101-523: Gelfand is a surname meaning " elephant " in the Yiddish language . Notable people with the surname include: Alexander Gelfond (1906–1968), Soviet mathematician Michael Gelfond , American computer scientist See also [ edit ] Gelfand Helfand Helfant [REDACTED] Surname list This page lists people with the surname Gelfond . If an internal link intending to refer to
202-434: A meta-analysis , substitution therapy with testosterone results in a significant reduction of inflammatory markers. These effects are mediated by different mechanisms with synergistic action. In androgen-deficient men with concomitant autoimmune thyroiditis , substitution therapy with testosterone leads to a decrease in thyroid autoantibody titres and an increase in thyroid's secretory capacity (SPINA-GT). Testosterone
303-409: A Y. The female's clitoris may be 40 cm (16 in). The vulva is found lower than in other herbivores, between the hind legs instead of under the tail. Determining pregnancy status can be difficult due to the animal's large belly. The female's mammary glands occupy the space between the front legs, which puts the suckling calf within reach of the female's trunk. Elephants have a unique organ,
404-423: A child is in distress has been found to be indicative of fathering styles. If a father's testosterone levels decrease in response to hearing their baby cry, it is an indication of empathizing with the baby. This is associated with increased nurturing behavior and better outcomes for the infant. Testosterone levels play a major role in risk-taking during financial decisions. Higher testosterone levels in men reduce
505-449: A day. Elephants tend to stay near water sources. They have morning, afternoon, and nighttime feeding sessions. At midday, elephants rest under trees and may doze off while standing. Sleeping occurs at night while the animal is lying down. Elephants average 3–4 hours of sleep per day. Both males and family groups typically move no more than 20 km (12 mi) a day, but distances as far as 180 km (112 mi) have been recorded in
606-504: A faster gait similar to running. In walking, the legs act as pendulums, with the hips and shoulders moving up and down while the foot is planted on the ground. The fast gait does not meet all the criteria of running, since there is no point where all the feet are off the ground, although the elephant uses its legs much like other running animals, and can move faster by quickening its stride. Fast-moving elephants appear to 'run' with their front legs, but 'walk' with their hind legs and can reach
707-494: A higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not the level of cortisol in the female body, and hormonal contraceptives may affect the variation in testosterone response to sexual thoughts. Testosterone may prove to be an effective treatment in female sexual arousal disorders , and
808-494: A human brain. It is the largest of all terrestrial mammals. While the elephant brain is larger overall, it is proportionally smaller than the human brain . At birth, an elephant's brain already weighs 30–40% of its adult weight. The cerebrum and cerebellum are well developed, and the temporal lobes are so large that they bulge out laterally. Their temporal lobes are proportionally larger than those of other animals, including humans. The throat of an elephant appears to contain
909-779: A long proboscis called a trunk, tusks , large ear flaps, pillar-like legs, and tough but sensitive grey skin. The trunk is prehensile , bringing food and water to the mouth and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears and convex or level backs. Elephants are scattered throughout sub-Saharan Africa , South Asia, and Southeast Asia and are found in different habitats, including savannahs , forests, deserts, and marshes . They are herbivorous , and they stay near water when it
1010-475: A male and female brain that may be due to different testosterone levels, one of them being size: the male human brain is, on average, larger. Testosterone does not appear to increase the risk of developing prostate cancer . In people who have undergone testosterone deprivation therapy, testosterone increases beyond the castrate level have been shown to increase the rate of spread of an existing prostate cancer. Conflicting results have been obtained concerning
1111-477: A model for studying clinical populations among humans with sexual arousal deficits such as hypoactive sexual desire disorder . Every mammalian species examined demonstrated a marked increase in a male's testosterone level upon encountering a novel female. The reflexive testosterone increases in male mice is related to the male's initial level of sexual arousal. In non-human primates, it may be that testosterone in puberty stimulates sexual arousal, which allows
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#17327902314681212-548: A pouch where it can store water for later use. The larynx of the elephant is the largest known among mammals. The vocal folds are anchored close to the epiglottis base. When comparing an elephant's vocal folds to those of a human, an elephant's are proportionally longer, thicker, with a greater cross-sectional area. In addition, they are located further up the vocal tract with an acute slope. The heart of an elephant weighs 12–21 kg (26–46 lb). Its apex has two pointed ends, an unusual trait among mammals. In addition,
