Brachiosaurus - AZ Animals

B Species Profile Brachiosaurus

Brachiosaurus

The high-shouldered sky-browsing sauropod Daniel Eskridge/Shutterstock.com Encyclopedia / B Animals / Brachiosaurus Updated May 27, 2024 Index Overview Taxonomy Size Photos Did You Know Conservation Life Cycle Field Notes Humans Relations Species Article

Brachiosaurus Distribution

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Found in 1 country

🇺🇸 United States

Size Comparison

Human 5'8" Brachiosaurus 1 ft

Brachiosaurus stands at 18% of average human height.

At a Glance

Genus Overview This page covers the Brachiosaurus genus as a group. Stats below are general traits shared across the genus. Also Known As Brachiosaur, giraffe-necked dinosaur Diet Folivore Activity Cathemeral+ Lifespan 50 years Weight 60000 lbs Status Not Evaluated Did You Know?

The name means "arm lizard," referring to its unusually long forelimbs (longer than its hind limbs).

Scientific Classification

Genus Overview "Brachiosaurus" is not a single species but represents an entire genus containing multiple species.

Brachiosaurus is a genus of gigantic, long-necked sauropod dinosaurs characterized by proportionally long forelimbs and a high-shouldered body plan, making the neck base notably elevated compared to many other sauropods.

Kingdom Animalia Phylum Chordata Class Reptilia Order Saurischia Family Brachiosauridae Genus Brachiosaurus

Distinguishing Features

• Forelimbs longer than hind limbs, producing a forward-sloping back and high shoulders
• Very long neck adapted for high browsing
• Massive, columnar limbs supporting extremely large body size
• Member of Brachiosauridae (distinct from diplodocids like Diplodocus)

Physical Measurements

Imperial Metric Height 36 ft 1 in (29 ft 6 in – 42 ft 8 in) Length 72 ft 2 in (59 ft 1 in – 85 ft 4 in) Weight 38.6 tons (27.6 tons – 55.1 tons) Tail Length 32 ft 10 in (26 ft 3 in – 39 ft 4 in) Top Speed 12 mph Slow walker; bursts 10–20 km/h

Appearance

Primary Colors Gray Brown Tan Secondary Colors Cream Black Spotted Skin Type Reptilian, non-feathered integument. Likely covered in small, non-overlapping polygonal/pebbly scales, potentially with larger scales around pressure points (shoulder/hip/limb). Direct skin impressions for Brachiosaurus are limited; this is generalized from sauropod evidence rather than genus-specific material. Distinctive Features

• Long-forelimbed, high-shouldered brachiosaurid body plan: forelimbs longer than hindlimbs, elevating the shoulder and the base of the neck compared to many other sauropods.
• Very tall browsing posture: elevated neck base and large overall height, implying access to high foliage in Morrison Formation ecosystems.
• Brachiosaurus adults are thought to be about 18–26 m long, 25,000–50,000+ kg, with shoulder heights around 6–7 m and head heights about 12–13 m; numbers vary.
• Skull/nares arrangement typical of brachiosaurids as reconstructed: relatively elongated skull with large external narial opening positioned high on the skull; exact soft-tissue profile unknown.
• Columnar limbs with robust, weight-bearing feet; proportionally long forelimbs contribute strongly to the 'giraffe-like' silhouette.
• Many classic Brachiosaurus pictures used African bones now placed in Giraffatitan (like 'B.' brancai). North American Brachiosaurus (Morrison Formation) may differ, so whole-genus proportions are unsure.
• Genus-level: large plant-eater that likely browsed high but could feed at many heights; probably used bulk fermentation. Social life is unclear, maybe loose groups or more organized herds that change with age and resources.
• Lifespan (broad, inferred for gigantic sauropods): on the order of decades, plausibly ~30-60+ years, with substantial uncertainty; growth to adult size likely took many years and may have varied with environment and individual condition.

Photo Gallery

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Did You Know?

The name means "arm lizard," referring to its unusually long forelimbs (longer than its hind limbs).

Brachiosaurus lived in the Late Jurassic and is known from North America's Morrison Formation, a hotspot for famous sauropods.

Its high-shouldered build likely let it browse higher vegetation than many other sauropods sharing its ecosystem.

Many classic museum mounts and pop-culture "Brachiosaurus" depictions were actually based on the African dinosaur now called Giraffatitan.

Even within a single genus, size estimates vary widely because remains are incomplete and scaling methods differ among studies.

