Return of the Prehistoric Monsters! RAR!

[Majin Gojira]

Okay, this is a pretty complicated What If, but I'll try to pare it down.

Now, because of the quarantine stuff, a lot of videos are going around online about how animals are coming into normally urban/suburban places without humans to scare them off/less pollution/etc. A lot of it is Eco-Fascist BS, but parody's of it involving prehistoric animals got me thinking on a larger scale.

Starting in December of 2019, the number of so-called Living Fossils increases dramatically. For many smaller animals, herbivores and decomposed, it's in the hundreds of thousands of new individuals. For producers (plants), it's more in the millions of fully grown new individuals, forcing their way through any many-made structures as if they were made of tissue paper, should their habitat needs be met in places where people have set up shop.

Closer analysis of these reveals that these 'new' organisms are more resistant to man-made contaminants/pollutants, and better adapted for the environmental changes that humans are bringing about, more resistant to diseases and infections that threatened them before, and developed strategies for dealing with introduced predators that threatened them before. Including people themselves (IE: They will avoid humans if they can, and only attack if confronted/desperate).

And they generally appear within their former range, or near to it as they can to meet their overall habitat needs.

This ranges from large animals like Humpback Whales, Tapirs and Crocodiles, to smaller animals like Horseshoe crabs and Dragonflies. And for plants, it's things from Sequoias and Cyrpess, to the Eastern Walnut and Stromatolites.

The number that appears is based on size and role. The minimum is for 1 tonne or more apex predators, who only get 2000. Which, for some animals, is a godsend. Things down one trophic level multiply that by 10 (Tertiary Consumer, Secondary Consumer, Primary Consumer, Producer/Decomposer), and going down in size multiplies the number by 2 per stage (400-1000kg, 50-400kg, 1-50kg, 1kg or less, microscopic).

So, a Humpback Whale would have 20000 new members of its species that can now effectively filter/deal with plastics. As well as 20 million new krill to feed on.

But that is just the first wave.

The next round begins on January 1st and takes 2 forms. One, animals that went extinct within the last 100 years suddenly re-appear, with the same rates as the living fossils. So, about 12000 thylacines appear in Australia and Tasmania.
The next day sees animals from the next 1000 years, so Passenger Pidgeons and Carolina Parakeets re-appear in about 1.6 million strong numbers. This continues until January 10th. So, animals made extinct by humans after1000 CE have returned. So, New Zealand, Australia, New Caledonia, Madagascar, all get their megafauna back.

Elsewhere, animals from the Ediacaran and before appearing within suitable habitats, reasonably close to where they were found. So the deepwater fractal animal Charnia is in deep water areas with rather heavy marine snow, while the microbial mat grazers like Dickinsonia appear in microbial mat environments. These animals appear as relict species, having adapted to all the changes the environment has thrown but retain the same basic shapes as their ancient ancestors. IE: Increased intelligence/behavioral modifications to be roughly on par with modern animals in similar roles (IE: Dromaeosaurs and Troodontids will be Crow/Parrot smart, large Permian reptiles and the earliest or protomammals will be crocodile/cat smart, etc.), more efficient breathing for large insects, toxins to deal with many predators they wouldn't have faced normally, etc. They also have the advantages previously mentioned. Every day, 5 million years pass and roughly 3 to 10 new species appear to correspond to what was around at that time.

Plant, animals, and fungi.

So, on January 6th, the Cambrian begins, but little is noticed as most Cambrian animals are small, the biggest being Anomalocharis (up to 2m long).

The Ordovician begins on January 15th, and massive orthocones and trilobites start showing up.

The Silurian starts on January the 23rd, where a 3ft long semi-aquatic scorpion start showing up.

The Devonian begins around the end of January/start of February. Swamps seem to expand with the new plant growth, as well as Prototaxite giant fungi, and sea scorpions start going up rivers.

The Carboniferous sees more swamp expansion into places where there was o around places there are swamps, starting on February the 11th. Large amphibians and giant insects start appearing, and because amphibians can tolerate colder conditions than crocs, start being crocs in places as cold as Ohio and Lake Michigan.

