Nature. Long Sleepers.

Waikato Times, Volume XXIII, Issue 1893, 23 August 1884, Page 6 (Supplement)

Nature. Long Sleepers.

Even among v^m blooded animals, like the beai and dormice, hibernation actually occurs to a very considerable decree ; but it is far more common and more complete among cold-blooded creaimes, whose bodies do not need to be kept heated to the same degiee, and with whom, accordingly, hibernation becomes almost a complete torpor, the breathing and the action of the heart boing still further reduced to very noasiy zero. Mollusks in particular, like oystez* and mussels, lead very monotonous aud uneventful lives, only varied as a lule by the welcome change of being cut out of their shells and eaten alive ; and their powers of living without food under advereo ciicuinstances are realiy very remarkable. Fresh water snails and mussels in cold weather bury themselves in the mud ponds or rivers, and land snails hide themselves in the ground or under moss and leaves. The heart then ceases perceptibly to beat, but respiration continues in a very faint degree. The common garden snail closes the mouth of his shell, when he wants to hibernate, with a slimy covering, but he leaves a very small hole in it somewhere, so as to allow a little air to get in and keep up his breathing to a blight amount. My experience has been, aowever, that a great many snails go to sleep in this way atfd never wake up again. Either they get frozen to death or else the respiration falls so low that it never picks itself up pioperly when Spring returns. In warm climates ifc is during the Summer that mollusks aud other mud haunting creatures go to sleep, and when they get well plastered round with clay they almost approach in tenacity of life tne mildest recorded specimens ;f the toad in a hole. For example, take the following cases which extract, with needful simplifications, from doctor Woodward :— "In June, 1850, a living pond mussel, which had been more than a year out of water, was sent to Mr. Gray from Australia. The big pond snails of the tropics have been found alive in logs of mahogany imported from Honduras; and M. Caillaud carried ;ome from Egypt to Paris, packed in sawdust, indeed, it isn't easy to ascertain the limit of

their endurance, for Mr. Laidlay, having placed a number in a drawer for this very purpose, found them alive after five years 1 torpidity, although in the warm climate of Calcutta. The pr6tty snails called cyclostomas, •which have a lid to their Shells, are well known to survive imprisonment for many months ; but in the ordinary open mouthed land snails such cases are even more remark' able. Several of the enormous tropical snails often used to docorate cottage mantelpieces, brought by Lieutenant Greaves from Valparaiso, revived after being packet!, soma for thirteen, others for twenty months. In 1840 Mr. Pickering received from Mr. Wollaston a basket of Madeira snails (Hi twenty or thirty different kinds) three-fourths of which proved to be alive, after several months' confinement, including a sea voyage. Mr. Wollaston has himself recorded the fact th&t specimens of two Madeira snails survived a fast and imprisonment in pill boxes of two years and a half duration, and that large numbers of a small species, brought to England ftft the same time, were all living after being inclosed in a dry bag for a year and a half."*