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Duck is the common name for numerous species of waterfowl in the family Anatidae. ... Southern resident species typically show less sexual dimorphism, ...
Sexual dimorphism is the condition where sexes of the same species exhibit different morphological characteristics, including characteristics not directly involved in reproduction. [1] The condition occurs in most dioecious species, which consist of most animals and some plants.
Animal non-reproductive sexual behavior encompasses sexual activities that non-human animals participate in which do not lead to the reproduction of the species. Although procreation continues to be the primary explanation for sexual behavior in animals, recent observations on animal behavior have given alternative reasons for the engagement in sexual activities by animals. [1]
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. [6] [7] Sexual reproduction also occurs in some unicellular eukaryotes. [2] [8] Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea.
Sexual coercion among animals is the use of violence, threats, harassment, and other tactics to help them forcefully copulate. [1] Such behavior has been compared to sexual assault, including rape, among humans. [2] In nature, males and females usually differ in reproductive fitness optima. [3]
The lake duck grows to 36–46 centimetres (14–18 in). Females weigh 510–700 grams (18–25 oz) and males 600–850 grams (21–30 oz). Males can be distinguished from Andean duck (Oxyura ferruginea), a similar species, by being smaller and having a flatter head. [2] Female ducks have an anti-corkscrew vagina made for difficult penetration.
In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract. [1] [2] This is an aspect of mating.