26 



JACK RABBITS OF THE UNITED STATES. '■ 



largely matters of opinion. Mr. H. P. Attwater states that the jack 

 rabbit on the southeast€frn coast of Texas is supposed to have only one 

 young at a birth. Dr. J. H. Clark, surgeon of tlie Mexican Boundary 

 Survey, notes that the species found along the Mexican border brings 

 forth but 2 or 3 young at a time, and these usually late in the summer. 

 The writer, in the 'Kern County Echo,' referred to above, says: "If 

 these rabbits breed every six weeks, as is asserted by many, or at the 

 outside, three times a year, * * * every farmer in this end of the 

 valley without a rabbit-tight fence will be comijelled to surrender his 

 ranch to the pests." 



As very little positive data seems to have been given by most 

 observers, recourse was had to the specimens in the collections of Dr. 

 C. Hart Merriam, the United States Department of Agriculture, and 

 the American Museum of Natural History,^ to supplement the few 

 published notes. Altogether about 50 specimens were available for 

 this purpose, consisting lirst of 15 adult females with young, which had 

 been examined in the field and a note made of the number of embryos 

 which each contained. These furnish the most accurate data possible 

 concerning the number of young. Tlie other specimens, 36 in number, 

 comprise rabbits less than half grown, and in some cases only a few 

 days old, which may be utilized to show roughly the dates of birth. 

 The data thus collected are shown in the following tables: 



Table showing number of Jack Babbits in a Utter {based on dissection of females with 



young). 



* Specimen in American Museum of Natural History, New York. 



The number of young as shown by these 15 specimens varies from 1 

 to C — never more; in fact it is probable that G is rather exceptional, 

 although found in three of the cases mentioned above. The average 

 obtained from the table is between 3 and 4 (3.5), but this result is prob- 

 ably not accurate. It will be noticed that all the cases of 3 young or 



' Through the kindness of Dr. .J. A. Allen, curator of mammals in the American 

 Museum of Natural History, New York, 1 have had au opportunity of examining the 

 jack rabbits in that collection. 



