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:

An elephant behind a number of hippos near the water.
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.

A large herd of wildebeests in a field.
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.

image of a brachiosaurus eating leaves from a tree
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.

What’s the Difference Between a Pirate and a Buccaneer?

geniebird/iStock via Getty Images
geniebird/iStock via Getty Images

Talk Like a Pirate Day is returning to port on September 19th and you can bet your boots that a few celebrants will be using the terms pirate and buccaneer interchangeably. Most people do. Nevertheless, these two words aren’t actually synonymous.  

Four hundred years ago, if you were a seafaring thief, the label that you received said a great deal—mainly about whoever it was doing the labeling. Anyone who called you a "pirate" probably hated your guts. But those who cited you as a “buccaneer” might have had a very different attitude. Within certain contexts, the latter group may have even embraced you as a national hero.

Time for a swashbuckling semantics lesson. In article 101 of the United Nations Convention on the Law of the Sea (UNCLOS), piracy is defined as "any illegal acts of violence or detention ... committed for private ends by the crew or the passengers of a private ship." UNCLOS also states that, to be considered piracy, a crime must occur within international waters. If the event in question takes place within a particular country’s territorial waters, the aggressors will be deemed armed robbers rather than pirates.

Historical definitions tended to be a lot broader. During the 17th and 18th centuries, England regarded piracy as any criminal act committed on the high seas or below the low tide mark around shores, rivers, and estuaries. Hundreds of years earlier, in the year 100 CE, Plutarch—a noteworthy Greek scholar— talked about pirates as anybody who attacked a ship or maritime city without legal authority.

Just what did he mean by “legal authority?” Plutarch was probably alluding to warships. Nowadays, these are generally owned by national governments, but this wasn’t always the case. From medieval times through the early 20th century, it was common practice for a nation at war to recruit private vessels to assault its enemy’s ships, steal their goods, and plunder their ports. Mariners who engaged in such state-approved mischief were called “privateers.”

Usually, a privateer vessel was allowed to operate under a license that was granted by the country it served. Dubbed the Letter of Marque, this document laid out a code of conduct and payment policy for the crew. (Privateers almost always got to keep a percentage of whatever they took.)

Essentially, privateers were independent contractors, acting as hostile, government-commissioned, seafaring mercenaries. Therefore, they technically weren’t pirates because real pirates didn’t behave in accordance with any national laws or regulations. But the dividing line here was pretty blurry. Many privateers eventually became pirates and vice versa. Also, a captured privateer would sometimes be tried as a pirate by the country he or she was victimizing.

This brings us back to buccaneers: Throughout the 16th through 18th centuries, Spain more or less controlled the Caribbean. However, in the 1600s, she started to get some not-so-friendly competition. By the middle of that century, settlers from various other European countries—including England, France, and the Netherlands—had colonized parts of the Leeward Islands and Hispaniola. Among these newcomers, transplanted Frenchmen were especially common. The Gallic colonists would frequently smoke their meat over a wooden platform that they called a boucan. Thanks to this cooking technique, the frontiersmen were given the nickname “buccaneers.”

Before long, many turned to piracy. Because of Spain’s huge colonial presence in the Caribbean, buccaneers more or less exclusively targeted Spanish ports and ships. This turned plenty of heads across the Atlantic. In an attempt to cripple Spain’s empire, the English, French, and Dutch began issuing Letters of Marque to buccaneer vessels.

Eventually, the word buccaneer came to possess its current—and very specific—definition, which is: “any of the piratical adventurers who raided Spanish colonies and ships along the American coast in the second half of the 17th century.” (Told you it was specific.)

The most famous buccaneer of them all was undoubtedly Sir Henry Morgan. Little is known about his early life, although most historians believe that he was born in Wales at some point in 1635. Nearly 20 years later, he set sail for Barbados as a member of an expedition that saw England seize Jamaica from the Spanish.

Morgan quickly emerged as a leading buccaneer, and as England’s most ruthlessly effective privateer. In 1668, he seized the heavily guarded city of Porto Bello, Panama, holding it for ransom until the Spanish coughed up an amazing 250,000 pesos. Three years later, Morgan raided and sacked Panama City, which promptly burned to the ground. Such exploits did not endear him to the Spanish, but in England, Morgan was a widely beloved figure. Knighted by King Charles II, he was made Lieutenant Governor of Jamaica in 1674. Following his death on August 25, 1688, Morgan received a grandiose state funeral, complete with a 22-gun salute.

