Why Were Dinosaurs So Large and Why Don't Animals of That Scale Exist Today?

iStock.com/Kirkikis
iStock.com/Kirkikis

Untorne Nislav:

Before we start, what you need to realize is that dinosaurs were definitely large, but not so large. You probably know the numbers: the largest land mammals ever are around 6–8 meters long (19-26 feet), while the largest dinosaurs were … is it 40 meters (131 feet)?

Damn, what a number!

However, numbers can be veeeery misleading. Look at the second-largest land mammal ever, Indricotherium, and one of the largest dinosaurs, Brachiosaurus, here.

The difference seems to be incomparable …

However …

Those are two entirely different body shapes: most of the brachiosaur's length is used up by its enormous neck and tail. To make it fair, I want you to use your two thumbs: place one over the dinosaur’s neck, and the other over the tail (hopefully, you are not reading this from a touchscreen).

And suddenly, enormous becomes quite … normous. Obviously, Brachiosaurus is still larger than Indricotherium, but it's not four times larger like the numbers would suggest. The real, fair difference between the two is roughly the same as the difference between an elephant and a hippo:

iStock.com/JurgaR

Moral of the story: don't let the body shape mislead you.

So here's the answer to the "so large" part of your question: because they weren't.

However, there is still some "true" difference in size to account for. And at least two factors could've contributed to it:

1) Different rules of herbivory.

In the age of mammals, the most effective strategy of herbivory is grazing.

iStock.com/WLDavies

Grasslands are super-effective. The two most productive mammal-dominated ecosystems ever are savannas and (now gone) mammoth steppes: both can feed enormous numbers of huge mammals. With grasses growing at insane rates everywhere, no other food source on Earth can provide for such high mammalian biomasses.

Moral of the story: if you want to grow up big and full, eat grasses.

However, it wasn't always so. In times of dinosaurs, grasses didn't exist. So, the largest animals then were forced to resort to the second-best herbivory strategy: browsing.

iStock.com/MR1805

Tree foliage doesn't grow like grasses, yet still there's usually a considerable amount of it per area unit, because it overlaps vertically many times.

Dinosaurs that fed from canopies could afford to grow large: for thermoregulation or defense from predators—usual reasons.

However …

Any animal that grows too big inevitably experiences difficulties with food. At present, any herbivore that became too large would likely just move onto grasses. But dinosaurs couldn't. Hence, the only solution that they had was to grow necks even longer to get even more foliage. But if you grow a larger neck, you also need a larger tail (for balance). Then, you also need broader and thicker bones for all those muscles to attach, stronger legs to support the extra tons of weight, and so on and so on.

Effectively, it was a dead loop: dinosaurs became large, then they grew longer necks to support the growing need for food, which in turn made them become even larger, which in turn further increased their need for food. Browsing herbivory was likely the driving force of sauropod size, and in the end, the only limiting factor was probably the height of the highest canopy.

2) Reproductive limitations

This one doesn't really answer the "why sauropods were large?," but the "why mammals aren't that large?".

A typical sauropod was, effectively, a reproductive frog. It laid dozens if not hundreds of small eggs that hatched into very small babies that had little to do with adults: they occupied very different niches and fed on different food. For sauropods, it killed two problems: firstly, it made pregnancies easy and unnoticeable (which is a factor when you weighed 60 metric tons), and secondly, it removed competition for food between adults and babies.

In other words, sauropods could afford to become as large as necessary without worrying much about how it would affect their pregnancy and reproduction.

On the contrary, being a pregnant 60-tonne (66-ton) mammal is a nightmare—of a real and deadly kind.

All (placental) mammals bear relatively large offspring. However, if you weighed 60 tonnes, that would be … what, 2 tonnes (4400 pounds) heavy offspring? Carrying extra 10 kilograms (22 pounds) of weight at the peak of pregnancy is difficult enough for humans, but having to carry 10 extra tonnes (22,000 pounds) is just impossible, unless you are a whale and swim.

Not to mention that it would be a very long pregnancy.

Not to mention that pregnant females require even more food.

Not to mention that the young must be fed, only to grow up to compete with you for the same food later.

Moral of the story: children are expensive … unless you are a frog or a sauropod.

Q: How about livebearing smaller babies?

There are two problems with this. Firstly, it just doesn't happen. There are relatively small newborns in some placental mammals, but nothing like the difference between sauropod adults and babies.

Secondly, if babies are too small, then they become unavailable for social interactions: in fact, they are better to stay away from parents immediately to avoid being stomped on. Social behavior and learning are the backbone of mammalian success. Trying to get rid of it just isn't worth it.

