Spinosaurus aegyptiacus

Overview

Spinosaurus, meaning "spine lizard," was the largest carnivorous dinosaur ever known—even bigger than T. rex! Living approximately 100 to 94 million years ago during the Late Cretaceous period in North Africa, this bizarre predator was unlike any other dinosaur, spending much of its life hunting in rivers like a giant crocodile.

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Taxonomy & Classification

• Clade: Theropoda
• Family: Spinosauridae
• Diet: Carnivorous (primarily fish)
• Locomotion: Bipedal on land, swimming in water

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Physical Characteristics

Size & Build

• Length: 15-18 meters (50-59 feet)—longer than T. rex!
• Weight: 7,000-20,000 kg (estimates vary)
• Skull Length: 1.75 meters (5.7 feet)
• Height of Sail: Over 1.6 meters (5 feet) tall!

The Incredible Sail

Spinosaurus's most famous feature was its massive back sail:

• Made of elongated vertebrae spines covered in skin
• Up to 1.6 meters (5+ feet) tall
• Possible functions:
  • Display for attracting mates
  • Temperature regulation
  • Fat storage like a camel's hump
  • Making it look bigger and scarier

Crocodile-Like Skull

• Long, narrow snout like a crocodile or gharial
• Conical teeth perfect for gripping slippery fish
• No serrations on teeth (unlike most carnivorous dinosaurs)
• Nostrils positioned high on the snout for breathing while partially submerged

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The Swimming Dinosaur

Aquatic Adaptations

Spinosaurus was built for life in the water:

• Paddle-like tail for swimming (discovered in 2020!)
• Dense bones helped it sink and control buoyancy
• Short hind legs compared to other theropods
• Webbed feet possibly for paddling
• Pressure sensors in snout for detecting fish underwater

How It Hunted

• Stood in shallow water like a heron
• Swept its head through the water to catch fish
• Could swim after prey using its tail
• Also ate pterosaurs, crocodiles, and other animals

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Spinosaurus vs. T. rex

Feature	Spinosaurus	T. rex
Length	15-18m	12-15m
Weight	7-20 tons	7-9 tons
Diet	Mainly fish	Other dinosaurs
Habitat	Rivers, swamps	Forests, plains
Arms	Large and useful	Tiny!
Lifestyle	Semi-aquatic	Fully terrestrial

They never actually met! Spinosaurus lived 30 million years before T. rex.

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Tragic History

Lost and Found

The Spinosaurus story has drama:

• First fossils found in Egypt in 1912
• Studied by German scientist Ernst Stromer
• Original fossils destroyed in WWII bombing of Munich
• For decades, we only had drawings and notes
• New fossils found in Morocco in 2014 revolutionized our understanding
• The tail discovery in 2020 proved it was a swimmer!

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Habitat

A Prehistoric Paradise

Spinosaurus lived in a unique environment:

• River systems and coastal swamps of North Africa
• Warm, humid tropical climate
• Shared its world with:
  • Giant sawfish as big as cars
  • Massive crocodiles
  • Other large predatory dinosaurs
• This area is now the Sahara Desert!

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Pop Culture

Movie Star

• Featured as the villain in Jurassic Park III
• Shown defeating a T. rex (scientifically unlikely since they never met!)
• Has become increasingly popular as we learn more about it
• One of the most mysterious and debated dinosaurs

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Cool Facts

• Spinosaurus was the only known swimming dinosaur
• It could hunt both on land and in water
• Its sail made it the tallest dinosaur when measured from back to ground
• Some scientists think the "sail" might have been more like a hump
• New discoveries are still changing what we know about it!
• If it were alive today, it could swim in the ocean

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Spinosaurus was the ultimate aquatic predator—a dinosaur that broke all the rules and lived a life more like a giant crocodile than any of its relatives!