Acanthocercus atricollis
The black-necked agama, Acanthocercus atricollis, is a species of tree agama found across East, Central, and southern Africa. These lizards are known for forming structured colonies and are often found in high densities near human settlements due to reduced predator presence. They are primarily insectivorous ambush predators.
Key Facts
- ›Native to East, Central, and southern Africa.
- ›Forms structured colonies with dominant males, females, and juveniles.
- ›Primarily an insectivore, with a diet including orthopterans, beetles, and ants.
- ›Often found in high densities near human habitation.
- ›Reproduction is seasonal, with females laying a single clutch of about 11 eggs per year.
- ›Males have larger heads than females, likely an adaptation for territorial competition.
Black-Necked Agama, Southern Tree Agama
Eritrea, Somalia, Ethiopia, Sudan, South Sudan, Uganda, D.R.C., Kenya, Tanzania, Zambia, Malawi, Mozambique, Zimbabwe, Angola, Botswana, Namibia, South Africa, Eswatini
Tree, Near Human Habitation, Secondary Growth
- Sexes Have Comparable Snout-To-Vent Length and Tail Lengths.
- Mature Males Have Somewhat Larger Heads Than Females.
- Females Reach Sexual Maturity At Approximately 96 mm Svl.
- Males Reach Sexual Maturity From About 82 mm Svl.
Orthopterans, Beetles, Ants, Millipedes, Various Arthropods
- Forms Structured Colonies With A Dominant Male.
- Males Defend Territories and Engage In Combat.
- Mostly Diurnal, But Sometimes Exhibits Nocturnal Activity.
- Adapts Readily To the Vicinity of Human Habitation.
- Ambush Foragers, Spending Little Time Moving.
- Stationary Adults Position Themselves On Lateral Branches, Tree Trunks, Or Occasionally the Ground.
Snakes, Raptors
About Acanthocercus atricollis
Acanthocercus atricollis: The Black-Necked Agama
The black-necked agama, scientifically known as Acanthocercus atricollis, is a species of tree agama native to a broad swathe of Africa, encompassing East, Central, and southern regions. It is particularly noted for its significant presence and high population densities in areas like the Kruger National Park in southeastern Africa.
Description and Habits
Adult males and females of Acanthocercus atricollis share comparable body lengths from snout to vent, as well as similar tail proportions. However, mature males tend to possess larger heads, a trait believed to be an evolutionary adaptation for engaging in territorial disputes. These lizards are social creatures, forming structured colonies that typically include a dominant male, several females, and juveniles. Males are territorial and will engage in combat to defend their areas. While primarily active during daylight hours, they are known to exhibit some nocturnal activity.
Acanthocercus atricollis is a master of camouflage and an ambush predator, spending a remarkably small percentage of its time in motion. When not hunting, adults position themselves on tree branches, tree trunks, or occasionally on the ground, blending into their surroundings. They have demonstrated a notable ability to adapt to environments near human settlements, frequently being found in higher densities around villages. This preference is often attributed to a reduction in natural predators, such as snakes and raptors, which are sometimes targeted by humans, and a liking for trees that offer denser foliage and canopy cover.
Diet and Reproduction
The diet of the black-necked agama is predominantly insectivorous, with a strong preference for orthopterans, beetles, and ants. Their digestive tracts have revealed a diverse consumption of arthropods, including a notable tendency to eat millipedes, a food source often avoided by other lizard species. Studies of gut contents show a significant proportion of ants, followed by orthopterans and beetles. Prey diversity and the volume consumed can fluctuate with the seasons. Reproduction is a seasonal affair for this species. Male testicular volume peaks in August and September, coinciding with the enlargement of female follicles from August to December. Females typically lay a single clutch of eggs per year, with an average of about 11 eggs. Larger females are capable of producing larger clutches, indicating a correlation between female size and reproductive output.
Source: Wikipedia ↗
Frequently Asked Questions
What is the scientific name for the black-necked agama?
The scientific name for the black-necked agama is Acanthocercus atricollis. This binomial nomenclature is used to classify this specific species within the animal kingdom.
Where is the Acanthocercus atricollis found geographically?
Acanthocercus atricollis has a wide distribution across East, Central, and southern Africa. Countries where it is found include Eritrea, Somalia, Ethiopia, Sudan, South Sudan, Uganda, D.R.C., Kenya, Tanzania, Zambia, Malawi, Mozambique, Zimbabwe, Angola, Botswana, Namibia, South Africa, and Eswatini.
What kind of habitat does the black-necked agama prefer?
Acanthocercus atricollis is a tree agama, often found in areas with trees that offer thicker canopies. They readily adapt to the vicinity of human habitation, particularly in villages where natural predators are less common.
What does the black-necked agama eat?
The black-necked agama is primarily an insectivore. Its diet consists mainly of orthopterans, beetles, and ants, but it also consumes other arthropods and is notable for eating millipedes, which many other lizard species avoid.
How does the black-necked agama reproduce?
Reproduction in Acanthocercus atricollis is seasonal. Females lay a single clutch per year, averaging about 11 eggs, with larger females typically producing larger clutches.
Are there any subspecies of Acanthocercus atricollis?
Two subspecies are generally accepted: Acanthocercus a. atricollis, found in southern Africa, and Acanthocercus a. loveridgei, found in Tanzania. While four more have been described, they are not considered very distinct.
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