Objectives
Reptiles: Agama Lizard (Agama agama)
Phylum: Chordata
Sub-phylum: Vertebrata
The scientific name of the Agama lizard
The term "Agama lizard" refers to various species within the genus Agama. Therefore, the scientific name can vary depending on the specific species of Agama lizard being referred to. Here are some examples:
- Common Agama - Agama agama
- Bearded Agama - Agama stellio
- Rainbow Agama - Agama impalearis
- Kenyan Rock Agama - Agama lionotus
- Long-tailed Agama - Agama longicauda
- Saharan Agama - Agama saharae
Each species has its own unique scientific name, reflecting its specific classification within the Agama genus.
Habitat: Lizards live in desert, grassland, rainforest, around homes, building, trees and rocks.
Agama lizard is sometimes called rainbow lizard because of the colorful displays put on by the adult male. Agama show sexual dimorphism (difference in appearance among male and female). The female possesses brown head with green spots and brown body with yellow patches. The dominant male (adult male) has bright red or yellow head, dark blue body and the tail with different colors.
Structure of Agama Lizard
The body is covered by dry, horny, overlapping scales. It has a triangular head separated from the trunk by a short neck, a long tail and two eyes. Each eye is protected by movable eyelids; a transparent fold of skin called nictitating membrane and a ridge of hard scales. Behind the eyes are well-developed circular ear-drums or tympanum.
It has a terminal mouth with homodont dentition. Above the mouth is a pair of nostrils.
The male possesses a fold of skin called gular fold, below the chin, which is lowered during courtship or frightened. It also has a scaly growth of skin called nuchal crest above the neck. It is raised during fighting.
Two pairs of limbs arise from the trunk. The limbs are shot and stout with five digits which are not webbed. The hind-limbs are longer than the fore-limbs.
The trunk terminates in a long tapering tail. Many lizards can detach their tails to escape from predators, an act called autotomy, but this ability is not shared by all lizards.
Movement in Agama Lizard
Agama lizard can run, climb and cling using strong, clawed digits of it limbs. It run quickly on its hind limb for short distances. The tail helps in balance and movement.
The limbs are unable to support the body clearly of the ground at rest. This is because the limbs extend out horizontally and not directly under the trunk as in mammals.
What Do Agama Lizards Eat?
Agama lizards are primarily insectivores, meaning their diet mainly consists of insects. However, their diet can vary depending on the species, habitat, and availability of food sources. Here’s a detailed look at what Agama lizards eat:
1. Insects
- Common Insects: Agama lizards commonly consume a wide range of insects, including ants, beetles, flies, termites, and grasshoppers. These insects provide essential proteins, fats, and nutrients that are crucial for their growth and energy.
- Feeding Behavior: They actively forage for insects, often seen darting after their prey with quick, agile movements. The lizards use their keen eyesight to spot and capture insects.
2. Arachnids
- Spiders and Scorpions: In addition to insects, Agama lizards may also eat arachnids such as spiders and scorpions. These creatures offer additional protein and are commonly found in their natural habitats.
- Diet Variation: The inclusion of arachnids in their diet can depend on the specific Agama species and its habitat.
3. Vegetation
- Plant Matter: Some Agama lizards occasionally consume plant matter, including leaves, fruits, and flowers. This is particularly true for species that have adapted to more diverse diets.
- Nutritional Value: Plant material provides fiber and some vitamins but is not the primary food source. It is often eaten in smaller quantities compared to insects.
4. Small Vertebrates
- Occasional Prey: While not a staple, larger Agama lizards might occasionally consume small vertebrates such as smaller lizards or amphibians. This is more common in larger species with a broader diet.
- Opportunistic Feeding: Such consumption usually occurs when insects are scarce or if the opportunity presents itself.
5. Supplemental Food
- In Captivity: When kept as pets, Agama lizards are often fed a varied diet that can include commercially available insectivore diets, such as cricket meal, mealworms, and specially formulated lizard foods. Reptiles Magazine provides guidance on maintaining a balanced diet for captive Agama lizards.
Nutritional Needs
Agama lizards require a diet that provides a balance of proteins, fats, and vitamins. Insects are rich in protein and essential nutrients, while plant matter can offer additional vitamins and minerals. Proper feeding is crucial for maintaining their health, growth, and reproductive success.
Respiration in Agama Lizard
Excretion in Agama Lizards
Excretion is performed mainly by two small kidneys. Uric acid is the main nitrogenous waste product excreted by lizards. Reptile kidneys are unable to produce liquid urine; this is because they lack a specialized structure called a loop of Henle.
The nitrogenous waste is excreted as white, solid substance along with the faeces.
The solid uric acid produced is an adaptation of water conservation in lizards.
Reproduction in Lizards
1. Courtship and Mating
The male develops dramatic colorful markings; the head, neck and tail turn bright orange, and the body dark blue.
The male approaches the female from behind and bob the head to attract her.
The female curved her back with the tail and head raised. The male chased, grasps and mount on her. They pair at 90 degrees in order to bring their cloacae together.