February the 22nd begins the Permian period and the first large animals, where people realize that these larger animals are more heavily armored than expected. In short, a weave of fibers that are similar to kevlar, and the larger and more heavily armored the animal, the denser the weave. Up to a 3A rating for something like a Glyptodont or Ankylosaur. And like Kevlar, it's only really good against bullets, so the slashes, bites, and stings of the natural world basically ignore it.

March 4th begins the Triassic, though the "Age of Dinosaurs" doesn't kick off until the 14th, and comes to its end around April 10th.

And we don't reach the ice-age April 23rd.

Now, you ask, what animals show up since there are so many to choose from.

Well, the answer is ... well, do they appear in mass media? Movies? TV shows? Documentaries with animation rather than still frames of art with sound effects over them? A popular youtube series on prehistory? Maybe a young reader's based comic book on prehistoric life?

Well, that's what we got.

That's about 1420 species of animal (roughly), and 106 genera of plants.

If you have a specific species question, feel free to ask, I've... cataloged things.

A basic rundown of things by the end:
Coronavirus? Still happens. (Because I'd rather deal with this sort of animal revival than the "The Lamest Apocalypse Ever." Not trying to be exploitive, just me trying to cope with it via fantastical speculation.)

The northernmost regions, in general, have ice-age fauna returned to it.

Dinosaurs are limited to the tropics and sub-tropics by and large, but some fauna goes into temperate zones.

Permian and Carboniferous animals are found mixed from the tropics to continental climates.

There are a LOT of them.

And they are "Bullet Resistant"

The questions are:

How much chaos does this cause?

How do people react? Charismatic Megafauna is an effect that animals can have.

Which animals do you think will fare the best?

Which will be the most dangerous for people to handle?

What will survive the best?

And if you have any questions about what animals are out there, feel free to ask and I'll do my best to answer.

[Solauren]

Bullet resistant can run a very, very large range of 'resistance'
Can they take anti-tank rounds? What effect does a Desert Eagle, or a high powered rifle have on some of them?


Level of Chaos - In the tropics, a ton of it. You'll have Triceratops herds moving into Rio de Janerio, and poachers in Africa being chased by 'Raptors (serves them right). Northern climates - Really depends on a multiple of factors. There are bear species in the world that would make quick work of a Dire Wolf.

PETA might be in for a shock when some of the extinct species start attacking their anti-whaling boats. Japan will be shocked when the Whales attack the whaling boats. Imagine the reaction of some of the large oceanic dinosaurs to those boats. "Oh look - Sardines!"

Peoples Reaction: There would be a massive demand for young animals. i.e "Dire Wolf Puppies"
Hunter go nuts, and get eaten.

What species would have the hardest time?
The dinosaurs would have the worse time of it. For all intents an purposes, we're an alien world with the same gravity.
Different atmospheric composition, massively different diseases, and different climate. However, if they've adapted to our atmosphere, they'll rapidly be the apex species in their environments.

Most Dangerous Species?
The carnivores, any dinosaur, and some of the giant predator insects that used to exist. (You think scorpions or spiders are scary? They're the cute, cuddle versions of some of those things.)

Also, Australia at one time had a species of Kangaroo that was larger and faster then modern Kangaroo, and they had talons on their feet and were carnivores. Think 'furry Jurassic Park raptors, but that can jump further'. Australia's wilderness now makes Mad Max look like a vacation spot.

What will survive the best?
Returned mammal species. Like I said, to most species, this is an alien planet now.

[Majin Gojira]

Bullet resistant can run a very, very large range of 'resistance'
Can they take anti-tank rounds? What effect does a Desert Eagle, or a high powered rifle have on some of them?

it varies from animal to animal based on how armored they were beforehand. something 30-100kgs without armor would have a level 1 vest equivalent. Larger and more durable animals would have bullet-resistance up to level IIIa. You can learn what that means here.

Level of Chaos - In the tropics, a ton of it. You'll have Triceratops herds moving into Rio de Janerio, and poachers in Africa being chased by 'Raptors (serves them right). Northern climates - Really depends on a multiple of factors. There are bear species in the world that would make quick work of a Dire Wolf.

Dire Wolves lived with Grizzlys, Kodiaks, and worse--short-faced bears and did just fine, so I don't think that specific piece of competition will be as much a problem for them.

What will survive the best?
Returned mammal species. Like I said, to most species, this is an alien planet now.

