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Whale Evolution: The Walking Whale

Timeline created by antoniefrankie in Science and Technology
Event Date: Event Title: Event Description:
465 realsize 1st Feb, 0500 The Pakecitus: 50-60 Million Years Ago One of the whale's earliest ancestors also belongs to the order cetacea, and is known as pakicetid. It lived near the prehistoric waters of Pakistan some 60 million years ago, and resembled a modern-day wolf -- with hooves. Looks can be deceiving, however, as there were certain traits in pakicetid that have carried over to today's whale: the unique position of the ear bones in the skull (which is only seen in cetaceans), a unique middle-ear bone, and triangular molars.
Whal 1st Dec, 0650 The Ambulocetus: About 50 Million Years Ago Ambulocetus was the next step in whale evolution - this "missing link" lived both on land and in the water, and was a carnivore approximately 9 feet long. Its hind legs were adapted to swimming, though it also walked on land. It also had triangular molars. Less noticeable but just as important, its inner ear bone had developed to be able to hear underwater.
Rodhocetus 1st May, 0710 The Rodhocetus: 45 Million Years Ago Rodhocetus was a semi-aquatic, primitive whale species that had the ankle bones of an artiodactyl, and the underwater hearing abilities of ambulocetus. It swam using its flipperlike feet and long tail which it used as a rudder. The nasal openings had begun to move up the skull, in what would eventually become the whale's signature spout. (This is known as a "nasal drift.") Its limbs could support them on land as well.
Basilosaurus 1st Feb, 0820 The Basilosaurus: 35-45 Million Years Ago Basilosaurus was a 50-foot-long sea mammal, though it originally had been mistaken for a lizard (Basilosaurus means "king lizard"). It swam like an eel, but its jawbone, ribs and and small hind limbs make it a mammal. It straddled two worlds; though it only lived in the water, it couldn't dive to any substantial depths, or could its hind limbs support it on land.
Wal 1st Feb, 0920 The Dorudon: 40 Million Years Ago The Dorudon was fully aquatic whales (like Basilosaurus, Dorudon had very small hind limbs that may have projected slightly beyond the body wall). They were no longer tied to the land; in fact, they would not have been able to move around on land at all.
Artist.impression.of.squalodon.by.anton.van 1st Feb, 1200 The Squalodon: 20 Million Years Ago Squalodon is an ancestor of the toothed whales, having retained its teeth from millions of years previous, during the time of pakicetid. They lived in warm waters.
Cetotherium 1st Feb, 1500 The Cetotherium: 15 Million Years Ago Cetotherium is an ancestor of the baleen, or filter-feeding whales (examples include the sperm whale, blue whale and humpback whale). It was smaller than the modern-day baleens, ranging between 10 and 20 feet long. They were hunted by megalodon, the infamous prehistoric shark that grew to 50 feet.
Screen%20shot%202012 02 01%20at%203.19.27%20pm The Modern Whale: Today Though many variations are part of the whales' family tree, today's whales are divided into two groups -- toothed and baleen.
Timespan Dates: Timespan Title: Timespan Description:
1st Feb, 0520
Whale Evolution: The Walking Whale Time Scale is in Millions and condensed.