Tuesday, July 6, 2010

Speaking of Cloacae

Roxie Laybourne, who spent her career at the National Museum in Washington, was one of my mentors.  Among her claims to fame was that she was the only person who could identify the sex of a living Whooping Crane.

Whooping Crane sex is important.  The Fish and Wildlife Service took eggs from wild nests in Canada and hatched them in Maryland.  They bred these birds to build a captive flock, thereby assuring survival of the species in case anything happens to the wild birds (oil spills, late season hurricanes?). 
The problem is that Whooping Cranes form life-long pair bonds.  If you accidentally try to mate two males, they may form a homosexual pair bond, and you have just wasted two very valuable birds.  Roxie developed a machine, basically an ophthalmoscope with tweezers, to peer into a Whooping Crane's vent and into the cloaca (see last post).  Male birds have two testes, but females normally have but one ovary.  Thus, the male cloaca has five internal openings (two sexual ducts, two urinary ducts, and the digestive tract); the female has four (only one sexual duct).  By counting those openings, Roxie knew the sex of those birds.  (Of course, the cranes were not crazy about having their cloacae examined.  Wildlife technicians caught the captive birds and placed them in special straight jackets before Roxie went to work.)

No comments:

Post a Comment