Well, I did mention that they have compensation for modern developments. I mean, What's the fun of bringing back the 2m millipedes Arthropleura or the giant dragonfly Meganeuropsis if it's just going to suffocate immediately?

[Sky Captain]

What kind of potentially harmful bacteria and viruses comes with all the new animals? That would be the real deal. Small insects with high reproduction rates also could cause trouble if they can quickly take over existing ecological niches or attack food crops and are resistant to commonly available insecticides. Dinosaurs and other big predators are BIG, they can't hide easily, their reproduction cycle is slow. If they cause trouble they can be found and killed like any other large overly aggressive animal.

it varies from animal to animal based on how armored they were beforehand. something 30-100kgs without armor would have a level 1 vest equivalent. Larger and more durable animals would have bullet-resistance up to level IIIa. You can learn what that means here.

So not a big deal. You wouldn't go hunting large agressive animals with pistols anyway. A 12.7 mm rifle would pretty much ignore such puny armor. A headshot would be lethal to pretty much any animal that ever walked the Earth 7.62 mm also would penetrate, but may not do enough damage to drop large animal quickly.

[Majin Gojira]

What kind of potentially harmful bacteria and viruses comes with all the new animals?

Not many "NEW" things, but they can pick up and carry diseases and bacteria that their relatives have very quickly.

IE: Dinosaurs can carry H1N1.

Small insects with high reproduction rates also could cause trouble if they can quickly take over existing ecological niches or attack food crops and are resistant to commonly available insecticides.

The large insects don't have much of a reduced reproduction rate compared to their smaller counterparts.

So the giant like Pulmonoscorpous, Meganeura, and Arthropleura have similar concerns.

In general (because most subjects don't name specific species), there's Dragonflies, Bees, Weta, Barkbeetles, termites, ticks, "Dinosaur Fleas" (Psuedoplulex), True Cockroaches, Grasshoppers/Locusts, Caddisflies, Tarantulas, Vinegaroons, Katydids, Sawflies, camel spiders, Centipedes, Stick Insects, Harvestmen, Dameselflies, Lacewing, Scorpionfly, Butteflies, Wasps (Parasitic and nonparasitic), Mole Crickets, Mllipedes, Krill, Springtails Cicada, Leafhoppers, and Centipedes.

A lot of the sources portray them as big, and while I could have done a search for large species from prehistory of these animals... Even I'm not that nerdy.

Palaeodictoptera (proto-roaches that fly and chew plants, bigger than a human hand), Blattodea (giant true roaches that could fit in a sandwich) are two ancient extinct orders to deal with.

Protophasma is a primitive, and large, flying insect herbivore. A sort of basal bee.

Titanomyrma is a giant ant (queens are about 8cm long) related to modern Driver ants, and may have had a similar lifestyle, but they are acid sprayers rather than stingers.

Titanoptera is an order of proto-grasshoppers that acted as mantids.

Prodryas persephone is one species of butterfly from the paleogene that was actually named in a 'lost world' type scenario.

The Rocky Mountain Locust would be one of the 'early' returns, being extinct by the 1950s, and that was a plague-swarm variety. And now there's 16 Million of them.

The Green Ant gets a population boost (those make nests in trees by folding leaves and spray acid as a defense).

Another large flea, Saurophthirus, a 2.5cm brute of a big, is also around. They fed originally on pterosaurs.

Movies, and even documentaries, often put some speculation in their arthropods. Primarily, I've had to document a few cases of Arthropleura as Centipedes or similar 1m long centipedes.

And, of course, the infamous "Giant Spider" megarachne. Which spawned a "Mesothelae" and "Solifugae" large arachnid speculations.

Because I have a soft spot for Agathaumas I noted them as well, so... Why not just roll with 'em at this point.

So, we have a 3ft long venomous centipede, a "Mesothelae" spider about 54cm long in body length with a shell thickness comparable to a Coconut Crab, and a Solifugae camel spider about 45cm long.

But, really, those Rocky Mountain Locusts are probably going to be the worst problem to deal with.

So not a big deal. You wouldn't go hunting large agressive animals with pistols anyway. A 12.7 mm rifle would pretty much ignore such puny armor. A headshot would be lethal to pretty much any animal that ever walked the Earth 7.62 mm also would penetrate, but may not do enough damage to drop large animal quickly.