Brachiosaurus is not known from a definitive skull in the type material; many commonly depicted brachiosaurid skull features (including high-set nostrils) come primarily from related taxa such as Giraffatitan rather than directly from Brachiosaurus.

Unique Adaptations

• Disproportionately long forelimbs creating a "giraffe-like," high-shouldered posture-an uncommon body plan among sauropods.
• A tall, forward-tilted trunk profile that likely shifted the feeding envelope upward compared with many contemporaries.
• Very large body size with columnar limbs adapted for supporting immense weight over long distances.
• Sauropod-style tooth and jaw design suited to cropping large amounts of plant material efficiently (with processing happening in the gut rather than by chewing).

Interesting Behaviors

• High browsing was likely common: the elevated shoulder and long forelimbs would raise the neck base, making tall vegetation more accessible than for many level-backed sauropods.
• Feeding height probably varied by age and circumstance: juveniles/subadults would have browsed lower, while large adults could reach higher canopy levels.
• Likely spent much of the day foraging across floodplains and river-margin woodlands; movement and habitat use probably shifted seasonally with plant availability.
• Herding is plausible but not proven for the genus: sauropod trackways and bonebeds in general suggest group travel in some sauropods, but direct Brachiosaurus-specific evidence is limited.
• Reproduction was almost certainly via egg-laying like other non-avian dinosaurs; nesting behaviors are inferred broadly for sauropods rather than known directly for Brachiosaurus.

Cultural Significance

Brachiosaurus is a famous 'gentle giant' in museums and movies, shown by tall skeletons and a movie image of a sauropod that ate from tall trees. It helps teach how scientific names changed—many old specimens are now Giraffatitan.

Myths & Legends

Naming tale (1903): paleontologist Elmer S. Riggs coined "Brachiosaurus" ("arm lizard") to highlight its unusually long forelimbs-an origin story often retold in dinosaur history accounts.

Museum-mount legacy: for much of the 20th century, the most famous "Brachiosaurus" displays and illustrations were strongly influenced by the African species later renamed Giraffatitan, creating a long-running public identity mix-up.

A famous movie's first sight of a towering Brachiosaurus made it a symbol of ancient giants, even though the real Brachiosaurus is North American and the film used general brachiosaurid features.

Classification legend in the public mind: "Brachiosaurus vs. Giraffatitan" is frequently cited in exhibits and books as a modern scientific saga-how new analyses can split familiar dinosaurs into separate genera.

Conservation Status

NE Not Evaluated

Has not yet been evaluated against the criteria.

Population Unknown

Looking for a specific species?

Brachiosaurus

Brachiosaurus altithorax

This is the type species and the one most often meant in popular and scientific usage when the genus name "Brachiosaurus" is used without qualification.

• Genus-wide size generalizations (not a single-individual claim): commonly reconstructed at roughly ~18-26 m total length and ~30,000-60,000+ kg, with substantial uncertainty because the genus is currently represented by limited, fragmentary-to-partial material.
• Typical brachiosaurid proportions: longer forelimbs than hindlimbs produce a high-shouldered stance and elevated neck base, supporting interpretations of frequent mid-to-high browsing compared with many other sauropods.
• How long Brachiosaurus lived is unknown. Studies of very large sauropods suggest decades-long lives (about 30–60+ years), but it likely varied with environment and individual growth.
• A large land herbivore that ate many plants, likely moving in loose or age-based groups; feeding height, use of riverine woodland versus open floodplain, and herd size changed with local plants and seasons.

View Brachiosaurus Profile

You might be looking for:

Brachiosaurus altithorax

70%

Brachiosaurus altithorax

Type species of Brachiosaurus from the Late Jurassic of North America; the best-supported species within the genus.

Giraffatitan

25%

Giraffatitan brancai

Famous African 'Brachiosaurus' from Tendaguru; now generally placed in a separate genus (formerly Brachiosaurus brancai).

Brachiosauridae (brachiosaurids)

5%

Brachiosauridae

The broader family of long-forelimbed sauropods related to Brachiosaurus (often conflated with it in popular media).

Life Cycle

Birth 20 hatchlings Lifespan 50 years

Lifespan

In the Wild 30–70 years

Reproduction

Mating System Polygynandry Social Structure Aggregation Group Breeding Pattern Seasonal Fertilization Internal Fertilization Birth Type Internal_fertilization

Brachiosaurus mating is inferred, not seen. Likely polygynandry: many males and females mated at seasonal gatherings (aggregation_group). They used internal_fertilization and laid eggs. Pair bonds were short. No evidence of helper care. Confidence is low.

