The evolution of whales beggining with their ancestor the 'Cetacea'. They are the descendants of terrestrial animals that returned to the sea.

Whales are known to be descendants of land mammals with physical characteristics: bones in their flippers which resemble the forelimbs of land mammals, vertical movement of their spines which resembles a running terrestrial animal, and the fact that they must breathe air.

Whale evo

This phylogenetic tree describes the evolution of the whales, we can see that there ancestors were different in many facts.

In 1693, John Ray penned his realization that whales were mammals, not fish. William Henry Flower recognized that whales have vestigial features characteristic to land mammals in 1883, confirming that whales evolved from terrestrial animals rather than being the ancestors of today's land mammals.

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This photo describes an early whale originally classified as a reptile

But scientists initially came up with a wide variety of hypotheses as to what animals were ancestral to whales. In 1859 Charles Darwin suggested that whales were descended from bears. {C {C

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This photo describes an articulated skeleton of Indohyus, a partially aquatic early cetacean

The discovery of Indohyus' cetacean properties was an accident: the man who originally discovered the species had died, and his widow passed the skeletons on to Thewissen.One of Thewissen's technicians accidentally broke open a skull one day, revealing the characteristic inner ear of a whale. About the size of a cat, Indohyus was conspicuously herbivorous.

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This photo describes 'the early' whale. This is an articulated composite skeleton of Ambulocetus, the "walking whale"

Ambolucetus was an amphibious mammal that lived in warm, brackish river deltas along the shore of the Tethys Sea.Also like modern cetaceans, Ambulocetus could hear well underwater and had a nasal adaptation that permitted it to swallow underwater.

thumb|356px|left|This video shows some water beats.