Overview

Mops ansorgei – (Thomas, 1913)

ANIMALIA – CHORDATA – MAMMALIA – CHIROPTERA – MOLOSSIDAE – Mops – ansorgei 

Common Names: Ansorge’s Free-tailed Bat, Ansorge’s Wrinkle-lipped Bat (English), Ansorge se Losstertvlermuis, Ansorge–osstertvlermuis (Afrikaans), Ansorge-Bulldoggfledermaus (German), Molosse d’Afrique du Sud, Molosse d’Ansorge, Tadaride d’Ansorge (French)
Synonyms: Nyctinomus ansorgei Thomas, 1913; Chaerephon ansorgei (Thomas, 1913); Chaerephon rhodesiae Roberts, 1946; Tadarida ansorgei (Thomas, 1913) 

Taxonomic Note: 
This species was previously listed under Tadarida (Hayman & Hill 1971; Largen et al. 1974; Corbet & Hill 1980), and is physically very similar to Tadarida aegyptiaca, especially in pelage colour, although somewhat smaller in size. However, Koopman (1975) and Freeman (1981) described the relationship between this species and Chaerephon bivitatta and C. bemmeleni, and resultantly included this species under the genus Chaerephon, which was later supported by Meester et al. (1986) and Koopman (1993). Lamb et al. (2011) found strong support for the monophyly of the Chaerephon and Mops taxa (about 17.2 Mya), but not for either of the genera separated. Ammerman et al. (2012) also found support for a Mops – Chaerephon clade, which resulted in paraphyly of Chaerephon, and confirm again that Chaerephon is distinct from Tadarida. A further morphological study by Gregorin and Cirranello (2015) confirmed the paraphyly of Chaerephon but was unable to resolve the relationships with the genus. Simmons and Cirranello (2020) include all the Chaerephon species in the genus Mops. No subspecies have been identified. 

Red List Status: LC – Least Concern (IUCN version 3.1) 

Assessment Information

Assessors: Naidoo, T.¹, Richards, L.R.¹, Balona, J.² & da Silva, J.M.³ 

Reviewers: Richardson, E.J.⁴ 

Institutions: ¹Durban Natural Science Museum, ²Gauteng and Northern Regions Bat Interest Group, ³South African National Biodiversity Institute ⁴Independent Consultant at Richardson & Peplow Environmental 

Previous Assessors and Reviewers: Monadjem, A., Taylor, P., Cohen, L., Jacobs, D., MacEwan, K., Richards, L.R., Schoeman, C. & Sethusa, T. 

Previous Contributors: Roxburgh, L., Raimondo, D. & Relton, C. 

Assessment Rationale 

The species is widely but sparsely distributed across the northeastern regions of the assessment region and has been recorded predominantly from protected areas. The estimated extent of occurrence is 106,515 km². It occurs in hard-to-reach places and is difficult to sample owing to its fast, high-flying habits, but the population is suspected to be stable. There are no known major threats to the species, and it is thus listed as Least Concern.

Regional population effects: This species has been commonly recorded in Zimbabwe and genetic exchange between individuals occurring within and outside of the assessment region is suspected. 

Reasons for Change 

Reason(s) for Change in Red List Category from the Previous Assessment: No change 

Red List Index 

Red List Index: No change

Recommended citation: Naidoo T, Richards LR, Balona J & da Silva JM. 2025. A conservation assessment of Mops ansorgei. In Patel T, Smith C, Roxburgh L, da Silva JM & Raimondo D, editors. The Red List of Mammals of South Africa, Eswatini and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Regional Distribution and occurrence

Geographic Range 

Mops ansorgei occurs across much of eastern sub-Saharan Africa through to the Kruger National Park and northern KwaZulu-Natal (ACR 2024), with the core of its range being Zimbabwe (Monadjem et al. 2020). It has not been recorded from Botswana. A possible geographically isolated population is restricted to western Angola (Monadjem et al. 2020). A habitat model suggests that suitable conditions occur in southern Mozambique (Monadjem et al. 2020). Within the assessment region it is found sparsely in the Limpopo, Mpumalanga, and KwaZulu-Natal provinces, recorded mostly from protected areas. 

