496 
APPENDIX C 
and leaves were found. While setting traps one afternoon 1 saw what 
might have been one of these rats dart from a deserted bird’s-nest and 
run down a limb to the ground. The following morning I caught a 
masked tree rat in a trap set beneath the nest. 
Four-striped Grass Rat ( Arvicanthus pumilio minutus ). At Naivasha we first 
came across this species, where it was found on the east side of the lake 
only, although the spotted rat was common on both the east and the 
west side. At Naivasha these two animals inhabited slightly different 
regions. In the brushy and grassy thickets bordering the lake spotted 
rats were abundant, but a few four-striped rats were captured. As soon 
as the traps were transferred to thorn-tree groves, where there was 
plenty of under-bushes, and not so much grass and weeds, the spotted 
rats were found in great numbers, but no four-striped rats. All the way 
from Fort Hail to Mount Kenia, and as high as 10,700 feet, where 
Dr. Mearns secured one specimen, this species was common. We also 
caught them along the route between Kampala and Butiaba. 
Giant Rat ( Thrynomys gregorianus). Along the skirtings of the rivers in the 
thick weeds, grass, and bushes at Fort Hall signs of these animals were 
common. There were no well-defined paths. Footprints the size and 
shape of those made by our muskrats {Fiber) were found in the mud at 
the water’s edge, and here and there were clusters of grass and weed- 
stems cut in lengths averaging six inches. In sections where the vegeta¬ 
tion had been burned were innumerable holes, where some animal had 
dug about the base of grass-tufts. Their signs did not extend farther 
than fifty feet from water. While passing through a thicket close to the 
water, I started a large rodent, which darted through the grass and 
plunged into the water. 
Mole-Rat {Tachyoryctes splendens ibeanus ). Mounds of earth that these rats 
had thrown from the mouth of their burrows at the time that the tunnels 
were made were found as far west as Oljoro O’Nyon River, but none at 
N’garri Narok River. At our camp on the South Guaso Nyero River a 
pale, mole-coloured mole rat took this animaFs place. Some fifteen miles 
west of Lake Naivasha mole-rats became common, and on the sandy flats, 
within five miles of the lake, they were so abundant that our horses 
broke into their runways nearly every step. Their underground tunnels 
and the mounds of earth that were thrown out were similar to those 
made by the pocket gophers of Western United States. Many were 
snared by the porters and brought to camp alive. They would crawl 
about slowly, not attempting to run away, but looking for a hole to enter. 
After the lapse of a few seconds they would begin to dig. In any slight 
depression they began work ; and when small roots or a tussock of grass 
intervened, they used their teeth until the obstruction was removed, and 
then, with the nails of their front feet only, continued digging. As the 
hole deepened they threw the dirt out between their hind-legs, and with 
them still farther beyond. After the earth had accumulated so that it 
drifted back, they faced about, and, using their chest as a scoop, pushed 
it entirely out of the way. They were most active in the evening, at 
night, and in early morning. Several were found dead near their holes, 
having evidently been killed by owls or small carnivorous mammals. 
Alpine Mole-Rat {Tachyoryctes re,v). Mole-rat mounds were common about 
the West Kenia Forest Station, but none were seen between 7,500 and 
8,500 feet, and from this altitude they ranged to 11,000 feet. They 
inhabited all of the open grassy plots in the bamboo belt and in the open 
timber. The “ boys ” snared many in nooses ingeniously placed in the 
runs that were opened and closed after the trap was set. While digging 
into the burrows, several times I found bulky nests of dried grass in side 
