12 THE BROWN HAT IN THE UNITED STATES. 



of its history, but it is supposed to be a native of Egypt, where it is 

 still abundant. It is almost as remarkable as the brown rat for its 

 wandering propensities, and it is probably quite as common on sea- 

 going ships. It has established itself in seaports in many parts of 

 the world, mainly in warm climates, and is common near the coast 

 in southern parts of the United States. The Biological Survey has 

 specimens from North Carolina, Georgia, Florida, Alabama, Missis- 

 sippi, Texas, Arizona, and California. In the last-named State it is 

 abundant in the Sacramento Valley. The species is known from 

 Lake Drummond, Va., and from Cuba, the Bermudas, Trinidad, 

 San Domingo, Costa Rica, Nicaragua, Mexico, and Hawaii. It 

 occurs also in many parts of South America, where it is often the 

 dominant species. 



In most parts of the United States the rat common about houses 

 and barns is the brown rat. It is larger and more robust than either 

 the black rat or the roof rat, and differs from them considerably in 

 habits. Unlike them, it almost always burrows in the ground under 

 buildings and in loose soil along hedges and river banks. This habit 

 affords better protection from enemies and, combined with the 

 animal's greater ferocity, has enabled it to supplant the other species 

 in temperate latitudes; but in the warmer parts of America it has 

 not always been able to do this, and the roof rat appears to be -most 

 numerous in many localities. The house mouse escapes the brown 

 rat by taking refuge in crevices and other retreats too small for its foe 

 to enter. 



The brown rat inhabits most of the thickly populated parts of 

 America. North of Panama it occurs from the Isthmus to the Yukon 

 Valley and to Greenland, except on the interior table-lands and per- 

 haps in a few sections of the South. Between the Rocky Mountains 

 and the Sierra it is confined almost entirely to towns along the rail- 

 roads. The Biological Survey is without records of its presence in 

 Nevada, Utah, Wyorhing, or Idaho. The ability of the species to 

 withstand extreme cold is proved by the fact that it flourished in 

 latitude 78° 37' north, on board the ship Advance of Doctor Kane's 

 second Grinnell expedition during the two winters of icebound 

 experience. It has been able to adapt itself also to the continuous 

 low temperatures of cold-storage plants in many of our cities. 



HISTORY OF THE BROWN RAT. 



The early history of the brown rat is practically unknown. The 

 species is generally supposed to be of Asiatic origin, but we have no 

 positive knowledge as to its native country. Various modern writers 

 have asserted that it came originally from Persia or India. But Mr. 



« In the principal Asiatic seaports the brown rat is said to be often found closely 

 associated with the other two forms. 



