have both hemispheres in gear again and will do whatever it is that they need to do.

Humanoids in your world that don't hibernate could do it like whales do, even if they are land dwellers.

They may also have eyes like the ogre spider:

Its eyes are able to gather available light more efficiently than the eyes of cats and owls, and are able to do this despite the lack of a tapetum lucidum; instead, each night a large area of light sensitive membrane is manufactured within the eyes, and since arachnid eyes do not have irises, it is rapidly destroyed again at dawn.

With such prolonged days and nights, this mechanism to change the way the eye works from day ti night could evolve to be even more efricient than the ogre spider's.

Answer 2

Perhaps the humanoid species has diverged into two subspecies (or modes!): one is nocturnal, and the other is diurnal. The two have a symbiotic (and perhaps interfertile) relationship. During the day-month, the diurnals manage things. During the night-month, the nocturnals take over.

This dual-benefit-ism could form a very strong part of their psyche. It would also form a rather important kind of trust between the two groups, since a group that acted selfishly against the other would essentially destroy the whole. I can hear fables or parables being told about this world-wide.

So as not to be boring about it, I would assume that each species or order (or phyla...) would have solved that problem in DIFFERENT ways. So if you don't like the sophonts being dualist, perhaps an order of "regular" animal does it this way.