1313-418: A protective crust. Elephants have difficulty releasing heat through the skin because of their low surface-area-to-volume ratio , which is many times smaller than that of a human. They have even been observed lifting up their legs to expose their soles to the air. Elephants only have sweat glands between the toes, but the skin allows water to disperse and evaporate, cooling the animal. In addition, cracks in
1414-441: A response to previously neutral stimuli when conditioned to become sexual in male rats. This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction. In men, higher levels of testosterone are associated with periods of sexual activity. Men who watch
1515-434: A sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films. Men who watch sexually explicit films also report increased motivation and competitiveness, and decreased exhaustion. A link has also been found between relaxation following sexual arousal and testosterone levels. Androgens may modulate
1616-541: A single species, Loxodonta africana , but molecular studies have affirmed their status as separate species. Mammoths ( Mammuthus ) are nested within living elephants as they are more closely related to Asian elephants than to African elephants. Another extinct genus of elephant, Palaeoloxodon , is also recognised, which appears to have close affinities with African elephants and to have hybridised with African forest elephants. Over 180 extinct members of order Proboscidea have been described. The earliest proboscideans,
1717-466: A specific person led you to this page, you may wish to change that link by adding the person's given name (s) to the link. Retrieved from " https://en.wikipedia.org/w/index.php?title=Gelfond&oldid=1067763692 " Categories : Surnames Yiddish-language surnames Hidden categories: Articles with short description Short description is different from Wikidata All set index articles Elephant Elephants are
1818-440: A strong grasp. The flexibility of the trunk is aided by the numerous wrinkles in the skin. The African elephants have two finger-like extensions at the tip of the trunk that allow them to pluck small food. The Asian elephant has only one and relies more on wrapping around a food item. Asian elephant trunks have better motor coordination . The trunk's extreme flexibility allows it to forage and wrestle other elephants with it. It
1919-462: A tablet that is placed in the cheek , or by ingestion. Common side effects from testosterone medication include acne , swelling , and breast enlargement in males . Serious side effects may include liver toxicity , heart disease (though a randomized trial found no evidence of major adverse cardiac events compared to placebo in men with low testosterone ), and behavioral changes. Women and children who are exposed may develop virilization . It
2020-661: A top speed of 25 km/h (16 mph). At this speed, most other quadrupeds are well into a gallop, even accounting for leg length. Spring-like kinetics could explain the difference between the motion of elephants and other animals. The cushion pads expand and contract, and reduce both the pain and noise that would come from a very heavy animal moving. Elephants are capable swimmers: they can swim for up to six hours while completely waterborne, moving at 2.1 km/h (1 mph) and traversing up to 48 km (30 mi) continuously. The brain of an elephant weighs 4.5–5.5 kg (10–12 lb) compared to 1.6 kg (4 lb) for
2121-432: A year. As the tusk develops, it is topped with smooth, cone-shaped enamel that eventually wanes. The dentine is known as ivory and has a cross-section of intersecting lines, known as "engine turning", which create diamond-shaped patterns. Being living tissue, tusks are fairly soft and about as dense as the mineral calcite . The tusk protrudes from a socket in the skull, and most of it is external. At least one-third of
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#17327902314682222-418: Is a steroid hormone from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites. It exerts its action through binding to and activation of the androgen receptor . In humans and most other vertebrates , testosterone is secreted primarily by
2323-559: Is a great deal of mutual overlap between them. The relative potency of these effects can depend on various factors and is a topic of ongoing research. Testosterone can either directly exert effects on target tissues or be metabolized by 5α-reductase into dihydrotestosterone (DHT) or aromatized to estradiol (E2). Both testosterone and DHT bind to an androgen receptor; however, DHT has a stronger binding affinity than testosterone and may have more androgenic effect in certain tissues at lower levels. Testosterone effects can also be classified by
2424-409: Is accessible. They are considered to be keystone species , due to their impact on their environments. Elephants have a fission–fusion society , in which multiple family groups come together to socialise. Females (cows) tend to live in family groups, which can consist of one female with her calves or several related females with offspring. The leader of a female group, usually the oldest cow, is known as