I mean, pretty much. It's a minor advantage. If they miss the killshot with a weapon on the cusp of the block-range, they will just send the animal running, or piss it off depending on the temperament. But a high caliber weapon (like an AK-47) or well aimed hit would be as effective as it would be on a similarly massed animal.

...

Which, given Alomosauurs is 75 tonnes, can be a challenge. Though the head being about 3ft long and on a pole would help a little...

A challenge, but doable.

[Sky Captain]

I think giant insects would be less of problem than for example some new species of mosquito that can spread malaria more easily or locust swarms that eats food crops. Big stuff is generally less numerous and much more easy to notice. If you have a big wasp flying around in your bedroom it is immediately noticeable not like few mosquitoes that can ruin whole nights sleep.

[Majin Gojira]

It's taken me half a damn year, but I finally ran some of the numbers for what creatures would be showing up.

About 2000 species.

This includes things like 2 Million Bison, Elephants, which wouldn't be small things to deal with.

But, let's start with the Arthropods. I'll bold ones I think may be the most dangerous overall.

"Living Fossils" getting a boost (of about 1 to 16 Million) include: Several species of spider (Giant Huntsman Spider, Goliath Bird Eater, Brazilian Wandering Spider, several Orb Weavers, Peacock Spiders, Australian Funnel Web Spider), Camel Spiders, Trapdoor Spiders, Vinegaroon, Centipedes (Scolopendra genus), Milipedes, Crabs (Blue Land Crab, Blue Crab, Fiddler Crab, Japanese Spider-Crab, Egg Crabs, Box Crab, Blue Crab), Krill, Mantis Shrimp, Triops, Scorpions, and Rempedes.

Insects get their own section. That includes Ants (Including, but not limited to Driver, Amazon, Weaver (Green), Leafcutter, Bull Ant/Jack Jumper Ant, Carpenter Ants, Turtle Ants, Honeypot Ants), Mosquito (several common species, including the giant Psorophora cilata -- which is an inch long), Termites (Mostly Mound Building species of South America and Africa), Cockroaches, Grasshopper/Locusts (Asian and North American genuses, Rocky Mountain Locust, Horsehead Grasshopper), Lacewing, Silverfish, Flies, Bees (European and Eastern Honeybee, Dawson's Burrowing Bee), Hornet, Praying Mantis, Stick Insects, Moths, Earwig, Cicada (Giant Cicada, Periodical Cicadas) , Crickets (Weta, Obake Raspy Cricket, Mole Cricket), Dragonflies, Dobsonfly, and Bristletails.

While the openly carnivorous and arthropods would only see an increase of 160,000 individuals, others (like the herbivorous ones) would see an increase in 16 Million.

However, true Locust Swarms, the devastating kinds, can number in the 80 million per square mile, so while a big group like this is dangerous, it's not initially devastating. It's when it breeds this pesiticde-resistant straing that things get worrying.

Plants, however, are probably going to be the most destructive since they will 'fill in' any open area they can, and disrupt paved areas.

120 Million Stromatolites showing up would cause some costal disruption along the more saline shores.

A lot of Algae that is shown in such things is of the multi-cellular variety, so that prevents a red tide from forming at least initially.

Liverworts and Mosses could cover buildings with each getting 160 Million individuals.

Then the ferns and trees hit. I counted about 160 living fossils and relict species of plants from the Horstail to the Giant Sequoia, each seeing 2 to 120 Million adult members of each species pushing their way into suitable habitat. With about half of those being 'trees', that does help curb climate change with the add on of average of 560 Million trees (when the current environmentalist cry of 18 Million (last I checked)).

Though not specified in the OP, it might be funny as hell if these new trees had a weave in their bark that gummed-up standard Chainsaw mechanics akin to the Kevlar-like weave in the animals.

But I digress.

The trees in particular will hit 'open spaces' pretty hard. Even assuming a base diameter of 1 yard, that would cover 300,000 square Miles of development projects, empty lots, logged areas, or even farmland partitions just in trees.

Without the ferns, horsetails, and grasses. Or Water lilies, lotus, and other water plants clogging up a few water ways.

Sure, there may be a million more elephants, but the plants is where the real disruption comes in.

[madd0ct0r]

Trees would mostly hit farmland. It's big open areas that are about 51% of total UK area, with another 16% being gardens and recreational areas.

