FIELD-XOTES OX MAMMALS IN THE SOUTHERN SUDAN. 341 



21. Field-Notes on some Mainmals in the Baln*-el-Gebel, 

 Southern Sudan. Bv Major J. Stevenson Hamilton, 

 C.M.Z.S. 



[Received October 18, 1919 : Read Xovemlier 18, 1919.] 



(With Chart.) 



It should be noted that my intimate personal experience 

 extends only to the area between Bor and Shambe, and from 

 these points eastwards to a distance of 80 miles, N. and IST.E. of 

 Shambe 60 miles, and west of the river about 20 miles. It is 

 onl}'^ in this area that I have been resident. As regards the 

 region between Mongalla and Bor, I have spent onlj^ two months 

 of the dry season there, and south of Mongalla I know the 

 country only from occasional short visits. 



Thiang {Damaliscus tiang Heugh). 



West bank. — Through the flat countiy from Lado northwards 

 to Shambe. 



East ba,nk. — From a little south of Bor northwards to the limit 

 of the area considered. 



Found east of the Nile in much greater numbers than to the 

 west. Country probably more suital>le. The great open plains 

 in the ISFuer, and in the west of the Dinka country seem especially 

 fitted to their liabits. The type found west of the river is of 

 much deeper coloration and contrasted markings than that occur- 

 ring west of it, forming perhaps a different local variety. 



During the dr}^ months Thiang may be seen on these plains in 

 countless numbers. In the vicinity of water-pools hei'ds of from 

 1000 to 2000 are common, and two or three such herds may be in 

 sight at one time. 



The habits of the Thiang appear more akin to those of the 

 Blesbuck than to those of its other cousin the Tsessobe, which 

 latter is never found in droves and seldom far from forest or 

 savannah country. 



In the wet season, however, the Thiang are driven from most of 

 those great plains by the water, which covers the country during 

 several months of the year, and at such times they bi'eak up into 

 small family-parties of from half a dozen to a score of individuals, 

 something after the fashion of the Tsessobe, and then roam 

 through the bush country or wherever there is dry ground, while 

 large numbers doubtless migrate far to the east or south-east to 

 higher country. 



The calving season is regular, lasting from about the middle of 

 February to about the middle of March — that is to say, it takes 

 place just previous to the advent of the first rains, and in this 

 •assimilates closely to the habit of the Tsessobe. 



While in large herds in the open, Thiang are very wary and 

 will seldom allow aj)proach nearer than 250 yards ; probably at 



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