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In zoology, copulation is animal sexual behavior in which a male introduces
sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...
into the female's body, especially directly into her reproductive tract. This is an aspect of mating. Many animals that live in water use external fertilization, whereas internal fertilization may have developed from a need to maintain
gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...
s in a liquid medium in the Late Ordovician epoch. Internal fertilization with many vertebrates (such as all
reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
s, some fish, and most
bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s) occurs via
cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
l copulation, known as cloacal kiss (see also hemipenis), while
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s copulate vaginally, and many
basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...
vertebrates reproduce sexually with external fertilization.


In spiders and insects

Spiders are often confused with insects, but they are not insects; instead, they are
arachnid Arachnida () is a class of joint-legged invertebrate animals ( arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and ...
s. Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on to it. He then stores the sperm in reservoirs on his large pedipalps, from which he transfers sperm to the female's genitals. The females can store sperm indefinitely. For primitive insects, the male deposits spermatozoa on the substrate, sometimes stored within a special structure; courtship involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation. In groups that have reproduction similar to spiders, such as dragonflies, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified sternites on the second abdominal segment. In advanced groups of insects, the male uses its
aedeagus An aedeagus (plural aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison ...
, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a '' spermatophore'') into the female's reproductive tract.


In mammals

Sexual behavior can be classified into behavioral states associated with reward motivation (" wanting"), reward consummation aka pleasure ("liking"), and
satiety Satiety ( ) is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of hunger. It is a state which induces meal termination.Hetherington, M.Sensory-specific satiety and its importance in meal termination ''Neuro ...
("inhibition"); these behavioral states are regulated in mammals by reward-based sexual learning, fluctuations in various neurochemicals (i.e.,
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...
sexual desire aka "wanting"; norepinephrine
sexual arousal Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind as ...
;
oxytocin Oxytocin (Oxt or OT) is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. It plays a role in social bonding, reproduction, childbirth, and the period after childbirth. Oxytocin ...
and
melanocortins The melanocortins are a family of neuropeptide hormones which are the ligands of the melanocortin receptorsEricson, M.D., et al., ''Bench-top to clinical therapies: A review of melanocortin ligands from 1954 to 2016.'' Biochim Biophys Acta Mol Basi ...
sexual attraction), and gonadal hormone cycles and further influenced by sex pheromones and motor reflexes (i.e.,
lordosis behaviour Lordosis behavior (), also known as mammalian lordosis (Greek lordōsis, from ''lordos'' "bent backward") or presenting, is the naturally occurring body posture for sexual receptivity to copulation present in females of most mammals including rod ...
) in some mammals. These behavioral states correlate with the phases of the human sexual response cycle: motivation − excitement; consummation − plateau and orgasm; satiety − refraction. Sexual learning (a form of associative learning) occurs when an animal starts to associate bodily features, personality, contextual cues, and other stimuli with genitally-induced sexual pleasure. Once formed, these associations in turn impinge upon both sexual wanting and sexual liking. In most female mammals, the act of copulation is controlled by several innate neurobiological processes, including the motor sexual reflex of lordosis.PFAFF Donald W. , SCHWARTZ-GIBLIN Susan, MACCARTHY Margareth M. , KOW Lee-Ming : Cellular and molecular mechanisms of female reproductive behaviors, in KNOBIL Ernest, NEILL Jimmy D. : The physiology of reproduction, Raven Press, 2nd edition, 1994 In males, the act of copulation is more complex, because some learning is necessary, but the innate processes (retrocontrol of penis intromission in the vagina, rhythmic movement of the pelvis, detection of female pheromones) are specific to copulation. These innate processes direct heterosexual copulation.MEISEL Robert L. , SACHS Benjamin D. : The physiology of male sexual behavior. in KNOBIL Ernest, NEILL Jimmy D. The physiology of reproduction, Raven Press, 2nd edition, 1994 Female lordosis behaviour became secondary in
hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ea ...
and is non-functional in humans.Dixson A.F
Primate sexuality: Comparative studies of the Prosimians, Monkeys, Apes, and Human Beings
Oxford University Press, 2nd edition, 2012.
Mammals usually copulate in a dorso-ventral posture, though there are some primate species that copulate in a ventro-vental posture. Most mammals possess a vomeronasal organ that is involved in pheromone detection, including sex pheromones. Despite the fact that humans do not possess this organ, adult humans appear to be sensitive to certain mammalian pheromones that putative pheromone receptor proteins in the olfactory epithelium are capable of detecting. While sex pheromones clearly play a role in modifying sexual behavior in some mammals, the capacity for general pheromone detection and the involvement of pheromones in regulating human sexual behavior has not yet been determined. The duration of copulation varies significantly between mammal species, and may be correlated with body mass, lasting longer in small mammals than in large mammals.Stallmann, Robert R., and A. H. Harcourt.
Size matters: the (negative) allometry of copulatory duration in mammals
" Biological Journal of the Linnean Society 87.2 (2006): 185-193.


See also

* Pelvic thrust


Notes


References


Bibliography

* * Møller, A. P., and T. R. Birkhead.
Copulation behaviour in mammals: evidence that sperm competition is widespread
" Biological Journal of the Linnean Society 38.2 (1989): 119–131. * Birkhead, Timothy R., L. Atkin, and A. P. Møller.
Copulation behaviour of birds
" Behaviour 101.1 (1987): 101–138. * * * * * *Carlson, Debra A
Reproductive biology of the coyote (Canis latrans): integration of behavior and physiology
Utah State University, 2008. *Castro, Ana Mafalda Lopes Sardica Velez
Mexican gray wolf courtship and mating: behavior & basic endocrinology during breeding season
Diss. Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016. * Szykman, Micaela, et al.
Courtship and mating in free-living spotted hyenas.
Behaviour 144.7 (2007): 815–846. * Dixson, Alan F.
Baculum length and copulatory behavior in primates.
American Journal of Primatology 13.1 (1987): 51–60. {{Animal sexual behavior Animal sexuality Ethology Mammalian sexuality Physiology Sex positions