On my last day in Australia, I was taken on a brief excursion to Walyunga National Park by Hugh Morrison. Together with Brian Cleaver and Derek Mead-Hunter he is doing there interesting research on Bothriembryon indutus.
About 8 years ago Hugh accidentally found a spot where B. indutus occurred in great numbers. He decided to study their movements by labelling individual snails and rocks under which he found them. This way he discovered that most snails aestivated each year under the same rock.
He also started to take measurements of individual snails to track their growth. They don’t grow evenly but in ‘bursts’ when the season is favourable (i.e. rainy); during dry years there is hardly any growth. By extrapolation from the data already obtained, the estimation is that it takes 10 years from hatching to adult stage and the maximum age is estimated at 40 years. When we visited the site, several snails were found depositing their eggs in the ground.
Another observation was the finding of many shells without the top whorls. Hugh explained that not only empty shells but also living snails are used by young ones as source of calcium. Recycling of calcium in this calcium-poor environment leads thus to a form of cannibalism???