GIANT SOUTH AMERICAN RIVER TURTLES

      I recently became aware, by a TV program of giant South American river turtles living in the large Orinoco and Amazon Rivers in the tropical Amazon Basin of northern South America.  And what impressed me the most about these giant river turtles is the annual gathering of hundreds of female turtles on gigantic flats of soil during the annual drought when river water levels drop dramatically.     

     Those female turtles come together on the flats to lay their eggs at one time in the two and a half foot holes they dug in the soil with their back feet, one per turtle, on a bit higher part of the large, drying flats.  Each female lays about a hundred eggs in the pit she dug.  Digging a nursery hole a little uphill helps insure the turtle embryos don't drown before they hatch.  Perhaps, in the past, through trial and error, the river turtles that may have deposited eggs to close to the river have no descendants today because too many of their young drowned while still in their eggs when the river water level rose too soon.  But turtles that laid eggs on higher ground have descendants today because their young weren't nearly so likely to drown.   

     And all those hundreds of female giant river turtles laying eggs at once on the flats assure there will be safety in great numbers when their thousands of two inch, same-age baby turtles hatch all at once and scramble in groups to the river their mothers emerged from two months ago.  Still, black vultures consume some of the baby river turtles on the flats and crocodiles ingest more at the river shorelines.  

     The nesting habits of giant South American river turtles is similar to that of sea turtles on sandy beaches off the oceans.  Thousands of female sea turtles come out of the ocean at once and slide laboriously up the beach away from the water to dig out holes in the sand with their back feet; one pit per turtle.  Masses of hatchling sea turtles have a better chance of reaching the ocean without being eaten because of the mass nesting all at once.  

     Female giant South American river turtles grow up to three and a half feet and 200 pounds.  Males of the species are smaller.  Both genders are dark all over, with yellow-orange patches on their faces.

     These river turtles pile on each other on trees fallen into the rivers.  There they sun themselves to warm up enough to have the energy to look for food and mates.  They mostly ingest fruit, seeds, algae and other plant materials.  

     Today these turtles are endangered because of habitat loss, dams, over-harvesting of eggs and adults, and water pollution.  But many local people are helping to restore the numbers of these turtles, and their habitats.  Eggs are gathered and hatched in enclosed areas to eliminate predation of the hatchlings.  And those baby turtles are housed and fed in safe places where predators can't get them until they are big enough to be released into their ancestral rivers.  Though currently down in numbers from their peak of population, restoration practices will help them increase their numbers.