Sexual dimorphism is the condition where sexes of the same species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is monomorphism, when both biological sexes are phenotypically indistinguishable from each other.
Anolis carolinensis or green anole is a tree-dwelling species of anole lizard native to the southeastern United States and introduced to islands in the Pacific and Caribbean. A small to medium-sized lizard, the green anole is a trunk-crown ecomorph and can change its color to several shades from brown to green.
The sand lizard is a lacertid lizard distributed across most of Europe from France and across the continent to Lake Baikal in Russia. It does not occur in European Turkey. Its distribution is often patchy. In the northern extremes of the sand lizard's distribution, such as along the southern English coast of Great Britain, it can only survive by inhabiting seaside heathlands, where the ground temperature is sufficiently elevated from the Sun's rays; the warmth is also critical to the lizard being able to successfully incubate their eggs, which are laid in sand.
The viviparous lizard, or common lizard, is a Eurasian lizard. It lives farther north than any other species of non-marine reptile, and is named for the fact that it is viviparous, meaning it gives birth to live young. Both "Zootoca" and "vivipara" mean "live birth", in (Latinized) Greek and Latin respectively. It was called Lacerta vivipara until the genus Lacerta was split into nine genera in 2007 by Arnold, Arribas & Carranza.
The common side-blotched lizard is a species of side-blotched lizard in the family Phrynosomatidae. The species is native to dry regions of the western United States and northern Mexico. It is notable for having a unique form of polymorphism wherein each of the three different male morphs utilizes a different strategy in acquiring mates. The three morphs compete against each other following a pattern of rock paper scissors, where one morph has advantages over another but is outcompeted by the third.
Gambelia sila, commonly known as the blunt-nosed leopard lizard, is a species of lizard in the family Crotaphytidae. The species is endemic to southern California.
Urosaurus ornatus, commonly known as the ornate tree lizard, is a species of lizard in the family Phrynosomatidae. The species is native to the southwestern United States and northwestern Mexico. The species, which was formerly called simply the "tree lizard", has been used to study physiological changes during the fight-or-flight response as related to stress and aggressive competition. Its life history and costs of reproduction have been documented in field populations in New Mexico and Arizona. This species has been fairly well studied because of its interesting variation in throat color in males that can correlate with different reproductive strategies,
The Great Basin collared lizard, also known commonly as the desert collared lizard or the Mojave black-collared lizard, is a species of lizard in the family Crotaphytidae. The species is endemic to the Western United States.
The eastern fence lizard is a medium-sized species of lizard in the family Phrynosomatidae. The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, gravid lizard, northern fence lizard or pine lizard. It is also referred to colloquially as the horn-billed lizard. One of its most notable behaviors is that of its escape behavior when encountering fire ants.
Acanthodactylus erythrurus, commonly known as the spiny-footed lizard, is a species of lizard in the family Lacertidae. The species is endemic to northwestern Africa and the Iberian Peninsula. It is considered to be the fastest member of the family Lacertidae. Its common name refers to the spines that are arranged like a comb on the toes of its hind legs.
Podarcis hispanicus, also known as Iberian wall lizard, is a small wall lizard species of the genus Podarcis. It is found in the Iberian peninsula, in northwestern Africa and in coastal districts in Languedoc-Roussillon in France. In Spanish, this lizard is commonly called lagartija Ibérica.
Oligosoma alani,, also known as the robust skink is the largest endemic skink to New Zealand. The robust skink is in the family Scincidae and found in the protected nature reserves of the Mercury Islands in the North Island of New Zealand. The robust skink has an at risk - recovering conservation status.
Iberolacerta cyreni, commonly known as the Cyren's rock lizard, is a species of lizard in the family Lacertidae. The species is endemic to central Spain and is currently listed as endangered by the IUCN due to global warming. I. cyreni has evolved to exhibit key behavioral characteristics, namely individual recognition, in which a lizard is able to identify another organism of the same species, as well as thermoregulation.
The collared brown lemur, also known as the red-collared brown lemur or red-collared lemur, is a medium-sized strepsirrhine primate and one of twelve species of brown lemur in the family Lemuridae. It is only found in south-eastern Madagascar. Like most species of lemur, it is arboreal, moving quadrupedally and occasionally leaping from tree to tree. Like other brown lemurs, this species is cathemeral, lives in social groups, primarily eats fruit, exhibits sexual dichromatism, and does not demonstrate female dominance. The species is listed as Endangered by the International Union for Conservation of Nature (IUCN) and is threatened primarily by habitat loss.
Sexual dimorphism describes the morphological, physiological, and behavioral differences between males and females of the same species. Most primates are sexually dimorphic for different biological characteristics, such as body size, canine tooth size, craniofacial structure, skeletal dimensions, pelage color and markings, and vocalization. However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates and tarsiers are monomorphic.
Uracentron flaviceps, the tropical thornytail iguana or Amazon thornytail iguana is an elusive species of medium-sized arboreal lizard found in the tropical lowlands of the Amazon Rainforest. The species was described by French zoologist Alphone Guichenot in 1855. They are considered to be ant specialists and exhibit communal nesting and a harem-style breeding system in which one male mates with and attends to multiple females. Study of this species has been impeded by difficulties collecting and observing them.
Gonatodes albogularis, which has been called a number of vernacular names in English, is a smallish species of gecko found in warm parts of Central and South America, Cuba, Hispaniola and Jamaica. They prefer to live in tropical dry forest habitats. It is sexually dimorphic: the male is colourful, while the female is a more drab grey. The fingers do not have lamellar pads for climbing smooth surfaces like many other geckos but instead have normal claws like most lizards. At one time the species had a breeding population in southern Florida, especially Key West, but this population appears to have died out by the early 1990s. They are believed to be able to tell the difference between brightness and hues of conspecifics. Males are incredibly aggressive with territory defense against both other males and potential predators.
Sexual selection in scaled reptiles studies how sexual selection manifests in snakes and lizards, which constitute the order Squamata of reptiles. Each of the over three thousand snakes use different tactics in acquiring mates. Ritual combat between males for the females they want to mate with includes topping, a behavior exhibited by most viperids in which one male will twist around the vertically elevated fore body of its opponent and forcing it downward. It is common for neck biting to occur while the snakes are entwined.
Diploderma swinhonis, also known commonly as the Taiwan japalure, Swinhoe's japalure, Swinhoe's lizard, and Swinhoe's tree lizard, is a species of lizard in the family Agamidae. The species is native to Taiwan. It is considered an invasive alien species in Japan after likely being transported from Taiwan by humans. A foraging ambush predator, this lizard preys primarily on arthropods and thus remains at the bottom of forests perched on trees where sunlight is present. D. swinhonis is not a major threat to humans and is able to adapt to a variety of habitats, including urban environments. The male D. swinhonis is physically distinct from the female, with its body size being much larger and having a yellow stripe. This species sexually reproduces on a seasonal basis and hibernates during the winter time.
Anolis aquaticus, commonly known as the water anole, is a semi-aquatic species of anole, a lizard in the family Dactyloidae, native to southwestern Costa Rica and far southwestern Panama. The species demonstrates adaptations that allows it to spend periods of time underwater up to approximately a quarter of an hour, forming an air bubble which clings to its head and serves to recycle the animal's air supply while it spends time beneath the surface. Although highly unusual, similar adaptions and behavior are found in other species of semi-aquatic anoles.
