Geogale has traditionally been placed in the monotypic subfamily Geogalinae. An African origin of tenrecs is widely accepted. Some authorities suggest that Geogale and the other tenrecs of Madagascar share a common ancestor, and have diverged from one another after a single colonization of the island. However, there is some evidence that Geogale may not have arizen from the same colonization event that links the other tenrecs of Madagascar.
Currently G. aurita is considered the sistergroup of the remaining tenrecs, and it is the only living descendent along its branch; the remaining Malagasy species are descendents of the other branch.
Due to dental similarities to Geogale in a fossil found in Miocene deposits of Kenya, this fossil was originally placed in Geogale. These dental similarities were considered too specialized to give rise to the remaining tenrecs, thus the ancestor of Geogale must have had colonized Madagascar independently.
The identification of this fossil has since been disputed, and is now taxonomically placed as Parageogale. The phylogenetic relationship to other members of the family Tenrecidae remains uncertain, but molecular and morphological evidence suggests a sister relationship, thus supporting a two colonizations hypothesis.
Large-eared tenrecs use sound to locate their termite prey. Being a nocturnal animal with poor eyesight, G. aurita depends on auditory and olfactory senses. As in all mammals, tactile communication is important between mates as well as between mothers and their offspring. Accoustic communication between members of this species has not been reported, but may occur.
Communication Channels: tactile ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Large-eared tenrecs do not appear to be threatened, but as they are dependent on forest habitats, their distribution may decrease with increasing loss of suitable habitats. Other threats are indirect effects due to increased use of pesticides. Geogale aurita is a specialized termite feeder and termites are affected by pesticides. Thus, the potential effect on G. aurita appears high.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Large-eared tenrecs have no known specific economic influence on human societies.
Habitats populated by large-eared tenrecs are not densely populated by humans, thus no known specific economic influence on human societies is known.
Large-eared tenrecs are specialized termites feeders and thus act as secondary consumers in an ecosystem. The species also provides feeding opportunities for consumers at higher trophic levels.
Large-eared tenrecs are specialized insectivores showing a clear preference for termites. Their diet consists exclusively of arthropods, which they locate by using sound. They may also show a significant preference for certain species.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
Large-eared tenrecs are endemic to the island of Madagascar and are found in the south and southwest regions of the island.
Biogeographic Regions: ethiopian (Native )
Other Geographic Terms: island endemic
Geogale aurita is found widely distributed in dry, deciduous forest, gallery forests, and spiny bush in southern and southwestern Madagascar. The species has also been observed in the rainforest of the southeast. These are environments with large annual variations in rainfall.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest ; scrub forest
The lifespan of long-eared tenrecs living in the wild is unknown but in captivity they have been observed to live for more than two and a half years.
Range lifespan
Status: captivity: more than two and a half (high) years.
Typical lifespan
Status: captivity: 2.5 (high) years.
Large-eared tenrecs are small, shrew-like tenrecs with very short, soft pelage, hair-covered tails, and large pinnae. Dorsal coloration is variable, ranging from light gray to light reddish-brown. Ventrally, these animals are buffy white. Large-eared tenrecs are among the smallest living tenrecs, with wild-caught animals ranging in body mass from 5.0 to 8.5 g. The length of the head and body is 60 to 75 mm, and the total body length including the tail can be between 90 and 105 mm.
Certain characters distinguish G. aurita from other tenrecs. The dental formula is 2/2 1/1 3/2 3/3 = 34, whereas most tenrecs have 36 teeth. Furthermore, large-eared tenrecs are the only member of the family Tenrecidae that exibit postpartum oestrus, which allows females to suckle a first litter while a second litter is developing in utero.
Geogale aurita is heterothermic, and body temperatures parallel the surrounding temperature at all times of year, although body temperatures higher than ambient temperature are observed in pregnant and lactating females. Low metabolic rate is correlated with this relatively low body temperature.
Testes are abdominal in G. aurita, as they are in all other tenrecs. Members of the family Tenrecidae have a cloaca into which both the intestinal and genitourinary tracts empty.
Range mass: 5.0 to 8.5 g.
Average mass: 6.0 g.
Range length: 90 to 105 mm.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Average basal metabolic rate: 0.043 W.
Geogale aurita is preyed upon by various groups of animals. Remains of large-eared tenrecs have been found in pellets from two species of owls: barn owls and Madagascar long-eared owls. Other species expected to be predators of large-eared tenrecs are snakes, including Malagasy cat-eye snakes, which are associated with the habitat where Geogale is found, and carnivores such as Malagasy narrow-striped mongooses.
