ALLEN: MAMMALS FROM THE BLUE NILE VALLEY. 315 
well, and these were usually old bucks. One which Dr. Phillips shot, 
showed many battle scars about the neck from the horns of some 
others of its kind, by which it had probably been driven from the herd. 
Once I saw a young buck butting playfully at the rear of one in front, 
and on another occasion Dr. Phillips had a good opportunity to observe 
their manner of fighting. ‘Two bucks were seen fencing. They would 
lower their heads and catch each other’s horns by the hook-lke tips. 
Then followed a sort of tug-of-war in which one tried to pull the other 
about while their horns were thus interlocked. Sometimes they 
would butt at each other, and inflict sharp digs on the neck with the 
incurved tips of the horns. 
The chief food seemed to be grass, which was very closely grazed 
down on the ‘meres.’ Away from these places there was very little 
green vegetation except bushy growth, but everywhere the sprouting 
grass stalks were cropped off, and it was clear that green pasturage 
was none too plentiful for the big herds. The Ariel eat quantities of 
the date-shaped fruit of a species of thorn tree called the ‘laloab,’ 
which they pick up from the ground. This has a thin but juicy and 
rather acrid pulp with a large stone, enclosing a seed which is ground 
and eaten by the negroes. The stones appear to be regurgitated after 
the pulp has been digested, and it was common to find little heaps of 
half a dozen or so of these, quite cleaned, deposited on the ground. 
Our native hunters said that these were left by the Gazelles, after 
having been regurgitated, and though we did not actually see the 
process, there is no reason for doubting that this is the truth. 
These Gazelles seemed to be the most wary of the smaller antelopes. 
When feeding on the open with other grass-eating species, they were 
usually the first to take fright at our approach, and would move off, 
slowly at first, gathering sometimes into dense bunches like sheep, 
which they further simulated in their very whitish appearance. They 
are very conspicuous against the dark “cotton soil” or the burned 
areas, but among the dry and withered grass or on sand the contrast 
was less. They are constantly switching their tails from side to side, 
both when running or when standing, as though from sheer nervous- 
_ hess. I have seen the same habit in the Thompson’s and Grant’s 
gazelles. When surprised near the drinking places, they always 
_ Seemed much concerned to get back from the belt of tall grass or 
shrubbery near the bank of the stream, but on reaching the more open 
thorn scrub, would stop to look about. Evidently they feared lions 
or leopards lying in wait at such places. Lions certainly kill good 
numbers, and we found the remains of several recent “kills.” It was 
