22 December 2005, 10:33 AM ET
Christmas trees and other conifers seem to have lousy plumbing systems and should be extinct. A new study reveals how they thrive.
03 August 2005, 12:21 PM ET
Humans, not warming climate, killed off the giant mammals that roamed North America during the last Ice Age.
16 June 2005, 04:00 AM ET
The New Zealand moa took ten years to reach full size, making it vulnerable to hunters.
18 April 2005, 02:29 AM ET
One million years ago, elephants and their cousins roamed the five major continents of the earth. Then humans came along.
14 April 2005, 10:02 AM ET
Low levels of oxygen made for a sluggish recovery from the Great Dying 250 million years ago.
07 April 2005, 03:43 AM ET
A new report lists the 25 most endangered primates and says several are in a grave state.
08 March 2005, 01:30 AM ET
And now the bad news: There's not much anyone can do about it.
19 January 2005, 08:20 PM ET
Heat, lack of air probably led to the Great Dying, rather than an asteroid impact.
02 December 2004, 01:30 AM ET
New evidence that the Great Dying was not caused by a space rock.
08 November 2004, 04:00 AM ET
It couldn't have been so dark and cold, a researcher says.
12 October 2004, 03:00 AM ET
Today's endangered species lists hide thousands of plants and animals that will also become extinct if their host species disappear, new research shows.