Elasmosaurus platyurus

Overview

Elasmosaurus, meaning "thin-plated lizard," had the longest neck of any animal ever! Living during the Late Cretaceous period, about 80 million years ago, this incredible marine reptile could have used its 7-meter neck to snatch fish from a distance no other predator could match—like a living submarine with a crane for a head!

---

Taxonomy & Classification

• Order: Plesiosauria
• Family: Elasmosauridae
• Diet: Carnivorous
• Lifestyle: Fully aquatic

Elasmosaurus gave its name to an entire family—the elasmosaurids!

---

Physical Characteristics

Extreme Proportions

• Total length: 10-14 meters (33-46 feet)
• Neck length: About 7 meters (23 feet)—HALF its body!
• Weight: 11,000-14,000 kg (12-15 tons)
• Neck vertebrae: 72 bones—the MOST of any animal!

Body Features

• Tiny head compared to body
• Long, sharp teeth that interlocked
• Four large flippers for "underwater flight"
• Relatively short tail
• Barrel-shaped body

---

The Record-Breaking Neck

Longest Neck Ever!

Animal	Neck Length	Vertebrae
Elasmosaurus	7 meters	72
Giraffe	2.4 meters	7
Brachiosaurus	9 meters	~16
Swan	1 meter	22-25

Elasmosaurus had 10 times more neck bones than a giraffe!

---

Hunting with That Neck

The Element of Surprise

The long neck was a hunting weapon:

• Body stayed hidden below
• Only the small head approached prey
• Fish didn't see the danger coming
• Could strike sideways rapidly
• Like a hidden fishing rod!

What It Ate

• Fish of all sizes
• Squid and ammonites
• Small marine reptiles
• Anything it could grab and swallow

---

Could It Raise Its Head?

The Swan Pose Myth

Old pictures showed Elasmosaurus with neck raised high out of water:

• Scientists now know this was WRONG!
• The neck couldn't bend that way
• It would be too heavy to lift
• Probably kept neck mostly horizontal
• Movies and old art got it backwards!

---

Four-Flipper Swimming

Unique Locomotion

Elasmosaurus swam unlike any living animal:

• All four flippers used for propulsion
• Moved like "flying underwater"
• Could hover, turn, and maneuver
• Very agile despite huge size
• Flippers couldn't work on land!

---

Famous Mix-Up!

The Head-Tail Confusion

Elasmosaurus has a famous story:

• First assembled in 1868
• Scientists put the head on the WRONG END!
• Paleontologist E.D. Cope made the mistake
• Rival O.C. Marsh corrected him
• Started the famous "Bone Wars" rivalry!
• The error embarrassed Cope for life!

---

Living in the Western Interior Seaway

An Inland Sea

Elasmosaurus lived in:

• The Western Interior Seaway
• A sea that split North America in two!
• Stretched from Gulf of Mexico to Arctic
• Warm, shallow waters
• Alongside mosasaurs and giant fish

---

Giving Birth

Live Young

Like other plesiosaurs:

• Gave birth to live babies
• Couldn't come on land to lay eggs
• Babies were born swimming
• May have cared for young

---

Discovery

Kansas Seas

• First found in Kansas, USA in 1867
• Kansas was once underwater!
• Named by E.D. Cope in 1868
• Many specimens found since
• Now known from excellent fossils

---

Cool Facts

• Had 72 neck vertebrae—the most of ANY animal ever!
• The famous "head on wrong end" mistake sparked a scientific feud
• Scientists once thought it could raise its head like a swan—now we know it couldn't
• Swallowed stones to help digest food or control buoyancy
• Its teeth interlocked when closed—perfect fish traps
• Lived when Kansas was under a shallow sea
• Could NOT survive on land—would be crushed by its own weight
• Inspired the Loch Ness Monster legend!

---

Elasmosaurus was the ultimate stealth hunter—a marine reptile with an impossibly long neck that let it strike before prey even knew danger was near!