Known Predators:
Information on the mating systems of these tenrecs was not available in the literature reviewed. Mating systems of tenrecs in general are poorly known. Most tenrecs are solitary, although some species appear to form stable long-term bonds between males and females, indicating that they may mate monogamously. It is not known at this time what mating system is employed by G. aurita.
Mating takes place from late September to March. Because these animals have a post-partum estrus, they can produce multiple litters during that time. Coital lock occurs during copulation and can last for more than 20 minutes. Large-eared tenrecs are capable of arresting the development of litters, thus the gestation period varies between 54 and 69 days. Litter size varies from 1 to 5 individuals, and the weights of the neonates range from 0.5 to 0.8 g. The offspring are altricial, and are born with closed eyes and ears. Young are weaned soon after the opening of eyes, which takes place after 21 to 33 days of age.
Breeding interval: It is not known how often these animals breed in the wild.
Breeding season: Breeding occurs in late September to March.
Range number of offspring: 1 to 5.
Range gestation period: 54 to 69 days.
Range weaning age: 21 to 33 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; embryonic diapause ; post-partum estrous
Average birth mass: 0.7 g.
Average number of offspring: 3.9.
Parental care in this species has not been described. However, because G. aurita is a mammal, we know that females provide extensive maternal care. Young are altricial, so it is likely that mothers provide not just food to their young, but also protection, grooming, and shelter, until the time that the young are weaned and can care for themselves. Male parental care is varied in mammals, and lacking specific information for these tenrecs, it is impossible to speculate upon.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
The large-eared tenrec (Geogale aurita) is a species of mammal in the family Tenrecidae. It is the only species in the monotypic genus Geogale, and the only member of the subfamily Geogalinae.[1] It is endemic to Madagascar where its natural habitats are subtropical or tropical dry forests and shrubland. It is threatened by habitat loss, but to a lesser extent than was previously thought and is listed by the IUCN as being of "Least Concern".
Geogale is thought to have split from the ancestors of its sister clade, the subfamily Oryzorictinae, about 30 million years ago.[3]
The large-eared tenrec is a small shrew-like animal with short, soft fur, a long hairy tail and large projecting ears. Adults weigh between 5 and 8 grams (0.18 and 0.28 oz) and measure 60 to 75 millimetres (2.4 to 3.0 in) in length, with a tail half as long again. The dorsal (upper) surface is greyish brown or reddish brown and the ventral (under) surface is buffish white.[4] The large-eared tenrec differs from other tenrecs in the family by having 34 teeth instead of 36. It is also unique within the family in that females come into oestrus while they are lactating and so are able to be carrying one litter while still feeding another.[4]
The large-eared tenrec feeds on insects, particularly termites which it locates by sound. It is itself preyed on by several predators including the barn owl (Tyto alba), the Madagascar owl (Asio madagascariensis), the Malagasy cat-eye snake (Madagascarophis colubrinus) and the narrow-striped mongoose (Mungotictis decemlineata).[4]
The large-eared tenrec has a low metabolic rate and is heterothermic. This means that its body temperature fluctuates with the surrounding environment, although pregnant and lactating females may maintain a more steady, higher temperature.[4] The animals are often torpid in the heat of the day, hiding in concealed locations such as hollow logs or holes.[4] Reproduction has been little studied in this species, but the breeding season is between September and March. It is known that development can be arrested temporarily and the gestation period may vary between about 54 and 69 days. A litter consists of up to five blind, deaf and helpless young and these are weaned when between 21 and 33 days old, soon after their eyes have opened.[4]
The large-eared tenrec is listed by the IUCN in its Red List of Threatened Species as being of "Least Concern". The population trend is unknown and although this tenrec has been recorded in various scattered areas of Madagascar, it is a small, inconspicuous animal and is likely to also be present in intervening locations. It had been thought to be restricted to dry deciduous forest but it has now also been found in grassland and is probably more resilient to disturbed habitat than had previously been realised. Some of the areas in which it occurs are in national parks and nature reserves.[2]
The large-eared tenrec (Geogale aurita) is a species of mammal in the family Tenrecidae. It is the only species in the monotypic genus Geogale, and the only member of the subfamily Geogalinae. It is endemic to Madagascar where its natural habitats are subtropical or tropical dry forests and shrubland. It is threatened by habitat loss, but to a lesser extent than was previously thought and is listed by the IUCN as being of "Least Concern".
Geogale is thought to have split from the ancestors of its sister clade, the subfamily Oryzorictinae, about 30 million years ago.