The male pushes the base of his tail onto her cloaca, inserting his hemi-penis and introduce sperms into the female. Fertilization is internal.
2. Egg Laying and Hatching
The female lays the fertilized eggs in a hole she digs with her claws and cover the eggs with soil. The eggs are hatch within eight to ten weeks.
The young lizards become active and immediately start eating sand, plants, and insects.
Lizard Territory
A territory consists of one adult male, several adult females and young of both sexes. The dominant male defends his territory.
It displays several behaviors, such challenge, threat and fighting.
The challenge display is shown in a situation where young male showing orange color (or reproductive color) is chased out of the territory.
It challenges or fights if an intruder tries to mate with his females.
The threat is display by rapid up and down movement of the head with the gular fold fully extended. The whole body raises and lowers.
Adaptation of the Lizard to its Environment
1. Presence of lungs for respiration.
2. Clawed digit which allows lizards to climb.
3. It has well developed eye for detecting prey.
4. Long mucous tongue for trapping prey.
5. Dry scaly skin for protection against water loss
6. Long tail for balancing while moving
Features of Evolutionary Advancement of Lizards over Frogs or Toads
1. Presence of strong legs with clawed digit for climbing and running quickly on land.
2. Lizards lay shelled eggs that for prevention of desiccation
3. Lizards are diurnal animals. They are adapted to daylight conditions, with color vision and more advanced visual depth than in amphibians.
4. Respiration in lizards occurs only through the lung but amphibians’ respiration occurs in more primitive structures such as the skin and mouth in addition to the lung.
Differences Between Male and Female Agama Lizards
Male and female Agama lizards often exhibit distinct differences in physical appearance, behavior, and reproductive roles. These differences can vary somewhat between species, but here are some common distinctions:
1. Physical Appearance
- Coloration:
- Males: In many Agama species, males are more brightly colored than females. For example, in the Common Agama (Agama agama), males often have vivid red or orange heads and bright blue or green bodies. These vibrant colors are used to attract females and establish territory.
- Females: Females typically have more subdued, less colorful patterns. They may have duller or more uniform coloration that helps with camouflage and avoiding predators.
- Bearded Agama (Agama stellio): Males often have a more pronounced and colorful beard compared to females, which they use during mating displays and territorial disputes.
- Size:
- Males: In many species, males are larger and have more robust body structures. They may also have larger heads and more pronounced throat flaps or crests used for display.
- Females: Females are usually smaller and more slender. This size difference can be particularly noticeable during the breeding season when males exhibit more dramatic physical displays.
2. Behavior
- Territorial Displays:
- Males: Males are often more territorial and engage in elaborate displays to attract mates and ward off rivals. These displays can include head bobbing, puffing out their throats, and showing off their colorful body parts.
- Females: Females are generally less involved in territorial behaviors and are more focused on nesting and caring for eggs.
- Breeding Behavior:
- Males: During mating season, males perform courtship rituals to attract females. These rituals may involve complex displays of color and movement to demonstrate their fitness and dominance.
- Females: Females are usually less active in displays and spend more time choosing mates based on these displays. Once mated, females are responsible for laying and guarding eggs.
3. Reproductive Roles
- Males: Males contribute sperm to fertilize eggs and play a role in courtship and territorial defense. They often exhibit behaviors that highlight their fitness and attractiveness to potential mates.
- Females: Females are responsible for laying eggs and may show nesting behaviors. They may also be involved in guarding the eggs or providing initial care for the hatchlings in some species.
4. Crest and Throat Flap Development
- Males: In species like the Bearded Agama (Agama stellio), males have a more developed and colorful throat flap (or beard), which is used during courtship and territorial displays.
- Females: Females generally have a less prominent throat flap and may not exhibit the same level of color variation.
|
Male lizard |
Female lizard |
|
Large in size |
Small in size |
|
More
prominent nuchal crest and gular fold |
Less prominent nuchal
crest and gular fold |
|
Orange head |
Brown head with green spots |
|
Brightly
colored |
Usually, dull colored |
|
Hemi-penis present |
Absence of hemi-penis |
|
Dark
blue trunk and tail with different colors; blue at base, orange in the middle
and black at the tip |
Brown trunk with yellow
spots and brown tail |
Difference between the External Features of Lizard and Toad
|
Lizard |
Toad |
|
Long and narrow trunk |
Short and wide trunk |
|
Dry
scaly skin |
Moist skin without scales |
|
Presences of neck and tail |
Absences of neck and tail |
|
Forelimb
has five digits |
Forelimb has four digits |
|
Presence of teeth |
Absences of teeth |
|
Hind-limbs
are not webbed |
Hind-limbs are webbed |
|
Less prominent tympanum membrane and eyes
are not bulging |
Prominent tympanum membrane and bulging eyes |
Different Types of Agama Lizards
Agama lizards belong to the family Agamidae, which comprises a diverse group of lizards found primarily in Africa, with some species also found in parts of Asia. Known for their striking colors and unique behaviors, Agama lizards are classified into several genera and species. Here’s an overview of some prominent types of Agama lizards:
1. Common Agama (Agama agama)
- Description: Also known as the Red-headed Agama, this species is widely distributed across Africa. The males are particularly notable for their bright red heads, while their bodies are often blue or green.
