If anyone “believes most dinosaurs are colorblind,” it certainly isn’t most scientists. Most vertebrates, including birds and reptiles, see color better than humans, having four color receptors to humans’ three (and two in most mammals). Dinosaurs probably saw color just as well as birds, including the ability to see UV.
^^^ and as a consequence, dinosaurs likely had a range of colors and patterns, like reptiles or birds today.
Plain green or tan for some, but stripes and bars would be common, often in striking colors.
Humans impact this in a huge way. Even the game parks in Africa support far less animal biomass than they ideally could.
Before the arrival of humans, animals were actually limited by the plant matter available and the overall incoming solar energy the way you say.
Today’s ecosystems cannot come close to that theoretical maximum.
I don’t see how bringing a copy of the Player’s Handbook is going to help.
It’s handy to look up stats to see if your +2 Armor Piercing ammo will penetrate a ceratopsian’s frontal position armor modifier.
It won’t. 
Obviously it’s not going to look like a diorama in a museum, with dinosaurs of dozens of species packed shoulder to shoulder with an erupting volcano in the background.
But it’s not going to look like the woods near your house either. The woods near your house don’t have any predators larger than a coyote and don’t have any herbivores larger than a deer. All the larger animals are gone from this landscape.
It might look a bit like the Serengeti. Note that if you’re airdropped into the Serengeti it doesn’t always look like the famous wildlife photos, with hundreds of animals all around you. You might have to walk around for hours before you see some large animals. But there are times when you can look out on the grasslands and see thousands of grazers.
Except of course there was no grass during the Mesozoic, so there were no grazers. The plant community structure was completely different. The point that 100 units of plants support 10 units of herbivores who support 1 unit of carnivores is true. But it’s also incomplete. Go to a rainforest and look at the plant life, then try to find the animals. Very few animals compared to the plant productivity. Go to the African savanna and you’ll find animals everywhere, despite the fact that the rainforests have much greater primary (plant) productivity.
This is because herbivores can get a lot more useable food out of grass than they can out of rainforest trees. And given the well known gigantism of Mesozoic vertebrates, it’s pretty likely that Mesozoic herbivores could get a lot more nutrition out of Mesozoic plants than modern herbivores get out of modern plants.
Plant productivity is highly variable and depends on a bunch of limiting factors, and whichever limiting factor kicks in first is what creates the limit for the ecosystem. So in rainforests you have high sunlight and lots of water and stable high temperatures, so the limiting factors are CO2 and Nitrogen. In grasslands you get periodic dry seasons that kill trees. In deserts you get year-round dry seasons. In boreal forests you have lower sunlight and extremely low temperatures.
So during the Mesozoic there were global higher temperatures, no ice caps at the poles, and very high CO2. Which means global higher plant productivity. And we don’t know for sure but the types of plants eaten by the herbivores probably were more like grasslands than rainforests on the edibility scale. Even though there was no grass and angiosperms only in the later Cretaceous, the unpalatable gymnosperms of today aren’t good models for the gymnosperms that dominated the Mesozoic.
Thanks all for your responses.
The main gist seems to be as follows.
The wilderness today is much safer than it would have been back then primarily because humans and other natural forces have wiped out most of the predators that are large enough to eat a human.
Comparing the danger of the dinosaur time might be close to equivalent to the danger at the dawn of man both of which would be much more dangerous than today.
Even so encounters with man eating predators is not going to be an hourly experience, but would happen frequently enough to limit the prospects for long term survival of one unprepared (due to lack of equipment or lack of experience) for the potential dangers .
That about right?
Coyotes eat insects and lizards, as well as mice. Anything that moves is fair game. Grizzly bears eat moths, if that’s what they can find. The reason lions don’t eat rabbits is that there aren’t rabbits around, there are zebras and antelope and gazelles and wildebeast and such. If there were rabbits, they probably would eat rabbits.
But predator density does suggest fewer really large predators in an area, more smaller predators. Utahraptors would definitely look at humans as lunch.
Humans have spent over 10,000 years killing off large predators. When not killing them directly as threats to us, we kill them as threats to our livestock - animals we eat and raise for other reasons. When not killing them directly, we kill off their prey animals, both directly by competition (hey, I wanted that zebra-steak!) and indirectly by habitate destruction. We’ve been clearing forests, creating farms, and making cities forever. Human population has skyrocketed.
The paleo past isn’t going to look like the modern world.
If it’s a planned expedition with time travel logistics support, then humans will be able to do pretty well. There will be casualties, but we would adapt and overcome. If this is an accidental transplant of a handful of explorers, they’re not going to be equipped with heavy weapons, vehicles, etc. The Land of the Lost scenario is some folks on a raft fall off a waterfall and wind up in paleoland. That’s not a T-rex hunting expedition, that’s “Help help, the dinos are coming!”
With some time, planning, and effort, one could rig spears for defense, fire, and eventually some safe cubbyhole/fort/haven. But it would take constant vigilance, because while the predators may not come at you nonstop, when they do come you might not have much warning.
It’s like this: 23.5 hours a day you’re sitting on your ass and there’s no problem, but that 1/2 hour when the Utahraptors are at the door, it’s a very interesting time.
I don’t think it would be wall-to-wall predators, like the King Kong island scenario, where it’s one scary scrape to another, without any breathing room. But I would think it would be more dangerous than a hike through the Alaskan wilderness unarmed. It’s all about where and when.
