Basilosaurus cetoides

Overview

Basilosaurus cetoides was one of the largest and most fearsome predators of the ancient seas, living approximately 40-34 million years ago during the Late Eocene epoch. This "king of the ancient whales" was the state fossil of Alabama and Mississippi, and its serpent-like body could stretch up to 20 meters long—longer than a modern humpback whale!

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Taxonomy & Classification

• Order: Archaeoceti (ancient whales)
• Family: Basilosauridae
• Diet: Carnivorous
• Type: Early whale

Despite its name meaning "king lizard," Basilosaurus was definitely a mammal, not a reptile!

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Physical Characteristics

Size & Build

• Length: 17-20 meters (56-66 feet)
• Weight: Approximately 15,000 kg (33,000 lbs)
• Body Shape: Extremely long and snake-like

Unique Features

• Serpentine body much longer and thinner than modern whales
• Tiny vestigial hind legs (proof of land-dwelling ancestors!)
• Multiple types of teeth for different purposes
• Small flippers compared to body size
• Probably had tail flukes like modern whales

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Those Tiny Hind Legs!

Living Proof of Evolution

Basilosaurus cetoides had something incredible:

• Tiny functional hind limbs about 60 cm (2 feet) long
• Had knees, ankles, and toe bones!
• Way too small for walking
• May have been used during mating
• Shows that whales evolved from land animals
• Descendants of creatures like Pakicetus that walked on land

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Hunting & Diet

Apex Predator of the Eocene

Basilosaurus cetoides was a top predator:

• Hunted fish, sharks, and other whales
• Preyed on smaller whales like Dorudon
• Fossil evidence shows bite marks on Dorudon skulls!
• Had different teeth:
  • Pointed front teeth for grabbing
  • Serrated back teeth for cutting

Feeding Behavior

• Probably an ambush predator
• Hunted in shallow, warm seas
• Could open jaws very wide
• May have shaken prey to tear off pieces

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Swimming Style

Not Like Modern Whales

Basilosaurus moved through water differently:

• Undulated side-to-side like an eel or sea snake
• Modern whales move tails up and down
• Long body helped it move through water
• Not built for deep diving
• Stayed in shallow coastal waters

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Where It Lived

Ancient Seas

Basilosaurus cetoides swam in:

• The warm, shallow seas covering the Gulf Coast region
• Modern-day Alabama, Louisiana, Mississippi
• When these areas were underwater!
• Ancient Tethys Sea environment

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A Naming Mistake

King Lizard?

The name Basilosaurus was an accident:

• First fossils discovered in Louisiana in 1834
• Scientists thought it was a giant marine reptile
• Named it "king lizard" (Basilosaurus)
• Later realized it was a whale!
• By then, the name had to stay (scientific naming rules)

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Basilosaurus vs. Modern Whales

Feature	Basilosaurus	Modern Whales
Body Shape	Long, snake-like	Streamlined, robust
Hind Legs	Tiny but present	Completely internal
Swimming	Side-to-side undulation	Up-and-down tail motion
Echolocation	Probably not	Yes (toothed whales)
Brain Size	Relatively small	Very large

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Discovery & Importance

American History

Basilosaurus has a special place in paleontology:

• First described by Richard Harlan in 1834
• Some fossils were used as furniture before people knew what they were!
• Albert Koch once assembled a fake 35-meter "sea serpent" from multiple specimens
• Now the official state fossil of Alabama (1984) and Mississippi (1981)

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Cool Facts

• Basilosaurus was so long, early scientists thought it was a sea serpent!
• Its vertebrae were once used as andirons (fireplace stands) by settlers!
• Some fossils show shark bite marks—evidence of scavenging after death
• The tiny hind legs had all the bones of a land animal's leg, just miniaturized
• Basilosaurus shared its world with giant sharks and other marine predators
• It could open its mouth to about 75 degrees—wide enough to grab large prey
• The species name "cetoides" means "whale-like"

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Basilosaurus cetoides was a serpent of the ancient seas—a link between the whales that walk and the whales that swim, with tiny legs to prove it!