So in the end, dinosaurs that weren't so large were large because they bred like frogs and because their kitchen was … a little underrepresented.

This post originally appeared on Quora. Click here to view.

10 Rad Gifts for Hikers

Greg Rosenke/Unsplash
Greg Rosenke/Unsplash

The popularity of bird-watching, camping, and hiking has skyrocketed this year. Whether your gift recipients are weekend warriors or seasoned dirtbags, they'll appreciate these tools and gear for getting most out of their hiking experience.

1. Stanley Nesting Two-Cup Cookset; $14

Amazon

Stanley’s compact and lightweight cookset includes a 20-ounce stainless steel pot with a locking handle, a vented lid, and two insulated 10-ounce tumblers. It’s the perfect size for brewing hot coffee, rehydrating soup, or boiling water while out on the trail with a buddy. And as some hardcore backpackers note in their Amazon reviews, your favorite hiker can take the tumblers out and stuff the pot with a camp stove, matches, and other necessities to make good use of space in their pack.

Buy it: Amazon

2. Osprey Sirrus and Stratos 24-Liter Hiking Packs; $140

Amazon

Osprey’s packs are designed with trail-tested details to maximize comfort and ease of use. The Sirrus pack (pictured) is sized for women, while the Stratos fits men’s proportions. Both include an internal sleeve for a hydration reservoir, exterior mesh and hipbelt pockets, an attachment for carrying trekking poles, and a built-in rain cover.

Buy them: Amazon, Amazon

3. Yeti Rambler 18-Ounce Bottle; $48

Amazon

Nothing beats ice-cold water after a summer hike or a sip of hot tea during a winter walk. The Yeti Rambler can serve up both: Beverages can stay hot or cold for hours thanks to its insulated construction, and its steel body (in a variety of colors) is basically indestructible. It will add weight to your hiker's pack, though—for a lighter-weight, non-insulated option, the tried-and-true Camelbak Chute water bottle is incredibly sturdy and leakproof.

Buy it: Amazon

4. Mappinners Greatest 100 Hikes of the National Parks Scratch-Off Poster; $30

Amazon

The perfect gift for park baggers in your life (or yourself), this 16-inch-by-20-inch poster features epic hikes like Angel’s Landing in Zion National Park and Half Dome in Yosemite National Park. Once the hike is complete, you can scratch off the gold foil to reveal an illustration of the park.

Buy it: Amazon

5. National Geographic Adventure Edition Road Atlas; $19

Amazon

Hikers can use this brand-new, updated road atlas to plan their next adventure. In addition to comprehensive maps of all 50 states, Puerto Rico, Canada, and Mexico, they'll get National Geographic’s top 100 outdoor destinations, useful details about the most popular national parks, and points on the maps noting off-the-beaten-path places to explore.  

Buy it: Amazon

6. Adventure Medical Kits Hiker First-Aid Kit; $25

Amazon

This handy 67-piece kit is stuffed with all the things you hope your hiker will never need in the wilderness. Not only does it contain supplies for pain, cuts and scrapes, burns, and blisters (every hiker’s nemesis!), the items are organized clearly in the bag to make it easy to find tweezers or an alcohol wipe in an emergency.

Buy it: Amazon

7. Hiker Hunger Ultralight Trekking Poles; $70

Amazon

Trekking poles will help increase your hiker's balance and stability and reduce strain on their lower body by distributing it to their arms and shoulders. This pair is made of carbon fiber, a super-strong and lightweight material. From the sweat-absorbing cork handles to the selection of pole tips for different terrain, these poles answer every need on the trail. 

Buy it: Amazon

8. Leatherman Signal Camping Multitool; $120

Amazon

What can’t this multitool do? This gadget contains 19 hiking-friendly tools in a 4.5-inch package, including pliers, screwdrivers, bottle opener, saw, knife, hammer, wire cutter, and even an emergency whistle.

Buy it: Amazon

9. RAVPower Power Bank; $24

Amazon

Don’t let your hiker get caught off the grid with a dead phone. They can charge RAVPower’s compact power bank before they head out on the trail, and then use it to quickly juice up a phone or tablet when the batteries get low. Its 3-inch-by-5-inch profile won’t take up much room in a pack or purse.

Buy it: Amazon

10. Pack of Four Indestructible Field Books; $14

Amazon

Neither rain, nor snow, nor hail will be a match for these waterproof, tearproof 3.5-inch-by-5.5-inch notebooks. Your hiker can stick one in their pocket along with a regular pen or pencil to record details of their hike or brainstorm their next viral Tweet.