Elevation / Depth / Depth Zones 

Elevation Lower Limit (in metres above sea level): 400 

Elevation Upper Limit (in metres above sea level): 2000 

Depth Lower Limit (in metres below sea level): (Not specified) 

Depth Upper Limit (in metres below sea level): (Not specified) 

Depth Zone: (Not specified) 

Figure 1. Distribution records for Ansorge’s Free-tailed Bat (Mops ansorgei) within the assessment region (South Africa, Eswatini and Lesotho). Note that distribution data is obtained from multiple sources and records have not all been individually verified.

Biogeographic Realms 

Biogeographic Realm: Afrotropical 

Occurrence 

Countries of Occurrence 

Large Marine Ecosystems (LME) Occurrence 

Large Marine Ecosystems: (Not specified) 

FAO Area Occurrence 

FAO Marine Areas: (Not specified) 

Climate change

Studies of bat species have shown that environmental suitability is associated with temperature, precipitation, topographic variables, vegetation cover and waterway presence (Koch et al. 2020, Lee et al. 2012 and Uusitalo et al. 2024). However, the specific effects of climate change have not been documented for this species. Mops ansorgei is associated with savanna woodland habitats of the extreme eastern, and northeastern regions of South Africa. It is therefore likely that increased drought frequency in some of the semi-arid savannas may impact the vegetation and insect prey base of this species (likely to be moths as is the case for similar-sized large molossids) (Goana et al. 2024).  This is turn may result in distributional changes and altered roosting patterns.  

Population Information

In the assessment region this species is suspected to be uncommon as it is difficult to capture, and most records appear to be isolated (Skinner and Chimimba 2005). However, colonies outside of the assessment region have been recorded as consisting of hundreds of individuals (Mickleburgh et al. 2008). This species is well represented in museums from within the core of its range in Zimbabwe, where more than 250 individuals were examined in Monadjem et al. (2020). 

Current population trend: Stable 

Continuing decline in mature individuals? Not determined, but unlikely 

Extreme fluctuations in the number of subpopulations: Not known 

Continuing decline in number of subpopulations: Not known 

All individuals in one subpopulation: Suspected, based on ecomorphology and dispersal capability 

Number of mature individuals in largest subpopulation: Not determined, but can roost in large colonies elsewhere in Africa 

Number of Subpopulations: One, comprised of different colonies 

Quantitative Analysis 

Probability of extinction in the wild within 3 generations or 10 years, whichever is longer, maximum 100 years: Not known, but unlikely) 

Probability of extinction in the wild within 5 generations or 20 years, whichever is longer, maximum 100 years: Not known 

Probability of extinction in the wild within 100 years: Not known 

Population Genetics

No population-level genetic study has been conducted on this species; however, dispersal capability is thought to be high based on the species’ high wing loading as is seen with other similar-sized molossids (Taylor et al. 2012). Consequently, it is expected to exist as a metapopulation, possibly well connected to populations in neighbouring countries. Due to limited information on the overall population size within the assessment region. it is not possible to estimate effective population size (Ne) using proxy methods. A population genetic study incorporating samples within and outside of the assessment region would be highly informative in understanding the genetic health of this species.  

Habitats and ecology

This species inhabits dry woodland savannah habitats, usually near to rugged hills and mountains with rocky cliffs (Monadjem et al. 2020). Natural roost sites include narrow cracks in rocks, especially on cliff faces (Cotterill and Fergusson 1993), but is known to roost in buildings, roofs of houses, mine adits and expansion joints of bridges (Cotterill, 2013; Monadjem et al. 2020). The availability of natural roost sites is considered a primary habitat requirement for this species (Skinner and Chimimba 2005). Coleoptera, Trichoptera and Lepidoptera constitute most of this species’ diet (Fenton 1985). It is a gregarious species and roosts communally, usually in small to medium-sized groups (Allen et al. 1917). In Zimbabwe, reproductive studies have shown that it generally produces a single young in late November, with a second birth peak occurring in April (at the end of the warm, wet season) (Monadjem et al. 2020).

Ecosystem and cultural services: As this species is an aerial insectivore, it may contribute to controlling insect populations that destroy crops (Boyles et al. 2011, Kunz et al. 2011).  Ensuring a healthy population of insectivorous bats can thus result in a decrease in pesticide use. 

