SIZE VARIATION 



i^nn^J^ published references pertaining to the naximum snout-vent 

 length of Rana tigrina are extant. Issac and Rege (1975) recordld on 

 unsexed mdiv^ual (unquestionably female) itBasSing 175 n^^ouSv^nt 

 length f rom Banbay In western India, adult females occasioSlly SSed 

 160 xm snout-vent length. Males are invariably of lesser snSSt-L^ 

 length although Mansukhani and Murthy (1970) claimed Sat m^es^aL 



length, m Rajasthan, India. These data, obviously a size reversal of 

 ^!^ norphometrics, are not corroborated by published observations 

 Murthy 1968 noted that females attain a larger size (178 iT^ 188 rim) 

 than males (143 nin - 165 mn) when sexually irature (Madras, Mia) 



Eight population saitples, randomly selected, of Rana tigrina frcm 

 diverse districts of Bangladesh suggest that the i;ean ^^t^^J^^ 

 ?L^.^! '^ significantly less than those of the Indian conspeci- 

 fers although carparative data are minimal. 



Males. --The mean size-cohort of males is 101-110 irni (24% of all 

 males examined) although 23.1% of all males examined are in the 

 91-100 irm size-cohort. Thus, approximately 50% of the males examined 

 nieasure from 91 imi to 110 mm in snout-vent length. Males greater than 

 (Tab]S 1"°''^"'^''^ ^^"^^ "^""^ "°t encountered in the population sanple 



Males are the first emergents at the onset of the nonsoonal rains. 

 Wiose males of larger size are imttediately removed from the reproduc- 

 tively active populations by the field collectors. The vociferous calls 

 and breeding colors attract the attention of predators, hunan and oth- 

 ers. The breeding stock, therefore, is composed of smaller males. 



In the population samples obtained in early May and early June, 

 the mean size-cohorts of mles are 121-130 nm and 131-140 inn. The mean 

 size-cohorts of later populations decline to 91-100 inn and 101-110 nm. 



OA ia ^f^J-fs.— The mean size-cohort of females, 111-120 mn, includes 

 ^4.1% of all females examined. The size-cohort 121-130 mn contains 

 1: o ,.« ^ females examined. Less than 1% of the 915 females examined 

 150 nm snout-vent length. 



The mean size-cohorts of females in population sanples of early 

 ^fey and early June are 111-120 mn and 131-140 mn. Later population sam- 

 ples, with slight fluctuation, decline to nean size^xshorts of 

 111-120 mn and ultimately to 91-100 mn. 



Females anerge from hibernation after males and thence enter re- 

 productive activities. The nean size-cohorts of the females, with 

 slight fluctuation, exhibit a decline from early June (131-140 nm) . The 

 fluctuation in mean size-cohort may be attributable to local climatic 

 conditions, primarily the onset of the nonsoonal rains. 