2525-559: Is available as a dermal patch . There is no FDA-approved androgen preparation for the treatment of androgen insufficiency; however, it has been used as an off-label use to treat low libido and sexual dysfunction in older women. Testosterone may be a treatment for postmenopausal women as long as they are effectively estrogenized. Falling in love has been linked with decreases in men's testosterone levels while mixed changes are reported for women's testosterone levels. There has been speculation that these changes in testosterone result in
2626-718: Is derived from the Latin word elephas ( genitive elephantis ) ' elephant ' , which is the Latinised form of the ancient Greek ἐλέφας ( elephas ) (genitive ἐλέφαντος ( elephantos )), probably from a non- Indo-European language , likely Phoenician . It is attested in Mycenaean Greek as e-re-pa (genitive e-re-pa-to ) in Linear B syllabic script. As in Mycenaean Greek, Homer used
2727-577: Is more relevant to changes in testosterone levels. Men who produce more testosterone are more likely to engage in extramarital sex. Testosterone levels do not rely on physical presence of a partner; testosterone levels of men engaging in same-city and long-distance relationships are similar. Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women. Fatherhood decreases testosterone levels in men, suggesting that
2828-918: Is occurring since no significant changes have been identified in other parts of the body. The male brain is masculinized by the aromatization of testosterone into estradiol , which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein , which binds the estrogen so that female brains are not affected. Before puberty, effects of rising androgen levels occur in both boys and girls. These include adult-type body odor , increased oiliness of skin and hair, acne , pubarche (appearance of pubic hair ), axillary hair (armpit hair), growth spurt , accelerated bone maturation , and facial hair . Pubertal effects begin to occur when androgen has been higher than normal adult female levels for months or years. In males, these are usual late pubertal effects, and occur in women after prolonged periods of heightened levels of free testosterone in
2929-425: Is particularly beneficial for humans since offspring are dependent on parents for extended periods of time and mothers have relatively short inter-birth intervals. While the extent of paternal care varies between cultures, higher investment in direct child care has been seen to be correlated with lower average testosterone levels as well as temporary fluctuations. For instance, fluctuation in testosterone levels when
3030-417: Is powerful enough to lift up to 350 kg (770 lb), but it also has the precision to crack a peanut shell without breaking the seed. With its trunk, an elephant can reach items up to 7 m (23 ft) high and dig for water in the mud or sand below. It also uses it to clean itself. Individuals may show lateral preference when grasping with their trunks: some prefer to twist them to the left, others to
3131-631: Is recommended that individuals with prostate cancer not use the medication. It can cause harm if used during pregnancy or breastfeeding . 2020 guidelines from the American College of Physicians support the discussion of testosterone treatment in adult men with age-related low levels of testosterone who have sexual dysfunction . They recommend yearly evaluation regarding possible improvement and, if none, to discontinue testosterone; physicians should consider intramuscular treatments, rather than transdermal treatments, due to costs and since
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3232-489: Is similar and known as " evolutionary neuroandrogenic (ENA) theory of male aggression". Testosterone and other androgens have evolved to masculinize a brain to be competitive, even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens, enhance their resource acquiring abilities to survive, attract and copulate with mates as much as possible. The masculinization of
3333-456: Is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts. Married men who engage in bond-maintenance activities such as spending the day with their spouse or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities
3434-417: Is therefore the challenge of competition among males that facilitates aggression and violence. Studies conducted have found direct correlation between testosterone and dominance, especially among the most violent criminals in prison who had the highest testosterone. The same research found fathers (outside competitive environments) had the lowest testosterone levels compared to other males. The second theory
3535-600: Is typically more worn down, as it is shorter and blunter. For African elephants, tusks are present in both males and females and are around the same length in both sexes, reaching up to 300 cm (9 ft 10 in), but those of males tend to be more massive. In the Asian species, only the males have large tusks. Female Asians have very small tusks, or none at all. Tuskless males exist and are particularly common among Sri Lankan elephants . Asian males can have tusks as long as Africans', but they are usually slimmer and lighter;