- Habitat: They are adaptable and can be found in various habitats including savannas, open woodlands, and urban areas.
- Behavior: They are often seen basking on rocks and are known for their territorial behavior. Males perform elaborate displays to attract females and ward off rivals.
- More Information: Learn more about the Common Agama on Reptiles Magazine.
2. Bearded Agama (Agama stellio)
- Description: Commonly referred to as the Stellion or Bearded Agama, this species features a distinctive beard-like flap of skin around its neck. Males are known for their colorful throat and body displays.
- Habitat: They inhabit rocky areas, cliffs, and deserts across North Africa and the Middle East.
- Behavior: They are arboreal and terrestrial, often seen sunbathing and foraging on rocky surfaces. The beard is used in mating displays and to intimidate predators.
- More Information: Explore more about the Bearded Agama on The Reptile Database.
3. Rainbow Agama (Agama impalearis)
- Description: Known for its vibrant and iridescent coloration, the Rainbow Agama exhibits a range of colors, including blues, greens, and purples. The males are particularly colorful.
- Habitat: This species is native to the savannas and open woodlands of East Africa.
- Behavior: Males use their bright colors to attract mates and establish territory. They are often found basking in the sun.
- More Information: For additional details, visit African ReptilesAfrican Reptiles.
4. Kenyan Rock Agama (Agama lionotus)
- Description: The Kenyan Rock Agama is distinguished by its bright orange head and blue body. It is one of the more colorful species within the Agama genus.
- Habitat: This lizard is commonly found in rocky outcrops and open areas in Kenya and neighboring regions.
- Behavior: It is known for its climbing abilities and often uses rocks for basking and territorial displays.
- More Information: Read more about the Kenyan Rock Agama on The Reptile Zone.
5. Long-tailed Agama (Agama longicauda)
- Description: Characterized by its notably long tail, this species also exhibits a variety of colors depending on the region and individual.
- Habitat: They are found in a range of habitats from semi-arid areas to forest edges across East Africa.
- Behavior: The long tail helps with balance and maneuverability in climbing and foraging.
- More Information: For more details, visit African Wildlife Foundation.
6. Saharan Agama (Agama saharae)
- Description: This species is adapted to the arid environments of the Sahara Desert. It has a more subdued coloration, typically blending with its sandy surroundings.
- Habitat: As its name suggests, it is native to the Sahara Desert region.
- Behavior: The Saharan Agama is well-adapted to desert life, using burrows and crevices to avoid extreme temperatures.
- More Information: Discover more about the Saharan Agama at Desert Wildlife.
The Role of Agama Lizards in Their Ecosystems
Agama lizards, found across various habitats in Africa and parts of Asia, play significant roles in their ecosystems. Their diverse activities contribute to ecological balance and health. Here’s a look at the key roles Agama lizards play in their environments:
1. Insect Population Control
- Predators: Agama lizards are primarily insectivorous, feeding on a variety of insects such as ants, beetles, termites, and flies. By consuming these insects, they help control their populations, preventing them from becoming pests that could damage plants or spread diseases.
- Ecosystem Impact: This natural pest control is vital for maintaining the health of plant communities and reducing the spread of insect-borne diseases. For instance, by eating mosquitoes, Agama lizards help reduce the risk of malaria and other mosquito-borne illnesses.
2. Food Source for Other Animals
- Prey: Agama lizards serve as prey for a variety of predators, including birds, mammals, and larger reptiles. Their presence supports the food web, providing essential nutrients to these higher trophic level animals.
- Ecological Balance: By being a key prey item, Agama lizards help sustain populations of their predators, contributing to the balance of the food chain in their ecosystems.
3. Soil and Habitat Modification
- Burrowing: Some Agama lizards dig burrows or use existing ones to create shelters. These burrows can alter the physical environment, influencing soil structure and aeration.
- Habitat Creation: The burrows and rock crevices used by Agama lizards can also serve as habitats for other small organisms, promoting biodiversity within their ecosystems.
4. Seed Dispersal
- Plant Interaction: Although not a primary role, Agama lizards occasionally consume fruits and other plant material. The seeds they ingest can be dispersed through their droppings, aiding in plant propagation and contributing to the growth of new plant life in their habitats.
5. Biological Indicators
- Environmental Health: Agama lizards, like many reptiles, are sensitive to changes in their environment. Their health and population trends can indicate the overall condition of their habitat, including factors like pollution, habitat degradation, and climate change.
- Conservation: Monitoring Agama lizard populations can provide valuable insights into ecosystem health and help guide conservation efforts to protect and restore their habitats.
6. Behavioral Influence
- Territorial Displays: Males of many Agama species perform colorful displays and territorial behaviors. These behaviors not only help in mating but also play a role in maintaining social structure and reducing conflict among individuals.
- Community Dynamics: The interactions and behaviors of Agama lizards contribute to the social dynamics and stability of their populations, influencing community structure within their ecosystems.
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