Ceratogyrus

Ceratogyrus is a genus of African tarantulas in the family Theraphosidae, better known to keepers as the horned baboon spiders. They’re named for the distinctive foveal “horn” on the carapace that many, though not all, species develop, along with a characteristic pale sub-abdominal band. Today the genus contains 10 accepted species distributed across the drier savanna and scrub habitats of southern Africa, from Angola and Namibia through Botswana, Zimbabwe, Mozambique, Malawi and South Africa.

The genus was established in 1897 by British arachnologist Reginald Innes Pocock, based on a female Ceratogyrus darlingi collected near Chivhu in Zimbabwe, which remains the type species. In the same work he also described C. marshalli. The male of C. darlingi wasn’t formally described until Andrew M. Smith’s work in the 1980s, and early 20th-century arachnologists like Purcell, Hewitt and Hirst added several more species to the group.

Taxonomically, Ceratogyrus has had a bit of a roller-coaster. Purcell created a separate genus, Coelogenium, in 1902 for spiders with a strongly procurved fovea, but later revisions by De Wet & Dippenaar-Schoeman (1991) and especially Richard Gallon (2001) showed that Coelogenium and Ceratogyrus shared key features, leading Gallon to formally synonymise Coelogenium under Ceratogyrus and to transfer C. meridionalis into the genus from Pterinochilus. These revisions also cleaned up several misidentifications and synonymies, such as C. cornuatus being recognized as the female of C. marshalli and C. bechuanicus being sunk into C. darlingi.

Modern work has continued to refine the genus. Gallon described C. paulseni in 2005 from South Africa, and more recently Engelbrecht added C. attonitifer from Angola in 2019, bringing the group to its current 10 recognized species. Together they represent one of the most distinctive Old World baboon spider lineages—instantly recognisable in the hobby for that dramatic carapace horn and rugged, arid-adapted look.

Ceratogyrus marshalli

• Common name: Straight-Horned Baboon (Straight Horned Baboon Tarantula, Great Horned Baboon)

• Origin: Southeastern Africa – primarily Zimbabwe and Mozambique

• Lifestyle: Old World fossorial/obligate burrower; terrestrial heavy webber that spends most of its time in deep burrows

• Adult size: ~4–5" diagonal leg span

• Growth rate: Medium-to-fast to fast; males often mature in ~2–3 years, females in ~3–4 years with good husbandry

• Temperament: Very defensive and fast; best suited to experienced keepers; Old World species with potent, painful venom

• Color & appearance:

  • Earthy grey-brown body with lighter speckling and patterning on the abdomen

  • Iconic straight “unicorn-like” horn projecting from the carapace, the hallmark feature of this species

Species History

First described in 1897 by British arachnologist Reginald Innes Pocock, Ceratogyrus marshalli is one of the classic “horned baboon” tarantulas that helped define the genus Ceratogyrus in southern Africa. Originally collected in Zimbabwe, it quickly drew attention for the unusual straight horn rising from its carapace, a feature that has made it a favorite among horned baboon enthusiasts ever since. Over time it has become a well-established species in the hobby, with most specimens now produced through captive breeding rather than wild collection.

Natural Habitat

In the wild, the Straight-Horned Baboon is found in parts of Zimbabwe, Mozambique, and surrounding regions, where it lives in dry savanna and scrubland. Here it constructs deep vertical burrows in loose, sandy soil that buffer it from daytime heat and seasonal rains. The climate in much of its range is warm with distinct wet and dry periods, moderate annual rainfall, and relatively stable temperatures, making this species well adapted to semi-arid, open landscapes with scattered vegetation rather than dense forest.

Our Specimen:

Given name: Eba

Sex: Female

Life stage: Sub-adult

• A new addition to our collection, and very happy to have her.

• Took down two red roaches immediately after we housed her.

Ceratogyrus darlingi

• Common name: Rear-Horned Baboon Tarantula (also known as Burst Horned Baboon)

• Origin: Southern Africa – primarily Botswana, Zimbabwe, Mozambique, South Africa, and Lesotho

• Lifestyle: Old World, fossorial / obligate burrower that spends most of its time in deep, silk-lined burrows in arid savanna/grassland habitats

• Adult size: ~4.5–5 in (11–13 cm) diagonal leg span

• Growth rate: Fast growing; reaches near-adult size in just a few years

• Temperament: Very fast, defensive Old World species with strong venom; strictly a display animal and not recommended for handling or beginner keepers

• Color & appearance: Stocky baboon-type tarantula in ash-gray to mud-brown/black tones with lighter leg banding and mottled abdomen; features a distinctive backward-curving black “rear horn” on the carapace that makes the species instantly recognizable

Species History

Ceratogyrus darlingi (Pocock, 1897) is an Old World mygalomorph in the family Theraphosidae, subfamily Harpactirinae. It was originally described from material collected in southern Africa, with subsequent records expanding its known range across multiple countries in the region. Historically, several nominal species (e.g. C. bechuanicus) were described that are now regarded as junior synonyms, consolidating what was once a fragmented taxonomic picture into a single, widespread species.