Behavior & Ecology

Social Herd Group: 8 Activity Cathemeral, Diurnal Diet Folivore High-canopy conifer and ginkgo-like foliage Seasonal Migratory 200 km

Temperament

+1 more Show less Generally non-aggressive herbivore; primary defenses likely size, vigilance, and group spacing rather than active combat Cautious and reactive to threats; adults likely stood ground more often than juveniles Juveniles likely more skittish and reliant on grouping Intraspecific tolerance likely moderate in feeding areas, with occasional displacement/spacing behavior when competing for browse

Communication

low-frequency rumbles or resonant calls Inferred; potentially useful over long distances shorter grunts/snorts or bellow-like calls Inferred; may relate to alarm, contact, or mating contexts visual displays via head/neck posture and body orientation High-shouldered build may enhance signaling ground-borne vibrations from footfalls/stomping as a potential alert/contact signal Inferred tactile contact such as nudging between conspecifics Inferred, especially adult-juvenile interactions chemical cues/olfaction for individual or reproductive status recognition Inferred; indirect evidence

Habitat

Show all Show less Woodland Forest Grassland Shrubland River/Stream Lake Pond Wetland Swamp +3 Biomes: Temperate Forest Temperate Grassland Savanna Freshwater Wetland Terrain: Plains Riverine Valley Plateau Elevation: Up to 1,500 m

Ecological Role

Megaherbivorous primary consumer and high-browser that influenced Jurassic plant communities

Top-down control of woody vegetation via heavy browsing pressure (especially on mid-to-upper canopy foliage) Nutrient cycling through large-volume dung deposition and carcass inputs Habitat modification by opening canopy gaps and creating/trampling pathways that affected understory structure Potential long-distance movement of nutrients across landscapes via foraging and defecation Indirect support of food webs by providing resources for decomposers and scavengers through dung and occasional mortality events

Diet Details

Other Foods: High canopy foliage Cycad and bennettitalean fronds Woody browse Understory plants Reproductive plant parts

Human Interaction

Domestication Status

Wild

Brachiosaurus was never domesticated. It went extinct in the Late Jurassic, tens of millions of years before humans existed, so there is no domestication history. Human interaction is limited to modern scientific and cultural activities such as fossil discovery, excavation, research, and museum display.

As a Pet

Not Suitable as Pet

Legality: Not applicable as a pet because Brachiosaurus is extinct; keeping a live individual is impossible. Fossil ownership/trade legality varies widely by country/state (often regulated; export and collection may require permits, and some fossils are state property).

Care Level: Expert Only

Purchase Cost: Lifetime Cost:

Economic Value

Uses: Paleontology and academic research Museum and educational exhibition Tourism and cultural heritage Media/entertainment and merchandising Fossil/replica markets (regulated/variable legality) Products:

• Museum mounts and exhibitions (original or cast)
• Research value (scientific publications, grants, collections)
• Replica skeletons, casts, and educational models
• Documentary/film/game depictions and licensing/merchandise tie-ins
• Fossil preparation, curation, and conservation services
• Limited legal fossil sales/trades in some jurisdictions; replicas more common than originals

Relationships

Predators 4

Allosaurus Allosaurus fragilis Torvosaurus Torvosaurus tanneri Ceratosaurus Ceratosaurus nasicornis Saurophaganax Saurophaganax maximus

Related Species 5

Giraffatitan Giraffatitan brancai Shared Family Sauroposeidon Sauroposeidon proteles Shared Family Cedarosaurus Cedarosaurus weiskopfae Shared Family Lusotitan Lusotitan atalaiensis Shared Family Camarasaurus Camarasaurus lentus Shared Order

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Giraffatitan Giraffatitan brancai Shares a high-shouldered, long-forelimbed brachiosaurid body plan; interpreted as a high-browsing sauropod occupying upper-canopy feeding niches. Sauroposeidon Sauroposeidon proteles An extremely tall sauropod with adaptations for high browsing; often compared in neck and shoulder height and ecological role as a megaherbivore that fed above many contemporaries. Camarasaurus Camarasaurus lentus Common Morrison Formation megaherbivore; overlaps as a large-bodied bulk-feeding sauropod but likely differed in preferred feeding height and plant selection, being more mid-level/general browsing rather than strongly high-browsing. Diplodocus Diplodocus carnegii Shared broad environments with other large sauropods and partitioned plant resources; typically reconstructed as a lower browser, feeding from ground to mid-level vegetation compared with higher-browsing brachiosaurids.