Buy it: Amazon

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Can the Electoral College Reverse the Results of an Election?

Tumisu, Pixabay // Public Domain
Tumisu, Pixabay // Public Domain

Every four years, people talk about the oddness of the Electoral College. And just like 2000's popular vote/Electoral College mismatch, after the 2016 election, some citizens attempted to flip electors from Donald Trump to either Hillary Clinton or a third candidate (if enough electors go to the third candidate, the House would then have to choose from among the top three).

Which leads to the question: Can the Electoral College actually change the results of the election? It’s an awkwardly worded question for a very specific reason, and the answer is no. But for the question people think that they’re asking—could the Electoral College reverse the results of the election?—the answer is yes, although it’s profoundly unlikely.

The reason it’s an oddly worded question is that the November election is not a vote for president. The vote is for a set of electors who will then go and vote for the president in December. Therefore, the electors cannot change the results of the election since they’re the ones being elected. In one of the Federalist Papers, Alexander Hamilton explained the reasoning for forgoing direct democracy, as well as why they avoided letting politicians make the decision. Largely, the problem was that neither the public nor the politicians could be trusted. Hamilton wrote:

“The Executive should be independent for his continuance in office on all but the people themselves. He might otherwise be tempted to sacrifice his duty to his complaisance for those whose favor was necessary to the duration of his official consequence. This advantage will also be secured, by making his re-election to depend on a special body of representatives, deputed by the society for the single purpose of making the important choice.”

There were other issues the Founding Fathers were trying to avoid as well, such as the risk of a smorgasbord of regional candidates. As historian Jack Rakove told Stanford News in 2012, “it would become truly difficult to produce a popular majority with a field of favorite sons.”

More controversially, the Founding Fathers faced the issue of slavery. Because enslaved people couldn’t vote, a direct popular vote would weaken the power of the South. Thanks to the three-fifths compromise, however, the slave states had greater power under an electoral system than under a direct voting system, because enslaved people couldn’t vote but did count for the number of representatives. And more representatives meant more electors (the number of electors equals the state’s number of representatives plus the number of senators). As James Madison said in 1787:

“There was one difficulty however of a serious nature attending an immediate choice by the people. The right of suffrage was much more diffusive in the Northern than the Southern States; and the latter could have no influence in the election on the score of the Negroes. The substitution of electors obviated this difficulty and seemed on the whole to be liable to fewest objections.”

But objections to the elector’s powers appeared as soon as races got competitive. In 1796, Pennsylvanian Samuel Miles became the first known faithless elector when, despite being chosen as a Federalist, he voted for opposition candidate Thomas Jefferson. In a letter to the Gazette of the United States, a disgruntled Pennsylvania voter asked, “What, do I choose Samuel Miles to determine for me whether John Adams or Thomas Jefferson shall be President? No! I choose him to act, not to think.”

SO WOULD IT WORK?

As we have written about before, in about half the states plus Washington, D.C., electors are required to vote for their state’s popular vote winner—some states to the point that any attempt to defy this would forfeit the elector’s position. They’re extreme, but in the controversial 1952 Ray v. Blair case, the Supreme Court ruled that requiring pledges from electors to vote for a particular candidate was constitutional. But the question that remains unanswered is whether any punishment for breaking those pledges is constitutional. It’s never mattered, but would quickly become a critical issue if electors defected en masse.

Regarding the 2016 election, others say that because Hillary Clinton had already conceded, this strategy wouldn’t have worked. But there’s no requirement that an elector vote for a viable candidate. In 1976, one of the electors voted for Ronald Reagan, who hadn’t even won his party’s primary. In 1956, another elector voted for a local circuit court judge rather than Adlai Stevenson.

A stronger issue standing in the way is how electors are chosen. Generally, in spring and summer, each state’s political parties nominate a slate of electors from a list of party faithful. Any attempt to get defections would require electors to go against a party that chose them specifically for their loyalty.

The Ray v. Blair decision gave one of the most famous dissents in Supreme Court history, where Justice Jackson wrote, “No one faithful to our history can deny that the plan originally contemplated, what is implicit in its text, that electors would be free agents, to exercise an independent and nonpartisan judgment as to the men best qualified for the Nation's highest offices.” While it would be considered highly irregular and is highly unlikely, the possibility is there. And will remain there until January 6, 2021, when the votes are officially counted before a joint session of Congress.

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