Unlocking the Mysteries of Titanosaurs' Colossal Proportions: Uncovering the Reasoning Behind the Dinosaurs' Enormous Size

Dinosaurs hold the record as the largest terrestrial animals to have ever existed. Titanosaurs, including Puertasaurus, Patagotitan, and Argentinosaurus, were the biggest of them all, surpassing a blue whale in length and perhaps weighing as much as ten or more elephants.

To uncover how these behemoths grew so massive, take a look at our animation below.

The Titanosaurs: Giants Among Giants

While dinosaurs like Spinosaurus and T. rex are often associated with size, they pale in comparison to the truly colossal creatures that roamed the Earth.

You might think of Diplodocus or Brachiosaurus as the real heavyweight champions, but they’re small fry compared to the titanosaurs, the last surviving group of sauropods. Take Patagotitan, for example, nearly 50% longer than Diplodocus, twice as tall, and four times heavier.

Patagotitan stretched an enormous 37.5 metres in length, weighing a staggering estimated 57 tonnes. In comparison, Diplodocus is a featherweight, only reaching a mere 26 metres in length and tipping the scales at a paltry 15 tonnes.

Professor Paul Barrett, our esteemed dinosaur expert, comments, “Although the blue whale may be renowned as the biggest animal ever to have lived, it’s a bit of a fraud. Living in the ocean helps the blue whale support its weight.” Whales lack the muscle and bone structures to carry their own weight, which means they’ll perish if they’re stranded. Conversely, dinosaurs always supported their massive heft.

Without a doubt, titanosaurs like Puertasaurus, Patagotitan, and Argentinosaurus are the mightiest creatures ever to have walked the Earth.

Uncover further information about the largest dinosaurs on record and the scientific methods that discover their size by following this link: 11 of the biggest dinosaurs and how scientists work out their size.

Do Dinosaurs Compare to the Biggest Land Mammals?

The African savanna elephants, Loxodonta africana, take the title for today's most substantial land animal species. Typically, they weigh five to seven tonnes. In contrast, the most massive titanosaurs weighed approximately ten times more, or maybe even more.

Although the extinct rhinoceros relative, Paraceratherium, holds the record for the most significant known land mammal to have ever lived - at least that can be measured reliably. This mammal grew to approximately 7.4 meters in length, just under five meters in height, and measured up to 20 tonnes. The prehistoric elephant Palaeoloxodon namadicus may have been slightly larger, but not enough fossil material has been found to provide a precise estimate of its body mass.

Paul explains that sauropods were the only group that outdid the most massive land mammals. What's fascinating is that theropod dinosaurs such as Spinosaurus and T. rex were also the only animals to surpass the most sizeable land-based mammalian predators in size.

While not all dinosaurs were gargantuan, they were the largest land creatures to ever exist. Some dinosaurs were quite small, for example, Compsognathus was merely about 2.5 times the size of an average man's footprint. Bird-like dinosaurs and birds are even smaller. © Dotted Yeti/ Shutterstock

So Why Could Some Dinosaurs Grow So Gigantic?

Numerous theories have been put forward to explain how dinosaurs attained sizable dimensions, such as lower gravity and higher oxygen levels in the atmosphere, but most of them have been disproven.

For example, for Earth's gravity to decrease significantly, the planet would abruptly need to shrink in size, which didn't happen. Instead, Earth grew much more massive early in its history, long before life existed, and has remained relatively constant in size since then.

Similarly, oxygen levels in the Mesozoic Era were not much different from what they are now, so that alone couldn't account for the colossal dimensions of certain dinosaurs.

Scientists now believe that a variety of characteristics enabled dinosaurs to grow to such massive sizes. Continue reading or watch our video to learn more.

The Shape of the Dinosaur's Body

Upright Posture

All dinosaurs had a vertical, pillar-like stance. This posture provided greater support for a larger body than the sprawling stance of other reptiles such as crocodiles and lizards. Furthermore, it allowed dinosaurs to move with less energy expenditure.

All dinosaurs shared the body form advantage, but two legs facilitated running, so all predatory dinosaurs were bipedal. In contrast, four legs were capable of carrying a much larger body mass.