As the type and best-known representative of the “horned baboon” complex, C. darlingi has been central to discussions of carapace morphology, fossorial adaptation, and intraspecific variation within Ceratogyrus. Its distinct posterior carapace protuberance (“horn”) and obligate burrowing behavior make it a key reference species for both taxonomic work and husbandry comparisons within Harpactirinae.

Natural Habitat

In situ, C. darlingi occurs in semi-arid to sub-humid regions of southern Africa, primarily within savanna and grassland biomes. These environments are characterized by pronounced wet–dry seasonality, well-drained sandy or sandy-loam soils, and relatively sparse tree cover with a continuous herbaceous layer.The species is strongly fossorial, constructing permanent, silk-reinforced burrows that may extend deep enough to buffer diurnal temperature and humidity fluctuations. Individuals typically occupy open or lightly vegetated microhabitats where soil structure permits stable burrow architecture. Nocturnal emergence is primarily for ambush predation on ground-dwelling invertebrates, with the burrow serving as both a refuge from predators and a critical microclimatic refuge during seasonal extremes.

Our Specimen:

Given name: Man

Sex: TBD

Life stage: Sub-adult

• Our specimen enjoys digging and burrowing, which is typical for this species.

• Typically an excellent eater.

Ceratogyrus sanderi

• Common name: Sandy Horned Baboon / Namibian Horned Baboon Tarantula

• Origin: Southern Africa, primarily Namibia, with records from nearby regions in southwestern Africa

• Lifestyle:

  • Terrestrial, fossorial baboon species

  • Digs and lives in deep burrows in firm, sandy or savannah soils

  • Adapted to arid to semi-arid scrub/savannah; prefers dry conditions in captivity

• Adult size:

  • Body length around 4–5 cm (1.5–2")

  • Leg span roughly 12–14 cm (4.5–5.5")

• Growth rate:

  • Fast-growing for an Old World terrestrial

  • Slings and juveniles gain size quickly with warm temps and regular feeding

• Temperament:

  • Defensive to aggressive, classic Old World baboon behavior

  • Very fast, reactive, and prone to standing its ground

  • Best suited to experienced keepers

• Color & appearance:

  • Stocky tarantula with the genus’ trademark carapace “horn” (in this species usually a lower, rounded horn)

  • Overall sandy to golden-brown coloration with darker mottling and a desert-camouflage look

  • Legs are dusky brown to grey-brown, giving a compact, heavily built horned baboon appearance

Species History

Ceratogyrus sanderi, commonly called the Namibian or Sandy Horned Baboon, is an Old World tarantula in the African subfamily Harpactirinae. It was described in the early 1900s by arachnologist Embrik Strand from specimens collected around Windhoek, Namibia, and later records extended its known range into other parts of southern Africa.

The species belongs to the genus Ceratogyrus, a group of “horned baboon” tarantulas named for the raised horn-like structure on the carapace. For many years C. sanderi was overshadowed in the hobby by more widely traded relatives such as C. darlingi and C. marshalli, but increased captive breeding has made it more available. Today it’s valued among experienced keepers for its hardy nature, sandy coloration and distinctive but relatively subtle horn.

Natural Habitat

In nature, C. sanderi occurs in the dry regions of southern Africa, especially Namibia, with populations also reported from nearby countries such as Angola, Botswana and Zimbabwe. It inhabits arid to semi-arid savannas, open scrubland and grassland where summers are hot, nights can be cool, and rainfall comes in short, seasonal bursts rather than year-round.

This is a fossorial species that digs deep burrows in firm, sandy or sandy-clay soils. The burrow provides a stable, slightly more humid microclimate and protection from predators and extreme surface temperatures. These natural conditions translate in captivity to a preference for deep, mostly dry substrate, good ventilation, and a simple layout that allows the spider to construct and maintain a secure burrow.

Our Specimen:

Given name: TBD

Sex: TBD

Life stage: Sling

• A new addition to our collection