Compare to 8% under tarmac or buildings, or 8% under forest already.

The world land area is 148 940 000 km squared according to wiki. 560 million trees, seems to be 3-4 trees per square km. Even if only a quarter of the land is suitable for trees to emerge on, that's a non issue. Noticeable in the desert perhaps, but people might not even notice in rural Wales.

[Solauren]

How well do these things hold up against modern pesticides, herbicides, and the like?

How well do the plants hold up to gardening tools and chainsaws?

How well do the animals hold up to high powered rifles?

[Majin Gojira]

Trees would mostly hit farmland. It's big open areas that are about 51% of total UK area, with another 16% being gardens and recreational areas.

Compare to 8% under tarmac or buildings, or 8% under forest already.

The world land area is 148 940 000 km squared according to wiki. 560 million trees, seems to be 3-4 trees per square km. Even if only a quarter of the land is suitable for trees to emerge on, that's a non issue. Noticeable in the desert perhaps, but people might not even notice in rural Wales.

The plants would show up in an area that would be normally suitable for them, or as close as they can get, so some plants would encroach on deserts, but not just appear smack dab in the middle of one. So, a few deserts might get 'slightly' smaller.

How well do these things hold up against modern pesticides, herbicides, and the like?

How well do the plants hold up to gardening tools and chainsaws?

How well do the animals hold up to high powered rifles?

Well in the OP:

Closer analysis of these reveals that these 'new' organisms are more resistant to man-made contaminants/pollutants, and better adapted for the environmental changes that humans are bringing about, more resistant to diseases and infections that threatened them before, and developed strategies for dealing with introduced predators that threatened them before. Including people themselves (IE: They will avoid humans if they can, and only attack if confronted/desperate).

That would make them resistant to pesticides, herbicides, and general pollutants.

Gardening tools and chainsaws would probably work. Also, a lot of these Living Fossils or Relict Species of plants include some food plants: Cacoa and Avocado among them.

Though it's very tempting to say they have a weave of kevlar in their trunks as well that does little to prevent them being eaten, but gums up chainsaw gears.

Higher power rifles will work on the animals, as the Kevlar rating for large animals is only 3A, but the heavily armored things like Glyptodonts, Ground Sloths, ankylosaurs, and the like would have higher ratings thanks to the dermal bone armor on top of the kvelar. (I think I mis-spoke about this in the OP).

The Glyptodonts have a solid shell of bone 2.5cm thick that is sheethed in keratin, the Ankylosaurs have thick bone chunks 2-5cm thick which are springy and covered another Keratin layer or unknown thickness (Keratin doesn't fossilized). And Ground Sloths? They have dermal denticles in their hide -- bone bits like chainmail, built in that actually made them effectively immine to light-to-mid weight arrow hits. Which isn't nothing...

Which may be enough, in combination, to push it to Level 3 Vests. Maybe 4.

And that's without taking size into account. But, yeah, guns WILL take these things down.

So, many of them avoid confrontation with humans, and recognize an armed human from an unarmed human and adjust their behaviors accordingly.

[Solauren]

So, realistically, the global ecosystem gets the global equal of a person with organ failure getting multiple organ transplants, the animals are smart enough to avoid humans (so the odds of hitting one with a car is low), and the plans can be cut back.

Really, besides an increase in bio and ecodiversity, and new research opprotunities, I don't see alot of impact.

[Majin Gojira]

So, realistically, the global ecosystem gets the global equal of a person with organ failure getting multiple organ transplants, the animals are smart enough to avoid humans (so the odds of hitting one with a car is low), and the plans can be cut back.

Really, besides an increase in bio and ecodiversity, and new research opprotunities, I don't see alot of impact.

It's a lot of the little impacts that would cascade from it and I think those are pretty interesting in and of themselves. The effects of Charismatic Megafauna on people gets them into trouble daily over in Yellowstone, so while the animals know to avoid humans when they are being 'dangeorus' (IE Armed), but the calculus of survival may mean they have to defend themselves (or take a very risky meal)), I'm sure people will still do stupid things around animals and get themselves hurt.

Not often, but enough to garner a few headlines at the very least.

Plus there's learning to live with the 'new neighbors' from the human side. They won't all be confined to parks (at least, at first).