u/growingawareness

Megaherbivores are said to be incapable of withstanding human predation due to how slowly they reproduce, which explains why the vast majority of them went extinct long ago. However, I'm curious as to why African and Asian elephants and rhinos were able to survive the last 5000+ years of extensive exploitation, combined with habitat loss.

Ivory trade has been massive throughout history, but there was obviously also local hunting for meat surely. And the human population of South and Southeast Asia in particular has been enormous, hundreds of millions of people which would invariably lead to habitat loss. Yet, until only the last few centuries, these animals were not endangered. How is that possible?

Main topics, as of now:

-Archaeogenetics and peopling of Sahul (Australia, New Guinea, Tasmania), including busting common misconceptions

-Landscape alteration through use of fire (fire-stick farming)

Any other topics you think I should address too?

High functioning, high masking individuals with autism spectrum disorder will often show the same traits such as a fear of rejection and social interactions, so what criteria do clinicians use to differentiate the two?

High functioning, high masking individuals with autism spectrum disorder will often show the same traits such as a fear of rejection and social interactions, so what criteria do clinicians use to differentiate the two?

I’ve heard of cave wolves (from Europe) along with Beringian and Pleistocene wolves.

Are both cave wolves and Beringian wolves just populations within the Pleistocene wolf clade? Additionally, when exactly did Pleistocene wolves emerge?

Why do some animals just opt to have small populations? The bluebuck, which was hunted to extinction a few hundred years ago, was found to be an animal which had a long history of small population size and low genetic diversity for hundreds of thousands of years, which made it later vulnerable to extinction via overhunting. That's in contrast to its nearest relative, the sable antelope and roan antelope, which are plentiful in Africa.

So my question is why would this be the case? What's the benefit to being small numerically for a species?

When it comes to the Late Pleistocene extinctions, the go-to explanation for why Africa retained most of its megafaunal biodiversity and other continents did not is because humans evolved in Africa and hence the megafauna there developed defenses against human hunting behavior. I still think this is definitely true, but I do wonder how much other causes were also responsible. Two I can think of:

Humans becoming superb hunters as a result of evolving in Africa. Think about it. Africa was a guild that had already been dominated by ungulates since before hominins emerged. Ungulates are fast-running, usually agile creatures. That’s different from say, South America where megafauna were majority Xenarthran or Australia where they were marsupials. There was no “easy” hunting in Africa-it was life on hard mode. Hence, when they moved to certain other continents, they found fauna that they could easily dominate.

This isn’t an aspect that gets much attention, but it’s something I’ve thought about a lot.

Technological progress following migration: after humans left Africa, they had to adapt to their new environments and that pushed them to develop new technologies. Humans used advanced hunting tools like micro blades, fluted tips, atlatls, and domesticated dogs as they conquered northern Eurasia and the Americas, so animals living there were facing especially lethal humans.

What do you guys think? Which of these factors do you think were most decisive?

I’ve heard somewhere that introduced bison in Alaska needed supplemental feeding to survive winter. Is this true, and if not, are there examples where they live year round in such habitats?

I've read that plants that grow in moist areas are less nutritious than those that grow in dry areas due to having lower protein, calcium, albumin and other essential minerals in them. However, if that's the case, why is it that swamp/marshland regions like the Okavango Delta and Kaziranga support so many large animals?

I've read that plants that grow in moist areas are less nutritious than those that grow in dry areas due to having lower protein, calcium, albumin and other essential minerals in them. However, if that's the case, why is it that swamp/marshland regions like the Okavango Delta and Kaziranga support so many large animals?

These are located south of the Black and Caspian Seas respectively which would initially make the high precipitation make sense, but don't westerly winds blow in the opposite direction (towards the sea)?

As I understand, it's known that trees do not grow in areas that have average temperatures of the warmest month below 10 C (50 F). It makes sense for the most part as trees need sufficient warmth to grow.

However, I don't understand why this is such a hard limit. For example, hypothetically, let's say that you have a place with a July average of 8-9 Celsius, but also a mild spring, fall, and winter as you see in areas with subpolar oceanic climates. These areas still end up being treeless, whereas areas with very short but relatively warm summers (above 10 C) and very cold spring/fall/winter wind up with trees.

Could anyone explain this to me?

https://preview.redd.it/fy5losjyw8yg1.jpg?width=267&format=pjpg&auto=webp&s=2bae7056cee006bcda75ae5e79f911c71eb42dc5

This map is global aridity index, different from precipitation alone as it accounts for evaporation rates but raw precipitation maps reveal the same pattern. As you can see, the area in the red circle is a lot drier than areas directly adjacent to it, like Korea, further south China, as well as the Russian Far East and Japan.

Why is this? It's not inland, it's right next to the Yellow Sea. Shouldn't the East Asian Summer Monsoon be just as strong as in neighboring areas?

It can't be orographic effects alone because Incheon (South Korea) and Shanghai (central China) are the same elevation as Jinan, Beijing, Shenyang, Dalian in the arid zone but have much higher precipitation.

Most monsoons seem to occur mainly at tropical and subtropical latitudes, but the East Asian summer monsoon extends deep into the mid latitudes in northern China, Korea, northern Japan, and the Russian Far East.

How is this possible exactly?