How Humans Lost Their Tail, Twice
By Jen Viegas, Seeker | December 6, 2016 08:55am ET
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How Humans Lost Their Tail, Twice
A 5-week-old human embryo showing a teensy prenatal "tail."
Credit: Tatiana Shepeleva, Shutterstock.com
Humans can't seem to keep a tail, suggests new research that finds our early ancestors lost tails not just once, but twice.
The findings, published in the journal Current Biology, not only help explain why people don't wag dog-like tails, but they also shed light on why we all have a tailbone and begin life with an actual tail that gradually disappears.
"Fleshy tails go all the way back to the earliest vertebrate ancestors and are found in very young embryos, so it would be very difficult to get rid of them entirely without causing other problems," author Lauren Sallan told Seeker. "As a result, both fishes and humans have had to stunt growth instead, leaving a buried, vestigial tail much like the legs of whales."
http://www.livescience.com/57101-how-humans-lost-their-tail.html
