82 ftot t'~K*»rhm Witurabst Vo! J& 



THE SWALLOWING OF STONtS BY ANIMALS 



By Alfred A. Bakfr* 

 Presidential Address to FN-CY, May 95 1955 



Thi? paper ouginated itoJM jLJ| investigation into the origin of certain 

 highly polished pebbles found near Tnvcrloch. So;ith Gippsland. Victoria 

 The possibility of these having been sw-allowcd by animals, and so polished, 

 was considered, but a search through literature on the suhjpet a»d an 

 examination of viol'ished pebbles available and known to have been swallowed 

 Uy animals, clearly indicated that the South GivtMmd pebbles were polished 

 by otter means. Data on this is to be published at £ later date. 



That stones have been swallowed and still are swallowed by various 

 animals is now (irmly established, but 1he reason for thtS still remains some- 

 what uncertain A review of papers written on the subject over the last 

 hundred years, shows that this phenomenon :s not altogether a rarity, and 

 it does, allow some conclusions to be tormtd on the problem 



Stones, as found in the stomachs of living animals or associated with their 

 skeletal remains, are referred to in literature as "gizzard stones", ^OoraCh 

 r-tones" and "gastroliths'*. 



The word "gastrolith" was ftr#t used in 185*1 by Muyne, in fi.rpoi. Lev. 

 Castrolithus; he defined it as "a stone or calculus in the stomach". In 1880, 

 Huxley used the word when describing crayf.sh; he writes: "there are 

 found at the side of the stomach, two lenticular calcareous masses, which 

 are known as 'crab's eyes', or gastrohihs , 



Roth these refer to calcareous structures which form on the inner walls 

 ftj the stomach ot freshwater crayfish, prior to the moult, and are a storehouse 

 of rrtatertai which assists in the footling ot lite new carapace. These ostro- 

 liths, or "yabbie stones'* as they are called in Victoria, differ entirely, both 

 ill appearance and structure, front those which have been swallowed. VV'icland 

 ( 1906) introduced the word "gastfolirh" when referring to rrnnrU prbWes 

 found associated with dinosaurian remains and thought to have been swallowed 

 by them. 



Swallowed atones may be of nny variety ot i:atuial rock, eiihcr anguine 

 nr rounded in shape, and may have a polished or dull surface. 



"Stones" occurring in the organs of animals, including man, have no 

 connection with lite subject ot this paper. 



The following animals have been recorded as stone-swallowers*. 

 Extinct reptile* — Klastnosaurufc. Flcsiosanros, Trinacrontcrum, Polycotylus. 



Mauisauru;-, Peloueustes, Cloasaur, AtJantoNaurus, Barosauru:, Tcleos- 



aurus. 

 hiring reptile*— Crocodile. Alligator, Lizard, 

 Living mflmtt|3i$— Seals (Crab-eater, Fjord, Elephant f/url, Sea licm. 



Dolphin, Porpoise, Walrus 

 Living fishes — Shark (Baking), Uofc-ruh. Cod. Hake,, Stmp-ray. Trout 

 Extinct bird;— -ProkOotus, Pcxophaps (Solitaire), Dinorni.s (\foa) f Geny- 



arnis. 

 Living birds— Penguins (Emperor, King, Adekei. Mutton-bird. Ostrich, 



F.nm, Cockatoo. Parrot. Chough, Plover, 5nH, Pigeon* Grebe. Ib»* (large 



Quantity of "yabbie-stoncs'') , Dotterel; not including over sixty species 



having swallowed gravel, grit, or sajid, 



Extinct Resiles 



Karly geologists searching tor reptilian remains of the Mesozoic period, 

 both m £n«laml and in North America, iVccjuenily ir-unn pebble? in ciose 

 association Willi the bouts. Considerable discussion arose at the time, as to 

 the possibility fyt tlie&e pebbles having been associated with the living animal. 



•Curator. Otology tlejwrtmenL, University M Melbourne 



