The ecology and behaviour of naked mole-rats were studied for two years in Tsavo National Park (West) in Kenya, backed up by captive work on these blind colonial bathyergid rodents. 14 colonies captured contained 70-80 animals on average. In each colony. only a single breeding female reproduced, producing litters of 5-13 young year-round. Analysis of capture data and a mark-recapture programme provided evidence for a tendency towards defensive behaviour by large animals and worker behaviour by small animals. The production of mole-hills was found to be strongly associated with seasonal rainfall. One colony produced 400-500 mole-hills per year, equivalent to 3.6-4.5 tonnes of soil or 2.3-2.9 kilometres of new burrows. The digging efficiency of individuals and cooperative teams of mole-rats was found to be limited by extremely hard. dry soils, and reduced in saturated soils. 20 individuals from one colony were radio-tracked. The complete burrow system was found to be exceedingly complex and over 3 kilometres in length. Individual activity and foraging behaviour were inversely related to size. Activity levels were closely correlated with surface burrow temperatures. Most mole-rat food consisted of large. randomly distributed tubers found deep down, and small tubers in dense. well-defined and widely dispersed patches near the surface. Radio-tagged animals apparently burrowed for the large tubers and patches at random. but used area restricted searching within patches of small tubers. Predation by snakes in surface burrow networks was observed. and anti-predator behaviour of mole-rats recorded. It was concluded that Heterocephalus colonies are limited by the distribution and biomass of food resources, and the energetic and tooth-wear costs of locating them: this requires group-living. Inbreeding and kin selection in isolated groups contribute to the development of eusociality in Heterocephalus.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:543077 |
| Date | January 1986 |
| Creators | Brett, Robert Alan |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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