NOTES ON A SPECIES OF RAT (MUS TOMPSONII, 

 RAMSAY), NOW INFESTING THE WESTERN POR- 

 TION OF N.S.W. 



By K. H. Bennett. 



These rats made their appearance in the Ivanhoe district in 



February of the present year, but at that time only as scattered 



individuals. By the middle of Api'il the whole country west of 



the main road from Booligal to Wilcannia was swarming with 



them, all travelling in a southerly direction ; and so numerous 



were they that on loose sandy spots, and along dry dusty roads 



(trending south), the tracks of horses, sheep, and vehicles were 



nightly as completely obliterated by the foot-prints of the passing 



swarms, as if the surface of the soil had been swept with a broom. 



On one occasion at an out-station on Kilfera Run, a large number 



of sheep had been put through a gate near the house on the 



afternoon of my arrival, and of course thousands of tracks or 



foot-prints of sheep were visible on the dry dusty soil through and 



around the gate ; but the next morning not a track was to be seen, 



and the whole gror.nd was as smooth as if swept by a broom or a 



sti'ong wind, although the night was perfectly calm. A close 



insjjection, ho'vever, soon revealed the cause which was entirely 



owing to the swarms of rats that had passed during the night, 



millions of tiny foot-prints comj)letely smoothing the dusty soil. 



These journeys were always performed during the night, the rats 



liiding in the day time in rabbit-warrens, deep fissures in the 



ground, or amongst dense masses of herbage. Their food consists 



chiefly of seeds of various kinds, and the soft succulent stems of a 



]ilant locally known as " pigweed," which owing to the good season 



is extremely plentiful; but I am inclined to think that their diet is 



not exclusively confined to vegetable substances, as I have been 

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