Types of Brachiosaurus

1

Explore 1 recognized types of brachiosaurus

Brachiosaurus Brachiosaurus altithorax

As one of the most recognizable dinosaurs, the popular Brachiosaurus was a well-known herbivore that liked to munch on leaves with its long, long neck.

Brachiosaurus actually refers to an entire genus of dinosaurs that lived during the Late Jurassic period. These dinosaurs have made appearances in everything from kids’ toys to blockbuster movies.

Species, Types, and Scientific Names

Brachiosaurus long neck dinosaur is a genus of the Brachiosauridae family. The most common species within this genus is B. altithorax. It is part of the Sauropoda clade, also known as Sauropods. This clade includes other long-necked dinosaurs.

All of these dinosaurs were herbivores and lived very similar lives. There are Sauropods of all different sizes. Many even lived in the same regions at the same time.

Brachiosaurus was a dinosaur and part of the Chordata phylum. This refers to animals, including modern-day species. They were ultimately part of the Kingdom Animalia, the Animal Kingdom, just like today’s humans.

Brachiosaurus

Kingdom	Animalia
Phylum	Chordata
Clade	Sauropoda
Family	Brachiosauridae
Genus	Brachiosaurus
Species	Brachiosaurus altithorax

Description and Size

Brachiosaurus long neck dinosaur is a genus in the Brachiosauridae family. They are one of the better-known Sauropods. The Sauropoda clade includes other herbivore dinosaurs that walk on four legs and have long tails and necks.

Brachiosaurus is known for its long neck. This is one of its most easily identified features. Based on specimens of the Brachiosaurus altithorax, estimates of its overall length are up to 85 feet. This accounts for length from the top of their head all the way to the tip of their tail.

They stood between 30 and 40 feet tall. This helped them reach vegetation that was much higher than other dinosaurs of their day. Brachiosaurus was roughly the height of a modern four-story building!

The Brachiosaurus long-neck dinosaur walked on four legs. Its front legs were longer than the back legs. Brachiosaurus is often referred to as the “arm lizard.” These longer front legs helped support their neck, which was longer and heavier than their tail. Longer front legs also helped Brachiosaurus reach higher into the trees for food. Brachiosaurus’ neck formed an S-shape, with the top curving forward and the base curving back to connect to its body. The middle section was relatively straight.

It had a relatively small head and brain compared to its large size. Brachiosaurus could weigh up to 28 tons. But due to their small legs relative to their long necks and large mid-sections, Brachiosaurus couldn’t actually run very fast.

Brachiosaurus nostrils were on top of their heads. This initially supported the idea that Brachiosaurus lived in water. Now, scientists believe that Brachiosaurus lived on land even though their nostrils were on the top of their bodies.

Diet – What Did Brachiosaurus Eat?

Despite their giant size, Brachiosaurus subsisted entirely on plants. These herbivores ate leaves and other vegetation, often from high up in the trees. Like other Sauropods, Brachiosaurus ate plants while standing on four legs. Brachiosaurus could reach plants that were as high as 30 feet off the ground. Researchers believe that they favored high vegetation that was 16 feet or higher off the ground.

Brachiosaurus probably had to eat a lot to maintain its size. Some scientists believe that its long neck evolved to let it eat and digest complex plants that were high up in the trees. Other herbivores that lived alongside Brachiosaurus, including other Sauropods, ate from lower trees and branches.

Some of the fiercest competition for Brachiosauruses was likely getting enough food. They had to fight off other Sauropods and other Brachiosauruses to eat enough. Scientists theorize that the various species of Sauropods developed at different heights so that there was enough vegetation for each of them to eat their fill.

Habitat – When and Where It Lived

The Brachiosaurus long neck dinosaur lived during the Late Jurassic period, between 156 and 145 million years ago. Many other Sauropods, including the Apatosaurus and Diplodocus, also lived during this time period. They probably lived through the Cretaceous Period.

Initially, scientists believed that Brachiosaurus lived in the water. They thought that their size was too large to be supported by their legs and bodies on land. However, based on further analysis of their feet as well as their bones, researchers now believe that Brachiosaurus roamed on land.

Based on discoveries of fossils, Brachiosaurus lived in North America. Many were found in the Morrison Formation in the Southwest United States. Scientists believe that this region was lush during the time of the dinosaurs, providing plenty of water from rivers and plant life to eat. Savannahs with ferns and conifer trees provided food for Brachiosaurus and other herbivores.