3636-679: Is used as a medication to treat hypogonadism and breast cancer . Since testosterone levels decrease as men age , testosterone is sometimes used in older men to counteract this deficiency. It is also used illicitly to enhance physique and performance , for instance in athletes . The World Anti-Doping Agency lists it as S1 Anabolic agent substance "prohibited at all times". In general, androgens such as testosterone promote protein synthesis and thus growth of tissues with androgen receptors . Testosterone can be described as having anabolic and androgenic ( virilising ) effects, though these categorical descriptions are somewhat arbitrary, as there
3737-403: Is used as a medication for the treatment of male hypogonadism , gender dysphoria , and certain types of breast cancer . This is known as hormone replacement therapy (HRT) or testosterone replacement therapy (TRT), which maintains serum testosterone levels in the normal range. Decline of testosterone production with age has led to interest in androgen replacement therapy . It is unclear if
3838-564: The Bering Strait into the Holocene, with their latest survival being on Wrangel Island , where they persisted until around 4,000 years ago. Over the course of their evolution, probobscideans grew in size. With that came longer limbs and wider feet with a more digitigrade stance, along with a larger head and shorter neck. The trunk evolved and grew longer to provide reach. The number of premolars, incisors, and canines decreased, and
3939-842: The Early Pleistocene , all non-elephantid probobscidean genera outside of the Americas became extinct with the exception of Stegodon , with gomphotheres dispersing into South America as part of the Great American interchange , and mammoths migrating into North America around 1.5 million years ago. At the end of the Early Pleistocene, around 800,000 years ago the elephantid genus Palaeoloxodon dispersed outside of Africa, becoming widely distributed in Eurasia. Proboscideans were represented by around 23 species at
4040-696: The Etosha region of Namibia. Elephants go on seasonal migrations in response to changes in environmental conditions. In northern Botswana, they travel 325 km (202 mi) to the Chobe River after the local waterholes dry up in late August. Testosterone Testosterone is the primary male sex hormone and androgen in males . In humans, testosterone plays a key role in the development of male reproductive tissues such as testicles and prostate , as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and
4141-756: The International Union for Conservation of Nature (IUCN). One of the biggest threats to elephant populations is the ivory trade , as the animals are poached for their ivory tusks. Other threats to wild elephants include habitat destruction and conflicts with local people. Elephants are used as working animals in Asia. In the past, they were used in war; today, they are often controversially put on display in zoos, or employed for entertainment in circuses . Elephants have an iconic status in human culture and have been widely featured in art, folklore, religion, literature, and popular culture. The word elephant
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4242-752: The blood . The effects include: Testosterone is necessary for normal sperm development. It activates genes in Sertoli cells , which promote differentiation of spermatogonia . It regulates acute HPA ( hypothalamic–pituitary–adrenal axis ) response under dominance challenge. Androgens including testosterone enhance muscle growth. Testosterone also regulates the population of thromboxane A 2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans. Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels might decrease in
4343-405: The incisors , known as the tusks ; 12 deciduous premolars ; and 12 molars . Unlike most mammals, teeth are not replaced by new ones emerging from the jaws vertically. Instead, new teeth start at the back of the mouth and push out the old ones. The first chewing tooth on each side of the jaw falls out when the elephant is two to three years old. This is followed by four more tooth replacements at
4444-531: The largest living land animals. Three living species are currently recognised: the African bush elephant ( Loxodonta africana ), the African forest elephant ( L. cyclotis ), and the Asian elephant ( Elephas maximus ). They are the only surviving members of the family Elephantidae and the order Proboscidea ; extinct relatives include mammoths and mastodons . Distinctive features of elephants include
4545-507: The matriarch . Males (bulls) leave their family groups when they reach puberty and may live alone or with other males. Adult bulls mostly interact with family groups when looking for a mate. They enter a state of increased testosterone and aggression known as musth , which helps them gain dominance over other males as well as reproductive success. Calves are the centre of attention in their family groups and rely on their mothers for as long as three years. Elephants can live up to 70 years in
4646-423: The pleural cavity . This may allow the animal to deal with the pressure differences when its body is underwater and its trunk is breaking the surface for air. Elephants breathe mostly with the trunk but also with the mouth. They have a hindgut fermentation system, and their large and small intestines together reach 35 m (115 ft) in length. Less than half of an elephant's food intake gets digested, despite
