A thought occurred if spiders where huge and eat people when would they realize that if they left the victim alive they could produce blood again and be harvested again. I guess I’m asking when would they start to learn agriculture 

Newly born mammals are drinking mother milk. Human mother is giving milk only when she is pregnant. Humans noticed this relationship on themselves. Prehistoric humans noticed that there are other milk drinking animals such as e.g. sheep, goat, donkey. So once they caught them, killed at first, tried to get their milk and found it is also drinkable. But milk is gone if female is not pregnant (or dead). So had to release them (temporarily) or caught males to impregnate their previously caught females. Farm animals must be feed, or will die. so there was need to find source of food for them. Step by step, from gatherer and hunter culture to agriculture.

Production of blood is insignificant (inefficient) in comparison to production of milk by mammals.

"A dairy sheep will produce at most, 1100 lbs of sheep milk during a 180 day lactation. They can produce anywhere from 400 to 1100 pounds during their entire lactation."

1100 lbs is ~499 kg. 499 kg / 180 days = ~ 2.77 kg/day average.

 

Edited January 10, 20197 yr by Sensei

5 hours ago, AddaWord said:

Let’s say man eating spiders

... ...  oh no - please let's NOT!!!   lol.

5 hours ago, Sensei said:

Human mother is giving milk only when she is pregnant.

Guess again.

8 hours ago, Sensei said:

Human mother is giving milk only when she is pregnant.

Human mother is giving milk only when she was pregnant.. and gave birth to a newborn.

4 minutes ago, Sensei said:

Human mother is giving milk only when after she was pregnant.. and gave birth to a newborn.

 ftfy

Edited January 10, 20197 yr by dimreepr

10 hours ago, AddaWord said:

A thought occurred if spiders where huge and eat people when would they realize that if they left the victim alive they could produce blood again and be harvested again. I guess I’m asking when would they start to learn agriculture 

Not before they evolve a brain capable of learning agriculture.

Just now, zapatos said:

Not before they evolve a brain capable of learning agriculture.

Ants do not have a brain capable of learning many things, but they still have agriculture.

https://en.wikipedia.org/wiki/Ant–fungus_mutualism

"There are five main types of agriculture that fungus-growing ants practice:[5] lower, coral fungi, yeast, generalized higher, and leafcutter agricultural systems. Lower agriculture is the most primitive system and is currently practiced by 80 species in 10 genera.[6][7] Coral-fungus agriculture is practiced by 34 species by a single derived clade within the genus Apterostigma.[7]"

 

1 minute ago, Sensei said:

Ants do not have a brain capable of learning many things, but they still have agriculture.

https://en.wikipedia.org/wiki/Ant–fungus_mutualism

"There are five main types of agriculture that fungus-growing ants practice:[5] lower, coral fungi, yeast, generalized higher, and leafcutter agricultural systems. Lower agriculture is the most primitive system and is currently practiced by 80 species in 10 genera.[6][7] Coral-fungus agriculture is practiced by 34 species by a single derived clade within the genus Apterostigma.[7]"

 

Are you suggesting spiders can learn agriculture?

15 minutes ago, zapatos said:

Are you suggesting spiders can learn agriculture?

They do store food...

Just now, dimreepr said:

They do store food...

Are you suggesting that storing food is the same as agriculture?

27 minutes ago, zapatos said:

Are you suggesting spiders can learn agriculture?

Are you suggesting They cant?

36 minutes ago, zapatos said:

Are you suggesting spiders can learn agriculture?

https://en.wikipedia.org/wiki/Social_spider

 

There are social spiders that are both herbivores and carnivores certain species of both types display social behaviors, taking car of young, sharing food and various other social traits. None appear to be as advanced as insects, it should be said there are also social crustaceans and at least one land crustacean said to be dangerous to humans...   

20 minutes ago, dimreepr said:

Are you suggesting They cant?

Yes

They actually liquify most of their catch's internals.

Bone marrow is edible, not sure whether they do though or how often it is even an issue.