Threats And Predators

Many dinosaurs, even carnivores, probably left Brachiosaurus alone due to their large size. It would have taken a lot of smaller dinosaurs to take down an enormous Brachiosaurus.

Large carnivores that lived during the Jurassic Period included the Allosaurus and Dilophosaurus. The Tyrannosaurus rex did not actually evolve until after the Jurassic Period after the Brachiosaurus was no longer roaming the earth. Allosaurus was the main predator of the Jurassic Period. These carnivores were smaller than the better-known T. rex, although they were just as formidable of hunters.

Injury, illness, and lack of food and water were always threats to dinosaurs during this time. This included Brachiosaurus long neck dinosaur. While their environment was rich in natural resources that helped them survive, the young and old dinosaurs were the most vulnerable.

Discoveries and Fossils – Evolution

Brachiosaurus was first discovered in 1900. A team of researchers found fossils in Colorado in the Grand River Valley. They eventually classified these fossils as Brachiosaurus in 1903. The dinosaur was named by Paleontologist Elmer Riggs. https://a-z-animals.com/animals/location/north-america/united-states/colorado/

Other fossils discovered in the late 1800s were later determined to be Brachiosaurus fossils, specifically a skull. It wasn’t until 1998 that the link was made, however. These first discoveries were made in Colorado, although not identified as the first Brachiosaurus discoveries until over 100 years later.

The Morrison Formation in the Southwest United States is a rock formation where many fossils from the Jurassic Period were discovered, including Brachiosaurus. The rock formation stretches from Montana all the way to New Mexico. So many dinosaur fossils have been discovered here that the National Park Service designated it as the Dinosaur National Monument.

Brachiosaurus long neck dinosaur is one of the rarer finds in the Morrison Formation. However, scientists do know that they lived during the time period and in the same location as many dinosaurs that are plentiful in that rock formation. They have discovered large Brachiosaurus fossils in the rock dating to the Jurassic Period.

In 2019, scientists found a Brachiosaurus humerus fossil in the Morrison Formation. It weighed nearly 1,000 pounds and was over 6 feet long. Because its location was so hard to reach, the team had to use a pair of Clydesdale horses to pull it out of the earth. The horses were barely taller than the bone itself. The fossil was taken to the Utah Field House of Natural History State Park Museum.

Extinction – When Did It Die Out?

The latest fossils found of the Brachiosaurus long-neck dinosaur show that it lived in the late Jurassic Period, probably around 145 million years ago. Most scientists believe that it lived into the Cretaceous Period and went extinct after a massive meteor hit the earth. Called an extinction event, the meteor caused the climate to shift so much that plants and animals were unable to survive the ice age and went extinct.

Similar Animals

Many other Sauropods lived during the Jurassic Period and shared common features with the Brachiosaurus. These include:

• Apatosaurus: These Sauropods were a bit smaller than Brachiosaurus and likely ate vegetation that was lower to the ground. They still had long necks and tails. They also walked on four legs just like the Brachiosaurus.
• Diplodocus: Another Sauropod of the Jurassic Period, Diplodocus was longer and taller than Brachiosaurus. It weighed less, however.

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Brachiosaurus Pictures

View all of our Brachiosaurus pictures in the gallery.

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Sources

1. National Geographic Kids: Brachiosaurus / Accessed May 31, 2022
2. National Geographic Kids: Apatosaurus / Accessed May 31, 2022
3. NPS: Diplodocus / Accessed May 31, 2022
4. Smithsonian Mag: Brachiosaurus discovery / Accessed May 31, 2022
5. NPS: Morrison Formation / Accessed May 31, 2022

About the Author

Katie Melynn Wood

Katie is a freelance writer and teaching artist specializing in home, lifestyle, and family topics. Her work has appeared in At Ease Magazine, PEOPLE, and The Spruce, among others. When she is not writing, Katie teaches creative writing with the Apex Arts Magnet Program in Anne Arundel County, Maryland. You can follow Katie @katiemelynnwriter. Connect:

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Brachiosaurus FAQs (Frequently Asked Questions)

When did Brachiosaurus live?

The Brachiosaurus was alive during the Late Jurassic period, between 156 and 145 million years ago. Researchers believe that it lived all the way through the Cretaceous period and went extinct following a specific extinction event that caused an ice age.

How big was a Brachiosaurus?

Brachiosaurus was very long and tall. It measured around 85 feet from its head to the tip of its tail. It stood around 30-40 feet tall. It stood on four legs, although it could reach its neck high up into the trees for food.

View Brachiosaurus Photos

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