4747-487: The temporal gland , located on both sides of the head. This organ is associated with sexual behaviour, and males secrete a fluid from it when in musth . Females have also been observed with these secretions. Elephants are herbivorous and will eat leaves, twigs, fruit, bark, grass, and roots. African elephants mostly browse , while Asian elephants mainly graze . They can eat as much as 300 kg (660 lb) of food and drink 40 L (11 US gal) of water in
4848-421: The testicles of males and, to a lesser extent, the ovaries of females . On average, in adult males, levels of testosterone are about seven to eight times as great as in adult females. As the metabolism of testosterone in males is more pronounced, the daily production is about 20 times greater in men. Females are also more sensitive to the hormone. In addition to its role as a natural hormone, testosterone
4949-432: The ventricles of the heart split towards the top, a trait also found in sirenians. When upright, the elephant's heart beats around 28 beats per minute and actually speeds up to 35 beats when it lies down. The blood vessels are thick and wide and can hold up under high blood pressure. The lungs are attached to the diaphragm , and breathing relies less on the expanding of the ribcage. Connective tissue exists in place of
5050-596: The "shovel tuskers" like Platybelodon ), choerolophodontids and stegodontids . Around 10 million years ago, the earliest members of the family Elephantidae emerged in Africa, having originated from gomphotheres. Elephantids are distinguished from earlier proboscideans by a major shift in the molar morphology to parallel lophs rather than the cusps of earlier proboscideans, allowing them to become higher-crowned (hypsodont) and more efficient in consuming grass. The Late Miocene saw major climactic changes, which resulted in
5151-528: The African Eritherium and Phosphatherium are known from the late Paleocene . The Eocene included Numidotherium , Moeritherium , and Barytherium from Africa. These animals were relatively small and, some, like Moeritherium and Barytherium were probably amphibious. Later on, genera such as Phiomia and Palaeomastodon arose; the latter likely inhabited more forested areas. Proboscidean diversification changed little during
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#17327902314685252-665: The Greek word to mean ivory , but after the time of Herodotus , it also referred to the animal. The word elephant appears in Middle English as olyfaunt ( c. 1300 ) and was borrowed from Old French oliphant (12th century). Orycteropodidae [REDACTED] Macroscelididae [REDACTED] Chrysochloridae [REDACTED] Tenrecidae [REDACTED] Procaviidae [REDACTED] Elephantidae [REDACTED] Dugongidae [REDACTED] Trichechidae [REDACTED] Elephants belong to
5353-660: The Oligocene. One notable species of this epoch was Eritreum melakeghebrekristosi of the Horn of Africa , which may have been an ancestor to several later species. early proboscideans, e.g. Moeritherium [REDACTED] Deinotheriidae [REDACTED] Mammutidae [REDACTED] Gomphotheriidae [REDACTED] Stegodontidae [REDACTED] Loxodonta [REDACTED] Palaeoloxodon [REDACTED] Mammuthus [REDACTED] Elephas [REDACTED] A major event in proboscidean evolution
5454-499: The age of usual occurrence. For postnatal effects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone . Effects before birth are divided into two categories, classified in relation to the stages of development. The first period occurs between 4 and 6 weeks of the gestation. Examples include genital virilisation such as midline fusion, phallic urethra , scrotal thinning and rugation , and phallic enlargement; although
5555-480: The ages of four to six, 9–15, 18–28, and finally in their early 40s. The final (usually sixth) set must last the elephant the rest of its life. Elephant teeth have loop-shaped dental ridges, which are more diamond-shaped in African elephants. The tusks of an elephant are modified second incisors in the upper jaw. They replace deciduous milk teeth at 6–12 months of age and keep growing at about 17 cm (7 in)
5656-642: The beginning of the Late Pleistocene . Proboscideans underwent a dramatic decline during the Late Pleistocene as part of the Late Pleistocene extinctions of most large mammals globally, with all remaining non-elephantid proboscideans (including Stegodon , mastodons , and the American gomphotheres Cuvieronius and Notiomastodon ) and Palaeoloxodon becoming extinct, with mammoths only surviving in relict populations on islands around
5757-736: The brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game. Studies have found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression. The rise in testosterone during competition predicted aggression in males, but not in females. Subjects who interacted with handguns and an experimental game showed rise in testosterone and aggression. Natural selection might have evolved males to be more sensitive to competitive and status challenge situations, and that
5858-453: The cheek teeth (molars and premolars) became longer and more specialised. The incisors developed into tusks of different shapes and sizes. Several species of proboscideans became isolated on islands and experienced insular dwarfism , some dramatically reducing in body size, such as the 1 m (3 ft 3 in) tall dwarf elephant species Palaeoloxodon falconeri . Elephants are the largest living terrestrial animals. Some species of
