APPENDIX C 485 



traps one afternoon I 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 (Aruicanthus pumilio minulus). 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 Hall 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 vegetation had been burned were innumer- 

 able holes where some animal had dug about the base of grass tufts. Their 

 signs did not extend further 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-colored 

 mole rat took this animal's 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 further be- 

 yond. 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 rex). 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 



