10 Facts About Brachiosaurus, the Giraffe-Like Dinosaur

01
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How Much Do You Know About Brachiosaurus?

brachiosaurus
Nobu Tamura.

The long-necked, long-tailed Brachiosaurus wasn't the biggest sauropod ever to walk the earth, but it still ranks among the most popular, alongside Diplodocus and Apatosaurus. On the following slides, you'll discover 10 fascinating Brachiosaurus facts.

02
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Brachiosaurus Had Longer Front than Hind Limbs

brachiosaurus
Berliner Morgenpost.

Rather disappointingly, considering its long neck, long tail and enormous bulk, the late Jurassic Brachiosaurus (Greek for "arm lizard") was named after a less impressive feature--the relatively long length of its front, compared to its hind, limbs, which endowed this dinosaur with a giraffe-like posture. This was clearly a dietary adaptation, as its longer front limbs allowed Brachiosaurus to reach the high branches of trees without unduly straining its neck (there's even some speculation that this sauropod could rear up occasionally on its hind legs, like a giant grizzly bear!)

03
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An Adult Brachiosaurus Could Live to Be 100 Years Old

brachiosaurus
Dmitry Bogdanov.

As a general rule, the bigger and slower an animal is, the longer is its life span. The enormous size of Brachiosaurus (up to 85 feet long from head to tail and 40-50 tons), combined with its presumed cold-blooded metabolism, meant that healthy adults reached the century mark on a regular basis--especially since a full-grown Brachiosaurus would have been virtually immune to danger from predators (like the contemporary Allosaurus) once it aged out of its vulnerable childhood and teenage years. 

04
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Brachiosaurus Was Probably a "Homeotherm"

brachiosaurus
Wikimedia Commons.

How did a dinosaur as big as Brachiosaurus regulate its body temperature? Paleontologists speculate that sauropods took a long time to warm up in the sun, and an equally long time to dissipate this built-up heat at night--resulting in a steady state of "homeothermy," that is, a relatively constant body temperature at any given time of the day. This still-unproven theory is consistent with sauropods possessing a cold-blooded (i.e, reptilian), but not a warm-blooded (i.e., mammalian), metabolism. (Contemporary meat-eating dinosaurs like Allosaurus, on the other hand, may have been genuinely warm blooded).

05
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The "Type Specimen" of Brachiosaurus Was Discovered in 1900

brachiosaurus
Elmer Riggs (left) working on the Brachiosaurus holotype (Wikimedia Commons).

In 1900, a fossil-hunting crew from Chicago's Field Museum of Natural History discovered a near-complete dinosaur skeleton (missing only its skull; see next slide) in the Fruita region of western Colorado. The expedition chief, Elmer Riggs, named the type fossil Brachiosaurus; ironically, this honor should have belonged to the famous American paleontologist Othniel C. Marsh, who nearly two decades before before had incorrectly classified a Brachiosaurus skull as belonging to the distantly related Apatosaurus. (See more about the fossil history of Brachiosaurus).

06
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The Skull of Brachiosaurus Was Easily Detached from its Neck

brachiosaurus
Wikimedia Commons.

One of the odd things about dinosaurs like Brachiosaurus is that their tiny-brained skulls were only loosely attached to the rest of their skeletons--and thus were easily detached (either by predators or by natural erosion) after their deaths. In fact, it was only in 1998 that paleontologists conclusively identified a skull discovered by the 19th-century paleontologist Othniel C. Marsh (see previous slide) as belonging to Brachiosaurus, rather than Apatosaurus. (By the way, this same loose-skull problem also bedeviled titanosaurs, the lightly armored sauropods of the Cretaceous period).

07
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Brachiosaurus May Have Been the Same Dinosaur as Giraffatitan

Giraffatitan
Giraffatitan, a long-necked relative of Brachiosaurus (Sergey Krasovskiy).

The picturesquely named Giraffatitan ("giant giraffe") lived in late Jurassic northern Africa rather than North America, but in all other respects it was a dead ringer for Brachiosaurus, except for the fact that its neck was even longer. Even today, paleontologists are unsure whether Giraffatitan merits its own genus, or is best classified as a separate species of Brachiosaurus, B. brancai. (The exact same situation holds, by the way, with the giant "earthquake lizard" Seismosaurus and another famous genus of North American sauropod, Diplodocus.)

08
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Brachiosaurus Was Once Believed to Be a Semiaquatic Dinosaur

brachiosaurus
An early depiction of Brachiosaurus (public domain).

A century ago, naturalists speculated that Brachiosaurus could only have supported its 50-ton weight by walking along the bottoms of lakes and rivers and thrusting its head out of the surface, like a snorkel, to eat and to breathe. Later, though, this theory was discredited when a detailed mechanical analysis demonstrated that the high water pressure of an undersea habitat would quickly have suffocated this giant beast--though that hasn't kept some people from claiming that the Loch Ness Monster is really a 150-million-year-old Brachiosaurus, or some other type of sauropod! 

09
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Brachiosaurus Wasn't the Only "Brachiosaurid" Sauropod

qiaowanlong
Qiaowanlong, a brachiosaurid sauropod (Nobu Tamura).

The exact classification is still a matter of some dispute, but generally speaking, a "brachiosaurid" sauropod is one that mimics Brachiosaurus' general body shape: long neck, long tail, and longer front than hind limbs. Some well-known brachiosaurids include Astrodon, Bothriospondylus and Sauroposeidon, and there's also some evidence pointing to an Asian brachiosaurid, the recently discovered Qiaowanlong. The other main category of sauropods is the "diplodocids," that is, dinosaurs closely related to Diplodocus.

10
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Brachiosaurus Wasn't the Only Sauropod of Late Jurassic North America

diplodocus
Diplodocus coexisted with Brachiosaurus (Alain Beneteau).

You might think a dinosaur as big and imposing as Brachiosaurus would "crowd out" its niche on the floodplains of late Jurassic North America. In fact, though, this ecosystem was so lush that it could accommodate numerous other genera of sauropods, including Apatosaurus and Diplodocus. Most likely, these dinosaurs managed to coexist by evolving different feeding strategies--perhaps Brachiosaurus concentrated on the high branches of trees, while Apatosaurus and Diplodocus held out their necks like the hoses of giant vacuum cleaners and feasted on low-lying shrubs and bushes.

11
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Brachiosaurus Is One of the Most Popular Movie Dinosaurs

brachiosaurus
Brachiosaurus, as seen in Jurassic Park (Universal Studios).

No one will ever forget that scene in the original Jurassic Park when Sam Neill, Laura Dern and company feast their eyes on a herd of Brachiosaurus, peacefully and majestically munching leaves in the distance. Even before Steven Spielberg's blockbuster, though, Brachiosaurus had been the go-to sauropod for directors trying to create a convincing Mesozoic landscape, and it still makes unexpected guest appearances elsewhere (for example, did you know that the creatures mounted by the Jawas in the "enhanced" Star Wars: A New Hope were modeled on Brachiosaurus?)