IUCN Habitats Classification Scheme 

Life History 

Generation Length: Suspected to be 1-3 years 

Age at Maturity: Female or unspecified: Approximately 1 year based on available data for other molossid species 

Age at Maturity: Male: Approximately 1 year based on available data of other molossid species 

Size at Maturity (in cms): Female: Mean total length = 10.60 ±0.61 cm; Mean forearm length = 4.60 ±0.15 cm (Monadjem et al. 2020) 

Size at Maturity (in cms): Male: Mean total length = 11.60 ±0.73 cm; Mean forearm length = 4.72 ±0.28 cm (Monadjem et al. 2020) 

Longevity: Not known 

Average Reproductive Age: Approximately 1 year based on available data of other molossids 

Maximum Size (in cms): Not known 

Size at Birth (in cms): Not known 

Gestation Time: Presumed to be approximately 3 months  

Reproductive Periodicity: Seasonal polyoestry with young born in the austral summer and mid-autumn (Cotterill 2013) 

Average Annual Fecundity or Litter Size: Presumed to be 1 pup 

Natural Mortality: Preyed upon by Barn owls (Tyto alba) and Eagle-owls (Bubo capensis) (Cotterill 1992) 

Breeding Strategy 

Does the species lay eggs? No

Does the species give birth to live young? Yes

Does the species exhibit parthenogenesis? No

Does the species have a free-living larval stage? No

Does the species require water for breeding? No

Movement Patterns 

Movement Patterns: Unknown 

Congregatory: Yes, in other parts of Africa 

Systems 

System: Terrestrial 

General Use and Trade Information

There is no evidence to suggest that this species is traded or harvested within the assessment region. However, in some parts of West Africa it is utilised (and possibly even over-utilised) as bushmeat (Mickleburgh et al. 2008). 

National Commercial Value: No 

International Commercial Value: No 

Is there harvest from captive/cultivated sources of this species? No 

Harvest Trend Comments: N/A 

Threats

No major threats have been identified for this species within the assessment region, although minor threats such as human disturbance at roost sites and the climatic impacts associated with global climate change have been identified for other bat species and may similarly impact this species. In parts of West Africa this species may be vulnerable to overexploitation as a food source (Mickleburgh et al. 2008). There are also historic records from northeastern Democratic Republic of Congo of people suffocating bucket-loads of Ansorge’s Free-tailed Bats to death in their roosting sites (Allen et al. 1917). 

With wind energy installations moving into parts of KwaZulu-Natal and Mpumalanga, this could pose a future threat to Ansorge’s Free-tailed Bat as it is an open-air forager (Baerwald et al. 2008, Cryan and Barclay 2009, Rydell et al. 2010, Rollins et al. 2012), and is categorised as high risk for turbine related fatalities (MacEwan et al. 2020). Bats are attracted to wind farm sites which often tend to have higher insect densities at well-lit turbines (Voigh et al. 2024). When bats fly near to turbine blades, they either collide directly with the blade or they experience barotrauma. Barotrauma is tissue damage caused by rapid excessive changes in air pressure near turbine blades (Baerwald et al. 2008, Rydell et al. 2010). Additionally, this species may face persecution when roosting in the roofs and crevices of buildings, even in protected areas. 

Conservation

Within the assessment region, this species has been found in the Kruger National Park, Mapungubwe National Park, Vhembe Biosphere Reserve, and  Mkhuze Game Reserve in KwaZulu-Natal. No specific conservation efforts are necessary at present, although they are likely to benefit from enhanced protection of key roost sites and awareness of the species ecological value in controlling insect populations.

Recommendations for land managers and practitioners: 

•  Reduce pesticide use in agricultural landscapes. 

Research priorities: 

• Field surveys are needed to identify further subpopulations and delimit its distribution range more accurately. 

• The reproductive and feeding ecology of Ansorge’s Free-tailed Bat requires further investigation. 

Encouraged citizen actions: 

• Citizens can assist the conservation of the species by reporting sightings on virtual museum platforms (e.g., iNaturalist and MammalMAP) and therefore contribute to an understanding of the species distribution. Ansorge’s Free-tailed Bat closely resembles the Egyptian Free-tailed Bat (Tadarida aegyptiaca) but is slightly smaller in size and lacks the unusually flattened skull seen in T. aegyptiaca (Rautenbach 1997). 

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