A savannah monitor lizard.
By THE NEW YORK
TIMESPublished: December 16, 2013
Biologists
have found that savannah monitor lizards extract oxygen from the air when
inhaling and when exhaling — a characteristic, known as unidirectional
breathing, that is most associated with birds. The discovery of this trait in
lizards, reported in the journal Nature, raises questions about when and why it evolved. Either it
developed in the 270-million-year-old common ancestor of lizards, birds and
alligators (which were also recently found to practice unilateral breathing) —
much longer ago than originally thought — or it developed independently in each
evolutionary branch. As for why it evolved, the long-held theory that it aided
flight in birds appears to need updating.
Posted by
:Gauri Shah
Faculty
Biotechnology
BII
