Skip to main content
  1. News
  2. Science & Space

New research finds live birth began 175 million years ago

See also

Live birth began in the ancestors of snakes and lizards at least 175 million years ago according to new research published by Alex Pyron, Robert F. Griggs Assistant Professor of Biology in the Columbian College of Arts and Sciences at the George Washington University, on Dec. 17, 2013, in the journal Ecology Letters.

More Photos

This discovery radically changes some preconceptions about evolution. Most biologists thought that an animal that evolved from producing eggs to produce live birth never returned to producing eggs but the new research invalidates that concept.

Pyron based his conclusion on an analysis of modern snakes and lizards and an examination of the DNA of the ancestors of modern snakes and lizards including the animal’s most ancient ancestors. Twenty percent of modern snakes and lizards give birth to live offspring while the other 80 percent lay eggs.

The fossil record includes a few lizards from the Cretaceous Period that have embryos. The embryo indicates a live birth.

The conclusion is that snakes and lizards switched from laying eggs to live birth several times over the millions of years that reptiles have been on Earth.

Pyron plans a similar examination of mammal ancestors that may reveal an egg laying mammal from the distant past. Five modern mammals lay eggs including the platypus.

Advertisement

News

  • Mt. Everest avalanche
    Disaster strikes Mt. Everest as at least 12 people were killed in an avalanche
    Video
    Watch Video
  • Most Earthlike planet discovered
    The Kepler telescope has discovered the most Earthlike, possibly habitable planet yet
    Space News
  • Easter crosses create debate
    Easter crosses spark a debate of separation of church and state in Ohio
    Headlines
  • Chelsea Clinton is preggers
    Former first daughter Chelsea Clinton is pregnant with her first child
    Headlines
  • Stanley Cup playoffs
    The battle for Lord Stanley's Cup is on, don't miss a minute of playoff action
    Sports
  • Ukraine discussed amongst U.S., E.U., Russia
    The U.S., E.U. and Russia agree on ways to diffuse the tension in Ukraine
    Video
    Watch Video

Related Videos:

  • LADEE mission ends with impact on lunar surface
    <div class="video-info" data-id="518201429" data-param-name="playList" data-provider="5min" data-url="http://pshared.5min.com/Scripts/PlayerSeed.js?sid=1304&width=480&height=401&playList=518201429&autoStart=true"></div>
  • Kepler-186 Sol Comparison
    <div class="video-info" data-id="518200618" data-param-name="playList" data-provider="5min" data-url="http://pshared.5min.com/Scripts/PlayerSeed.js?sid=1304&width=480&height=401&playList=518200618&autoStart=true"></div>
  • Purchase Your Pair of Google Glass Today
    <div class="video-info" data-id="518193403" data-param-name="playList" data-provider="5min" data-url="http://pshared.5min.com/Scripts/PlayerSeed.js?sid=1304&width=480&height=401&playList=518193403&autoStart=true"></div>

User login

Log in
Sign in with your email and password. Or reset your password.
Write for us
Interested in becoming an Examiner and sharing your experience and passion? We're always looking for quality writers. Find out more about Examiner.com and apply today!