Case in point, the show “I Shouldn’t Be Alive” had some harrowing tales. One involved a small group boating in Africa, and a hippo overturned the boat. One of the guys decided to go get help, and swam his way out of one of the heaviest crocodile infested rivers in Africa. It was sheer balls, determination, and luck that saw him through. He made it out to tell his story, but I wouldn’t count on that the next time you’re boating on an African river and you see some hippos.
I would say it is possible that the dinosaur times might be more dangeous than the old stone age, because dinosaurs had had more time to evolve and fill more niches and get more specialized. They weren’t just bigger than modern carnivores, they were faster, too, on the whole. And toothier. They had better color vision than mammals, and comparable abilities to smell things. Utahraptors had binocular vision, like humans. And of course, though not in T-rex range, some species were much larger than humans. So … fighting them off might have been a much tougher challenge. I don’t KNOW this, though … just speculating. Their small brains might also have made it possible to easily outthink them and kill them. It’s really hard to say. Some room for speculation there, I think, either way.
Dinosaur predators would probably be faster breeding than mammalian carnivores of a given size, because they actually occupied different econiches. Bears and tigers are at the top of the food chain (humans excepted), and usually only have two or so cubs a year to not outstrip their food supply. A 500 lb raptor would be only a second or third tier predator in its world, like coyotes or foxes compared to wolves or lions. So it would probably follow a strategy of breed prolifically, be an adaptable opportunist, and let the survivors carry on. Humans managed to nearly drive wolves and mountain lions extinct in North America, whereas coyotes were far more of a challenge. Imagine how dangerous coyotes would be if humans were only two feet tall. Humans in the Cretaceous might find that other than thinning out the raptor population in the immediate vicinity of their encampment, killing raptors would simply leave more food for the ones left.
It’s difficult to speculate because a lot depends on their temperament. I think our merry band of adventurers would be OK as long as they could win that first encounter. Show them that humans put up too much of a fuss to bother hunting. The pack hunters might learn to hang around the camp and eat our scraps. Maybe you could have your own pet Allosaurus or Albertosaurus. I wonder if after enough domestication they’d let you saddle up and ride. Might as well travel in style.
Or maybe they’re completely stubborn and vicious and they’d wait until a small group breaks away to go hunting/foraging and it’d be a smorgasbord.
Nope, quite the opposite on the oxygen front. Cite for the Cretaceous, I can find converse for the Jurassic if you like.
Sorry, I misremembered. I knew the oxygen levels were different but somehow I transposed high and low. Moral: Always check your memory. That’s why “Cite?” was invented.
I wish I could remember which schlocky SyFy movie it was that showed a native village fortified against dinosaurs. The perimeter was a field of fifty-foot logs stuck in the ground at an angle with sharpened ends facing outwards.
-
No. Predators are always uncommon relative to prey, or the ecosystem would become unbalanced. Predatory dinosaurs fossils, even of large specimens, are always far more rare than herbivores. Not that large herbivores are necessarily “safe”. Elephants, rhinos, and hippos can be quite dangerous to humans if confronted or threatened.
-
We don’t know if they were more aggressive, but there is no reason to think they would have been. Hollywood portrays them that way to sell tickets.
-
See above. All large animals are dangerous to humans. Camping the the Late Cretaceous would be a lot like camping in Africa, with similar amount of danger.
One thing to remember that Hollywood won’t show you: Dinosaurs are not immune to bullets.
-
True about proportionality, but there were more animals at all levels of the food chain before humans arrived. Dr Bakker spends some time on it in his Very Cool Book.
So there would have been more predators than we’re used to- and as mentioned upthread and in your post, modern humans aren’t used to ANY predators at all, even if Africa. -
No less so though.
-
Far, far more dangerous than any part of modern-day Africa.
Bullets are sketchy against hippos or other big mammals. Shooting at a 20-ton Triceratops while it charges you would be foolish with any sort of normal gun.
In addition, I think the point that Lumpy made about some raptors being large enough to easily attack and kill humans, and maybe faster than modern predators, and also being second or third tier predators who had a lot of offspring could make things even more dangerous.
Maybe 12-13 short tons. But yeah, from the front it presented almost a solid wall of bone. Problematic even for the largest man-portable gun.
Again, it depends on which time period we’re talking in which location with which species. Many if not most “raptors” were similar to things like secretary birds in size and may have preferred smaller prey (again, there are exception, but not universal ones across the entire Mesozoic). Juvenile tyrannosaurs would be a bigger threat than raptors, IMO. And their purported speed is a myth. The hind limb proportions of raptors are very short and stocky–good for short bursts of speed in an ambush style but not long pursuit like the long, lithe legs of small tyrannosaurs. Raptors were probably among the slowest predatory dinosaurs, certainly slower than most modern big cats.
(I’d take many things written by Dr. Bakker with a grain of salt–he’s notorious in paleo circles as erring on the side of sensationalism).
Another concern would be if these things would even see alien humans as prey. A bigger concern might be wandering into their territory, but areas could be made relatively safe.
“Shooting at a 20-ton Triceratops while it charges you would be foolish with any sort of normal gun.”
Same for an elephant, but people still routinely go to Africa without the kind of fear of certain death Hollywood relies on in its portrayal of dinosaurs as bloodthirsty Godzilla-like monsters rather than normal the animals they were.