Imagine humans as predominantly nocturnal, save the occasional day lark. They have eyes like strepsirrhine primates that grant improved low-light vision but inferior day-vision. For the purposes of this question let's say that nocturnal humans see as well at night as diurnal humans do at day, and vice versa for day. They receive all sunlight-borne health benefits from a source that is irrelevant to this question. All other elements of physiology are equal to diurnal humans, and the setting is Earth.
Which animals do nocturnal humans favor as livestock? As part of a thought experiment where I justify nocturnal humans achieving civilization akin to diurnal humans, I am fleshing out aspects of animal husbandry. For reasons explained in my research below, I believe nocturnal humans will favor a similar suite of animals that we diurnal humans are familiar with, but only if certain bottlenecks can be overcome. Barring that, nocturnal humans may be much less masterful at animal husbandry, but that is beyond the scope of this question.
My research:
It's important to note that I am framing my research around a personal thought experiment where I justify nocturnal humans achieving civilization like ours. Answers to this question need not conform to those guidelines, that is just how I chose to orient my research.
Lacking deep insight into the spirit of the typical rancher or livestock, I'll have to make some assumptions. Hopefully others can enlighten me in this area where I am lacking.
My searches for large, meaty, nocturnal animals that could fulfill the role of cows, pigs, sheep and other livestock staples have proven mostly fruitless (meatless?). I believe it would be important that livestock be active and energetic at the same time ranchers are awake and working with them, makes the whole job of ranching a bit easier if the livestock move when you need them to move. But that exposes an interesting conundrum: it's a lot harder to work with livestock who can't see well in the lighting conditions you want to work with them in. I am guessing it would be exceedingly difficult to try and move a herd of virtually blind livestock.
I am far beyond my comfort zone as I make this supposition, but it seems like it would be easier to selectively breed for night-time activity than it would be to selectively breed for low-light vision, I assume the latter is a more complex series of mutations. But blindness at night is a massive hurdle that would limit the effective work which could be done by a rancher with livestock: they can't travel meaningful distances to fresh food, they're more vulnerable to night-time predators, more likely to hurt themselves on an unseen danger, and less able to understand the instructions of the rancher. As a result, I imagine that nocturnal humans would have a severely diminished capacity for animal husbandry unless low-light vision can be bred for, or there are suitable animals for this use case that I am unaware of.
Some animals that may make for appropriate nocturnal livestock:
- Elephants have low sleep times, with an average of only 2 hours, according to [Wikipedia][2]. While it is almost obscene for me to imagine such intelligent creatures in the trappings of, say, our modern cattle industry, I'm sure our nocturnal humans have a less sentimental view of things. They have some relevant qualities, lots of meat for one, and to the best of my (laypersons) understanding they have slightly improved low-light vision.
- Nocturnal marsupials like Tasmanian devils and possums. They're rather small and mean-looking, and certainly not very appetizing to my taste, but again, nocturnal humans likely think different. Several thousand generations of selective breeding could attending to those issues as well.
I am dubious about the likelihood of either of the above propositions attaining the international fame of the cow. Elephants seem like they would be troublesome to keep and hard to slaughter, and marsupials are small and not terribly common.
Horses are another issue. We need them, not too many other animals can do what they do for us, and they can't see very well at night. Perhaps our nocturnal humans are super cool and tame big cats for mounts instead. A fun thought, but big cats seem to me markedly less tractable than even a wild horse.
Lastly, somewhat tangentially, there are several critters that I believe would not change much, save for almost-passively encouraged selective breeding for night-time activity:
- Chickens don't really need to go anywhere beyond their immediate grounds. Easier to defend against foxes if the rancher is up at night, as well.
- Dogs are very, very useful. I can't imagine nocturnal cats could fill that role, they don't have a compatible instinctive social structure. It may even be useful to have some daytime dogs as well, to watch the chickens while the rancher sleeps and such.
My conclusions:
In the context of my though experiment, it seems as if nocturnal human civilization isn't going anywhere fast unless it innovates means to breed low-light vision into their livestock. If that can be achieved, I imagine similar animals are used.
I'm unsure if nocturnal humans would be driven to try and mold the typical livestock beasts into activity and utility at night time. We've done pretty crazy things to the physiology of our livestock beasts, so it doesn't seem out of the realm of possibility. But it also seems likely that the people would naturally orient their industries around their innate tendencies and capacities, and therefor, animal husbandry may be severely limited in nocturnal humanity to interaction with whatever nocturnal animals are endemic to a region.
Plainly I am not a zoologist or a big knower of animal types, so my ability to compare and contrast different potential livestock here is limited. I hope others can elucidate potential beasts that I have not considered.
Ideal answers will fact-check my research/theories above or contribute likely nocturnal human livestock animals that could fulfill the role of cows, pigs, sheep, and horses with explanations of why they are suitable.