This is why the most massive bipedal dinosaurs, such as Spinosaurus, Tyrannosaurus, and Giganotosaurus, only weighed roughly seven tonnes, which is still gigantic. In comparison, the most extensive sauropods were about eight to ten times larger, balancing their weight on four legs.

Distinct Hands and Feet

To carry their massive weight, sauropods had specific features that made them more stable. Their wrists and ankles had reduced mobility, which amplified their strength. Additionally, their hands and feet resembled those of elephants in both size and padding, which helped distribute their weight evenly.

Ample Hips

Titanosaurs, which came after earlier sauropods, had wider hips that provided greater stability. These hips also created more space for their large stomachs, which meant they could consume more plant material to gain essential nutrients and energy - something necessary for powering such huge bodies!

Lengthy Necks

Sauropods were skilled at gathering food, and their long necks played a significant role in this. With necks that spanned enormous distances, they could stretch higher, lower, and wider than their competitors to reach the best available plants. These extended necks allowed them to obtain food that was out of range for most other creatures, similar to giraffes today.

Sauropods also had an advantage because of the reduced size of their heads. Having fewer teeth allowed them to swallow their food without chewing.

Skeletal Advantage

The secret behind the immense size of sauropods rested within their bones. Unlike other reptiles and mammals, their skeletons featured hollow bones filled with air.

By having air-filled bones, sauropods developed a much lighter skeletal system than other creatures. For instance, the heaviest animals that live today cannot support their weight outside water because of their dense bones' mass.

Sauropods' lighter skeletal system and neck bones allowed them to have longer necks and carry their weight with ease.

Bird-like Breathing System

The lighter bones of sauropods and theropods were a result of their bird-like breathing system. Their lightened bones contained air sacs that collaborated with their lungs, making their breathing very efficient.

Unlike humans and other mammals, whose oxygen intake is mainly through inhaling, the combination of air sacs and lungs allowed dinosaurs to receive oxygen even as they exhaled. This same breathing system enables geese to soar over the Himalayan mountains, where the oxygen levels are low.

Without this unique breathing system, sauropods would have been unable to grow to their colossal size or have necks of such epic proportions.

Notably, bar-headed geese can soar above the Himalayas, despite the dauntingly low oxygen levels thanks to their proficient breathing apparatus. Interestingly, both sauropods and theropods had similar respiratory techniques as these feathered navigators.

In addition to effective breathing, sauropods had a highly efficient metabolism, which facilitated the conversion of food into energy and waste. Contrary to their younger counterparts, these dinosaurs' metabolism decelerated as they aged, thus necessitating less food, proportionately, than mammals. With their vast stomachs, sauropods could digest food leisurely, enabling them to derive greater nourishment from plants that other herbivores could not digest entirely. This probably included conifer leaves, twigs, and perhaps cones.

Moreover, sauropods' massive build offered several advantages, from deterring predators to accessing otherwise unattainable food sources. Hence, during droughts or famines, sauropods could sustain themselves for more extended periods due to the water and fat stored in their colossal bodies.

However, being large also presented some drawbacks. For example, during prolonged periods of drought and scarcity of food and water, titanosaurs and other sauropods would find it challenging to sustain themselves due to their dietary requirements. Also, with their massive size came the propensity to overheat. Nevertheless, natural selection provided these dinosaurs with features such as a lightweight skeletal structure, which required less energy to move and other means of dissipating body heat, such as elongated necks and tails.

Although there is a chance of land animals, including modern ones, evolving towards giant proportions, it is unlikely they would match the size of sauropods. A specific set of characteristics unique to sauropods facilitated their immense growth, attributes that no other living animal possesses.

Lastly, though we no longer occupy the same space with sauropods and their ilk, we coexist with enormous creatures, including elephants, rhinoceroses, giraffes, polar bears, sharks, and whales.

However, these gargantuan creatures, much like titanosaurs, are at a heightened risk of facing significant challenges such as dwindling food sources, loss of natural habitat, and the harrowing effects of climate change. As a global community, we must unite and take proactive steps to ensure the flourishing existence of these contemporary behemoths.

Take a step towards safeguarding our planet's biodiversity by acquainting yourself with constructive actions that you can undertake. Discover the ways in which you can play a role in preserving our precious wildlife.