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LAND ANCESTORS OF WHALES. "Although early whale fossils had been known at least as early as the 1830s, they were often mistaken for giant marine reptiles, as evidenced by the genus name Basilosaurus (Greek for ‘king lizard’), a long, snake-like whale from the Late Eocene [38–34 million years ago (Mya)]." https://www.researchgate.net/profile/Michael_Mcgowen/publication/275671338_A_Whale_of_a_Tale/links/558bce1608ae681f47160178.pdf View in LinkedIn

TRANSITION TO LAND. "Many amniote groups (e.g. sauropterygians, squamates, cetaceans, sirenians, pinnipeds) made the evolutionary transition from a fully terrestrial to a semi- or fully aquatic life. This required major morphological and physiological changes that are best developed in the most specialized aquatic forms, like extant cetaceans and sirenians, which now live totally independent of the terrestrial environment." http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118409 View in LinkedIn

LAND BIRTH. "Preservation of an intact near-term fetal skull and partial skeleton indicates that birth in early archaeocetes involved a single calf that was born head-first as in land mammals, not tail-first as in living whales. This, in turn, indicates that birth almost certainly took place on land during this phase of early whale evolution." http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004366 View in LinkedIn

BIRTH ORIENTATION. "Cephalic presentation at birth is generally held to be advantageous on land as it enables a newborn to breath during labor. Caudal presentation at birth, in contrast, is generally held to be advantageous at sea as it may reduce the risk of drowning. Caudal presentation may also hold an advantage in water, because it orients the newborn calf to swim parallel to the mother rather than away from her." http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004366 View in LinkedIn