SEVENSEAS Marine Conservation & Travel Issue 21, February 2017 - Page 111

1 Topic : 5 Facts

How well do you know the ocean?

This regular feature will help acquaint you with our blue planet.

Topic: Cetaceans Over Time

Every whale, dolphin, and porpoise is the descendant of land-dwelling mammals that

completed their return to the sea around 40 million years ago.

Like all mammals, the cetaceans are warm-blooded, give birth to live young, the mothers

produce milk to sustain their young, and they even have sparse hair at some point in

their development.

The cetaceans are most closely related to the artiodactyls which are represented by

cows, pigs, hippos, sheep, giraffes, and camels.

The transition from land to sea took approximately 12 million years, as measured by thecurrent fossil record.

The division between baleen whales and toothed whales happened around the same time, about 30 million years ago during the late Eocene.

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SEVENSEAS - 111

February 2017 - Ocean Literacy