Brachiosaurus altithorax

Overview

Brachiosaurus, meaning "arm lizard," was one of the most magnificent dinosaurs ever to walk the Earth. Living during the Late Jurassic period (154-150 million years ago), this gentle giant could reach vegetation that no other dinosaur could touch, thanks to its incredibly long neck and unusual body plan.

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Taxonomy & Classification

• Clade: Sauropoda
• Family: Brachiosauridae
• Diet: Herbivorous
• Locomotion: Quadrupedal

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Physical Characteristics

Size & Build

• Length: 18-22 meters (60-72 feet)
• Height: Up to 13 meters (43 feet)—could look into 4th floor windows!
• Weight: 28,000-58,000 kg (31-64 tons)
• Neck Length: About 9 meters (30 feet)

The Giraffe Dinosaur

Brachiosaurus was unique among dinosaurs:

• Front legs LONGER than back legs (opposite of most sauropods!)
• This gave it an upward-sloping back like a giraffe
• Head was held high naturally—didn't need to raise it
• Could reach vegetation 9 meters (30 feet) above the ground!

Body Features

• Tiny head relative to body
• Nostrils on top of skull (scientists once thought it was aquatic!)
• Thick, powerful legs like pillars
• Relatively short tail for a sauropod

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Feeding & Diet

High-Rise Dining

Brachiosaurus had a unique feeding strategy:

• Could reach treetops other dinosaurs couldn't access
• Ate conifers, ginkgoes, and ferns
• Had to eat hundreds of kg of plants daily
• Didn't chew—swallowed food whole!
• Probably had stomach stones (gastroliths) to help digest

How Much Did It Eat?

• Estimated 400+ kg (880 lbs) of plants per day!
• That's like eating 8,000 salads daily
• Spent most of its time eating constantly
• Had to process huge amounts of low-nutrition plants

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Adaptations

Built for Height

• Air sacs in bones made it lighter (like birds today!)
• Special neck vertebrae were lightweight but strong
• Complex blood pressure system to pump blood to the brain
• Heart may have weighed 200+ kg (440 lbs)!

Breathing

• Had a bird-like respiratory system
• Air flowed in one direction through lungs
• Much more efficient than mammal lungs
• Helped support its enormous body

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Social Life

Herd Living

Brachiosaurus probably:

• Lived in herds for protection
• Adults protected young from predators
• May have migrated to find food
• Different ages may have fed at different heights

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Famous Appearance

Jurassic Park Star

Brachiosaurus became world-famous in Jurassic Park (1993):

• First dinosaur seen up close in the movie
• The iconic sneezing scene!
• Made audiences gasp at its sheer size
• Helped make sauropods popular again

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Discovery

Found in America and Africa

• First discovered in Colorado, USA in 1900
• Named by Elmer Riggs in 1903
• African relative (Giraffatitan) found in Tanzania
• Originally thought they were the same species

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Brachiosaurus vs. Other Giants

Dinosaur	Length	Height	Weight
Brachiosaurus	22m	13m	58,000kg
Diplodocus	33m	6m	16,000kg
Argentinosaurus	35m	7m	80,000kg
Giraffe (modern)	6m	5.5m	1,200kg

Brachiosaurus was the tallest dinosaur, though not the longest or heaviest!

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Predators?

Too Big to Attack?

Fully grown Brachiosaurus had few predators:

• Allosaurus lived in the same time/place
• Adults were probably too big to attack
• Young ones were vulnerable
• Size itself was their best defense

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Cool Facts

• Brachiosaurus could reach its head 4 stories high!
• Its heart pumped blood 6+ meters straight up to its brain
• One front leg bone was taller than an adult human!
• It took about 10 years to reach adult size
• Despite its size, its brain was only the size of a dog's
• Footprints over 1 meter wide have been found
• Scientists used to think it lived underwater—now we know it was fully terrestrial
• The name means "arm lizard" because its arms (front legs) were so long

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Brachiosaurus was the skyscraper of the dinosaur world—a gentle giant whose incredible height allowed it to browse treetops that no other creature could reach!