Red-headed Agama

Order:    Squamata                                                                                 Family: Agamidae                                               

Scientific name: Agama agama                                                           U.S. common name: Red-headed agama

Other names: Common agama

Geographic range currently: Senegal east to Ethiopia, and south to northern Angola and southern Tanzania

Habitat: Rocky outcroppings, cliffs, savannahs, farms, houses, and villages

Circadian cycle: Diurnal

 

Size

 

General range                       male                                       female                                                    hatch

 

Head & tail length:                                  200-250 mm                    250 mm                                  200 mm                                                   112-113 mm mm                                                                   

Sexual dimorphism: Males are slightly larger than females and the dominant male has a red head and tail, blue body and limbs during the day. At night the

                                    females, subordinate males, and dominant males are brownish. 

 

Reproduction

 

Mating Season: During the wet season although they are capable of reproducing year-round in areas with consistent rainfall.

Gestation period: 8-10 weeks

Courtship: The male will approach the female from behind and head bob to her. If she accepts then she will arch her back with her tail and head raised.

Copulation: The male walks to her side and grasps her neck and puts his leg on the female's back, the pair swivel 90 degrees in order to bring their cloacas

                      together and thrusts his tail onto her cloaca inserting his right or left hemipenes (depending on side location). This mating ritual usually lasts one

                      to two minutes when the female will scurry away and the male also after several minutes.

Sexual maturity: Females reach sexual maturity at age fourteen to eighteen months, males at two years.

Other information: The female lays her eggs in a hole she digs with her snout and claws. The hole is five centimeters deep and is found in sandy, wet, damp

                                    soil that is exposed to sunlight nearly all day and covered by herbage or grasses. The eggs are usually laid in clutches ranging from five

                                    to seven ellipsoidal eggs. A. agama is a thermoregulated embryo species resulting in all males at twenty-nine degrees Celsius and all

                                    females at twenty-six to twenty-seven degrees Celsius.  Hatchlings will be between 3.7 and 3.8 cm snout to vent plus their 7.5 cm tail.

                                   They will almost immediately start eating rocks, sand, plants, and insects. The adolescent will remain solitary for the first two months

                                   and by four months live in a gregarious group with a dominant male, several females and some subordinate adolescent males

                                   (sub-males).

                       

 

General

 

 

Unique behavior(s): The agama is mostly a docile lizard except for a male who defends his territory. There are several identifiable behaviors in this species

                                    (head nod, head bob, challenge display, threat display, fighting, and basking). The head nod is when A. agama repeatedly raises and

                                    lowers his head, usually seen at the end of movements, possibly to show male position of individuals. Head bobbing, also known as

                                    push-ups, is the raising and lowering of the head and chest. This is done in an alert posture, it also occurs in the reproductive behavior

                                    of the male. Shown to females when in reproductive colors, one to two begins courtship. The challenge display is shown by the male

    to intruding males or sub-males showing reproductive color. This is only seen in territory situations. The threat display is the rapid up

                                    and down movement of the head with the gular sac fully extended. The whole body raises and lowers.  During fighting, males display

                                    different colors, usually a dark brown head and a pale blue-grey gular pouch is displayed to show intention. Fighting is a series of

                                    bluffs, threats and combat. The challenge occurs when a sub-male or intruding male of reproduction color comes into a territory. The

                                    resident male will challenge from a display post showing the gular pouch while head bobbing. The intruder will react by retreating or

                                    staying and displaying. If the intruder stays then the male will charge to within two feet and will change colors and threaten again, he

                                   will then rush within six inches and will side hop with mouth open. The males will then reverse directions and strike each other with

                                   their tails. Basking occurs mainly in the morning between ten and noon, when A. agama has a darker dorsal coloration than later in the

                                   day. The dominant male will have the best, most elevated site with the sub-males having the next best followed by the females.

Coloration: The dominant male has a red head and tail, blue body and limbs during the day. At night the females, subordinate males, and dominant males

                     are brownish. The head is triangular with a distinct neck and a long tapering tail that cannot be regenerated. There is a spiny appearance due to

                     keeled scales. Eyes are round with movable eyelids.

Diet: Agama agama are primarily insectivores, however A. agama have been known to eat small mammals, small reptiles, and vegetation such as flowers,

          grasses, and fruits. Their diet consists of mainly ants, grasshoppers, beetles, and termites. A. agama is a sit and wait predator. Hunting by vision, it

          sits in vegetation, under a rock outcropping, or in the shade and waits until an insect or small mammal walks by and then will chase the prey. They

          catch their prey by using a tongue with a tip covered by mucous glands; this aids the lizard in holding onto small prey such as ants and termites.

 

 

Sources

 

Alden, Peter C. et al. 1995. National Audubon Society Field Guide to African Wildlife.  Alfred A. Knopf, Inc., New York.

Crews, David, Gustafson, J.E. and Tokarz, R.R. 1983. Physiobiology of Parthnogenesis. Pp. 205-232 in Raymond Huey,

Eric Pianka and Thomas Schoener, ed., Lizard Ecology. Studies of a Model Organism.. Harvard University Press, Cambridge,

Mass. and London, England.

Harris , Vernon A. . 1964. The Life of the Rainbow Lizard. Hutchinson Tropical Monographs, London, England.

Porter, Warren and C. Richard Tracy. 1983. Biophysical Analysis of Energetics, Time-Space Utilization, and Distributional

Limits. Pp. 55-83 in R Huey, E Pianka and T Schoener, ed., Lizard Ecology. Studies of a Model Organism.. Harvard

University Press, Cambridge, Mass. and London, England.

Regal , Philip. 1983. The Adaptive Zone Behavior of Lizards. Pp. 105-118 in Raymond Huey, Eric Pianka and Thomas

Schoener, ed., Lizard Ecology. Studies of a Model Organism. Harvard University Press, Cambridge, Mass. and London,

England.

Simon , Carol. 1983. A Review of Lizard Chemoreception.. Pp. 119-133 in Raymond Huey, Eric Pianka and Thomas

Schoener, ed., Lizard Ecology. Studies in a Model Organism.. Harvard University Press, Cambridge, Mass. and London,

England.

Stamps , Judy. 1983. Sexual Selection, Sexual Dimorphism, and Territoriality. Pp. 169-204 in Raymond Huey, Eric Pianka

and Thomas Schoener, ed., Lizard Ecology. Studies in a Model Organism.. Harvard University Press, Cambridge, Mass. and

London, England.