And, yes, that rum was named after him. Clearly, buccaneering had its perks. 

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Why is Friday the 13th Considered Unlucky?

iStock
iStock

Today, people around the globe will feel uneasy about getting out of bed, leaving their homes, or going about their normal daily routines, all because of a superstition. These unfortunate folks suffer from paraskavedekatriaphobia, a common neurosis familiar to us all: the fear of Friday the 13th. But just where did this superstitious association come from, and how did it catch on?

The truth is that no one is absolutely sure where the idea that Friday the 13th is unlucky originated. Donald Dossey, the founder of the Stress Management Center and Phobia Institute in Asheville, North Carolina, suspects the fear can be traced back to a Norse myth about 12 gods who had a dinner at Valhalla—the fabled hall where legendary Norse heroes feasted for eternity after they died—that was interrupted by a 13th guest, the evil and mischievous god Loki.

According to legend, Loki tricked Höðr (the blind god of winter and son of Odin, the supreme god in Norse mythology) into shooting his brother Baldr (the benevolent god of summer who was also a son of Odin) with a magical spear tipped with mistletoe—the only substance that could defeat him. Thus the number 13 was branded as unlucky because of the ominous period of mourning following the loss of such powerful gods by this unwanted 13th guest.

For whatever reason, among many cultures, the number 12 emerged throughout history as a "complete" number: There are 12 months in a year, 12 signs of the zodiac, 12 Gods of Olympus, 12 sons of Odin, 12 labors of Hercules, 12 Jyotirlingas or Hindu shrines where Shiva is worshipped, 12 successors of Muhammad in Shia Islam, and 12 tribes of Israel. In Christianity, Jesus was betrayed by one of his 12 Apostles—Judas—who was the 13th guest to arrive for the Last Supper. Surpassing the number 12 ostensibly unbalances the ideal nature of things; because it is seen as irregular and disrespectful of a sense of perfection, the number 13 bears the stigma of misfortune and bad luck we know today.

WHY FRIDAY?

Friday joins in the mix mostly because all of the early accounts of Jesus’s crucifixion agree that it took place on Friday—the standard day for crucifixions in Rome. As Chaucer noted in The Canterbury Tales, "And on a Friday fell all this mischance." Yet perpetuating Friday as an unlucky day in America came from the late 19th-century American tradition of holding all executions on Fridays; Friday the 13th became the unluckiest of days simply because it combined two distinct superstitions into one. According to the Oxford University Press Dictionary of Superstitions, the first reference to Friday the 13th itself wasn’t until 1913. (So despite actually occurring on Friday, October 13, 1307, the popular notion that the Friday the 13th stigma comes from the date on which the famed order of the Knights Templar were wiped out by King Philip of France is just a coincidence.)

The repercussions of these phobias reverberated through American culture, particularly in the 20th century. Most skyscrapers and hotels lack a 13th floor, which specifically comes from the tendency in the early 1900s for buildings in New York City to omit the unlucky number (though the Empire State Building has a 13th floor). Some street addresses also skip from 12 to 14, while airports may skip the 13th gate. Allegedly, the popular Friday the 13th films were so-named just to cash in on this menacing date recognition, not because the filmmakers actually believed the date to be unlucky.

So, is Friday the 13th actually unlucky? Despite centuries of superstitious behavior, it largely seems like psychological mumbo jumbo. One 1993 study seemed to reveal that, statistically speaking, Friday the 13th is unlucky, but the study's authors told LiveScience that though the data was accurate, "the paper was just a bit of fun and not to be taken seriously." Other studies have shown no correlation between things like increased accidents or injuries and Friday the 13th.

And Friday the 13th isn't a big deal in other cultures, which have their own unlucky days: Greeks and Spanish-speaking countries consider Tuesday the 13th to be the unluckiest day, while Italians steer clear of Friday the 17th. So today, try to rest a little easy—Friday the 13th may not be so unlucky after all.

Additional Source: 13: The Story of the World’s Most Popular Superstition.

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