Advertisement.

EnchantedLearning.com is a user-supported site.
As a bonus, site members have access to a banner-ad-free version of the site, with print-friendly pages.
Click here to learn more.

Join Enchanted Learning
Site subscriptions last 12 months.
Click here for more information on site membership.

As low as $20.00/year (directly by Credit Card)
Site members have access to the entire website with print-friendly pages and no ads.
(Already a member? Click here.)

Zoom Whales
ALL ABOUT WHALES!
What is a Whale? Whale Information Sheets Simple Whale Print-outs Extreme Whales Whale Myths Whale Evolution

PRIMITIVE WHALES AND WHALE EVOLUTION

Primitive whales evolved during the early Eocene period, at least 53 - 54 million years ago. Fossil remains indicate that whales evolved from hoofed land mammals - perhaps the shore-dwelling, hyena-like Mesonychid that started a returned, bit by bit, to the sea roughly 50 million years ago.

Another possible step in whale ancestry is the otter-like Ambulocetus, an extinct mammal the size of a sea lion, 10 feet (3 m) long and about 650 pounds. Its limbs allowed it to swim and could also support it on land. It had long, powerful jaws with shark-like teeth, a small brains, and a pelvis fused to its backbone (like land-dwelling mammals but unlike whales).

Himalayecetus subathuensis is the oldest-known whale, about 53.5 million years old. Its fossilized jawbone and teeth were found in the Simla Hills of northern India, in the foothills of the Himalayan mountains. This area was underwater (in the Tethys sea) during the Tertiary period (when India was an island off Asia). This whale may have spent some of its time on land.

The later Pakicetus, a primitive whale with pointed teeth like Mesonychid and a pinched brain case like Ambulocetus, had a water-adapted inner ear but still had four limbs. It had nostrils located at the front of its head; it had no blowhole!

Rodhocetus, even more whale-like, had four short limbs (the femur or thigh bone was only 8 inches - 20 cm long) but had a whale-like body and its pelvis was no longer fused to the backbone. It had a long snout with many teeth.

Dorudon atrox, another early whale, was about 20 feet (6 m) long. Its arms were small, flattened flippers. The rear limbs were only about 4 inches (10 cm) long. It also had a long snout with many teeth.

Basilosaurus, a very primitive, extinct whale, had a tiny head and pointed snout with teeth, unlike modern-day whales which have large heads and a blunter snout. It was about 65 ft (20 m) long.

Baleen whales evolved from the toothed whales during the Oligocene Epoch, roughly 30 million years ago. The earliest-known baleen whale was Aetiocetus, which still had all its teeth, but it also had a loose jaw hinge like later baleen whales.

Advertisement.

EnchantedLearning.com is a user-supported site.
As a bonus, site members have access to a banner-ad-free version of the site, with print-friendly pages.
Click here to learn more.

Join Enchanted Learning
Site subscriptions last 12 months.
Click here for more information on site membership.

As low as $20.00/year (directly by Credit Card)
Site members have access to the entire website with print-friendly pages and no ads.
(Already a member? Click here.)

Zoom Whales
ALL ABOUT WHALES!
What is a Whale? Whale Information Sheets Simple Whale Print-outs Extreme Whales Whale Myths Whale Evolution

Information Sheets About Whales
(and other cetaceans)

Just click on a cetacean's name to go to that information sheet.

BELUGA WHALE

BLUE WHALE

BOTTLENOSE DOLPHIN

BOWHEAD WHALE

GRAY WHALE

HUMPBACK WHALE

KILLER WHALE

MINKE WHALE

NARWHAL

ORCA

RIGHT WHALES

SPERM WHALE



Enchanted Learning®
Over 20,000 Web Pages.
Sample Pages for Prospective Subscribers

Overview of Site
What's New
Enchanted Learning Home
Monthly Activity Calendar
Books to Print
Site Index
K-3
Crafts
K-3 Themes
Little Explorers
Picture dictionary
PreK/K Activities
Rebus Rhymes
Stories
Writing
Cloze Activities
Essay Topics
Newspaper
Writing Activities
Parts of Speech
Fiction
The Test of Time 		Biology
Animal Printouts
Biology Label Printouts
Biomes
Birds
Butterflies
Dinosaurs
Food Chain
Human Anatomy
Mammals
Plants
Rainforests
Sharks
Whales
Physical Sciences
Astronomy
The Earth
Geology
Hurricane
Landforms
Oceans
Tsunami
Volcano
 Languages
Dutch
French
German
Italian
Japanese (Romaji)
Portuguese
Spanish
Swedish
Geography/History
Explorers
Flags
Geography
Inventors
US History
Other Topics
Art and Artists
Calendars
Crafts
Graphic Organizers
Label Me! Printouts
Math
Music

Click to read our Privacy Policy

E-mail Busy Little Brains
CD-ROM

Enchanted Learning Search

First search engine with spelling correction and pictures!
Search EnchantedLearning.com for all the words:
Enter one or more words, or a short phrase.
You can use an asterisk * as a wild-card.


Advertisement.



Advertisement.


Copyright ©1998-2009 EnchantedLearning.com ------ How to cite a web page