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Mammalian Biology

, Volume 71, Issue 6, pp 356–365 | Cite as

The burrow system of the African ice rat Otomys sloggetti robertsi

  • Andrea HinzeEmail author
  • Neville Pillay
  • Stefan Grab
Original investigation

Abstract

We studied the architecture of the burrow system of the African ice rat Otomys sloggetti robertsi, a non-hibernating, diurnal murid rodent endemic to the sub-alpine and alpine regions of the southern African Drakensberg and Maluti mountains. In our study site we found ice rat burrows in two substrates (organic and mineral soils). The structure of the burrow system was similar in both soil types, comprising several interlinking tunnels, numerous burrow entrances and 1–2 nest chambers. However, the surface area of the burrow systems in organic soils was larger, the tunnels were deeper, and some of the systems contained two levels, all of which was contrary to our assumption that digging would be more difficult in the compact organic soils. Ice rats occur in colonies of up to 17 individuals, and the collected efforts of several individuals are required for constructing complex burrow systems. The burrow structure is similar to those of two aridadapted relatives, Parotomys brantsii and Parotomys littledalei, suggesting that the burrow architecture among these three taxa may reflect the similar functions of burrows in extreme environments. For ice rats, burrows could provide a suitable microhabitat in which to escape adverse environmental conditions, particularly during winter. Moreover, ice rat burrows contained far fewer nest chambers than those of both Parotomys species, indicating that members in a. colony share nest chambers, thereby facilitating huddling. Finally, the extensive interlinking tunnels may provide underground routes to aboveground feeding sites, thereby reducing exposure to adverse conditions.

Key words

Otomys sloggetti robertsi burrow refuge nest alpine 

Die Baue der afrikanischen Eisratte Otomys sloggetti robertsi

Zusammenfassung

In dieser Studie untersuchen wir die Baue der afrikanischen Eisratte Otomys sloggetti robertsi, einem tagaktiven Nagetier, das in den alpinen und subalpinen Regionen der südlichen Drakensberge und Maluti Berge im südlichen Afrika endemisch ist, aber keinen Winterschlaf hält. In unserem Studiengebiet fanden wir Baue in zwei Substraten (organischem und Mineralboden). Die Struktur der Baue war in beiden Bodenarten ähnlich und enthielt einige Verbindungstunnel, zahlreiche Höhleneingänge und 1–2 Nesthöhlen. Die Baue im organischen Boden deckten allerdings eine größere Fläche ab und die Tunnel lagen tiefer als die Baue im Mineralboden. In manchen Bauen im organischen Boden fanden wir zwei übereinander liegende Stockwerke. Dies war im Gegensatz zu unseren Annahmen, dass das Graben im kompakten organischen Boden schwieriger sein würde und demnach die Komplexität der Höhlensysteme geringer wäre. Die Struktur der Baue der Eisratte ist denen von zwei arid-angepaßten Verwandten, Parotomys brantsii und P. littledalei ähnlich, was damit zusammenhängen könnte, dass die Baue aller drei Taxa dazu dienen, die Bewohner vor extremen Temperaturschwankungen zu schützen. Die Baue stellen Microhabitate dar, in denen die Eisratten nachteiligen Klimabedingungen entgehen können, vor allem im Winter. Allerdings haben die Baue der Eisratten viel weniger Nesthöhlen als die anderer Mitglieder der Unterfamilie Otomyinae, so dass sich die Koloniebewohner ein oder zwei Nester teilen müssen und daher wohl eng aneinander gedrängt schlafen. Die umfangreichen unterirdischen Tunnel ermöglichen den Eisratten Zugang zu verschiedenen Futterstellen, ohne dass sie längere Strecken in nachteiligen Klimaverhältnissen zurücklegen müssen.

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Copyright information

© Deutsche Gesellschaft für Säugetierkunde 2006

Authors and Affiliations

  1. 1.School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
  2. 2.School of Geography, Archaeology and Environmental StudiesUniversity of the WitwatersrandJohannesburgSouth Africa

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