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Rhynchocyon

Genus of mammals

  • 12 min read
  • 4 chapters

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  • Golden-rumped sengi, Rhynchocyon chrysopygus
    • Rhynchocyon chrysopygus mandelai
  • Chequered sengi, Rhynchocyon cirnei
    • Rhynchocyon cirnei shirensis
    • Rhynchocyon cirnei reichardi
    • Rhynchocyon cirnei hendersoni
    • Rhynchocyon cirnei macrurus
  • Black and rufous sengi, Rhynchocyon petersi
    • Rhynchocyon petersi adersi
  • Stuhlmann's sengi, Rhynchocyon stuhlmanni
  • Grey-faced sengi, Rhynchocyon udzungwensis

Biology and ecology

The giant sengis are endemic to Africa, and usually live in lowland montane and dense forests, often "avoiding" edges of forest patches. These dense forests play a role in their shelter and reproduction, as they provide the ecological niche in which sengis exploit. They are typically active in the day (diurnal), spending their nights hidden in the shelters that they build the morning prior. After a few nights of use, sengis tend to abandon their shelters to create new ones elsewhere. They typically build their shelters at ground level, requiring dry leaf litter. The primary structure of a nest for R. udzungwensis, for example, consists of the excavation of a cup-like indentation in the soil, layered with leaves, and then covered with looser leaves as a roof covering. They usually construct their nests at the base of trees. They also use hollowed, fallen trees or trunks to retreat in shelter, especially when faced with predation. Sengis respond to disturbances by staying still or making loud thumping noises on the forest floor. In instances of predation, the giant sengi uses a half-bound gait to rapidly run away.

Other Macroscelidea species are known to bask in the sun, as a method of thermoregulation to save energy. Giant sengis do not bask—and it is most likely due to their adaptation to shaded canopy forest environments.

Sengis live in monogamous pairs, defending hectare-sized territories. Pairs spend little time together except when the female is in estrous. Mating occurs quickly and offspring grow quickly with minimal parental investment—none of which is paternal.

It has been observed that the genus has a commensal relationship with a variety of ground-foraging birds throughout its ranges. Both the Red-capped robin-chat and White-chested alethe often follow the giant sengis as they forage, in attempt at capturing prey that is disturbed while they shuffle through leaf litter looking for prey. They eat primarily insects such as beetles, termites, ants, and centipedes, using their proboscises to dig them from the soil and its tongue to lick them up. Their facial morphology limits their diets to tiny invertebrates, and unlike other members of Macroscelidea, do not supplement their diet with foods such as nuts or small fruits.

Identification

Each species exhibits distinct and varying coat patterns and colors. Species and subspecies found in denser forests exhibit darker coloration and patterns while open woodland species exhibit lighter, chequers. The darker species R. petersi, R. chrysopygus, and R. udzungwensis still contain vestigial chequers, but are masked by the blended dark fur between them. This makes coat patterns an unreliable indicator of species delineation though useful for identification. The species are described as follows:

  • R. chrysopygus exhibits a bright yellow patch of fur on its rump with very little black coloration at all. R. chrysopygus has a unique dermal shield (a specialized thickening of skin) on its rump.
  • R. petersi has mostly orange-rufous coloration on its feet, ears, tail, chest, and on its face. Black fur extends from its rump and thighs up to its shoulders. Subspecies R. p. adersi has the same pelage.
  • R. udzungwensis has black feet, ears and a tail. Its face is griseous grey with its lower rump and thighs are black. The chest is pale yellow.
  • R. cirnei and its subspecies feature six dark-colored stripes and spots (chequers) on its back. They contain little to no black fur, are lighter in color, and differ markedly by their lack of orange-rufous coloration found on its coastal relatives R. petersi, R. chrysopygus, and R. udzungwensis. The subspecies R. c. macrurus exhibits a clinal variation different from coastal populations towards inland populations (being darker on the coast and lighter inland).
  • R. stuhlmanni exhibits a similar coloration and pattern as R. cirnei differing notably by its white tail. Populations get darker to the east and lighter to the west in a cline.

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Monotypic taxonTaxonomic group with only one subordinate taxonSpecies descriptionFormal description of a discovered speciesParaphylyType of taxonomic groupIUCN Red ListInventory of the global conservation status of biological speciesSubtropicsGeographic and climate zoneCommon nameName generally used for a taxon, group of taxa or organism(s)