5959-402: The decline and extinction of many proboscidean groups. The earliest members of the modern genera of Elephantidae appeared during the latest Miocene–early Pliocene around 5 million years ago. The elephantid genera Elephas (which includes the living Asian elephant) and Mammuthus (mammoths) migrated out of Africa during the late Pliocene, around 3.6 to 3.2 million years ago. Over the course of
6060-420: The ear is considerably thinner. Elephants are typically grey, but African elephants look brown or reddish after rolling in coloured mud. Asian elephants have some patches of depigmentation, particularly on the head. Calves have brownish or reddish hair, with the head and back being particularly hairy. As elephants mature, their hair darkens and becomes sparser, but dense concentrations of hair and bristles remain on
6161-896: The effectiveness and harm of either method is similar. Testosterone treatment for reasons other than possible improvement of sexual dysfunction may not be recommended. No immediate short term effects on mood or behavior were found from the administration of supraphysiologic doses of testosterone for 10 weeks on 43 healthy men. Testosterone levels follow a circadian rhythm that peaks early each day, regardless of sexual activity. In women, correlations may exist between positive orgasm experience and testosterone levels. Studies have shown small or inconsistent correlations between testosterone levels and male orgasm experience, as well as sexual assertiveness in both sexes. Sexual arousal and masturbation in women produce small increases in testosterone concentrations. The plasma levels of various steroids significantly increase after masturbation in men and
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#17327902314686262-479: The effects of this increased level of testosterone. Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer's type, a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of
6363-525: The elephant uses its trunk as a snorkel . The trunk also acts as a sense organ. Its sense of smell may be four times greater than a bloodhound 's nose. The infraorbital nerve , which makes the trunk sensitive to touch, is thicker than both the optic and auditory nerves. Whiskers grow all along the trunk, and are particularly packed at the tip, where they contribute to its tactile sensitivity. Unlike those of many mammals, such as cats and rats, elephant whiskers do not move independently ("whisk") to sense
6464-558: The emotions and behaviour tied to paternal care decrease testosterone levels. In humans and other species that utilize allomaternal care , paternal investment in offspring is beneficial to said offspring's survival because it allows the two parents to raise multiple children simultaneously. This increases the reproductive fitness of the parents because their offspring are more likely to survive and reproduce. Paternal care increases offspring survival due to increased access to higher quality food and reduced physical and immunological threats. This
6565-402: The environment; the trunk itself must move to bring the whiskers into contact with nearby objects. Whiskers grow in rows along each side on the ventral surface of the trunk, which is thought to be essential in helping elephants balance objects there, whereas they are more evenly arranged on the dorsal surface. The number and patterns of whiskers are distinctly different between species. Damaging
6666-410: The extinct elephant genus Palaeoloxodon considerably exceeded modern elephants in size making them among the largest land mammals ever. The skeleton is made up of 326–351 bones. The vertebrae are connected by tight joints, which limit the backbone's flexibility. African elephants have 21 pairs of ribs, while Asian elephants have 19 or 20 pairs. The skull contains air cavities ( sinuses ) that reduce
6767-585: The family Elephantidae , the sole remaining family within the order Proboscidea . Their closest extant relatives are the sirenians ( dugongs and manatees ) and the hyraxes , with which they share the clade Paenungulata within the superorder Afrotheria . Elephants and sirenians are further grouped in the clade Tethytheria . Three species of living elephants are recognised; the African bush elephant ( Loxodonta africana ), forest elephant ( Loxodonta cyclotis ), and Asian elephant ( Elephas maximus ). African elephants were traditionally considered
6868-435: The female gender and reduced heterosexual interest in adulthood. Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–7 months of age. The function of this rise in humans is unknown. It has been theorized that brain masculinization
6969-435: The femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. Prenatal androgens apparently influence interests and engagement in gendered activities and have moderate effects on spatial abilities. Among women with congenital adrenal hyperplasia , a male-typical play in childhood correlated with reduced satisfaction with
7070-519: The front and hind limbs can support an elephant's weight, although 60% is borne by the front. The position of the limbs and leg bones allows an elephant to stand still for extended periods of time without tiring. Elephants are incapable of turning their manus as the ulna and radius of the front legs are secured in pronation . Elephants may also lack the pronator quadratus and pronator teres muscles or have very small ones. The circular feet of an elephant have soft tissues, or "cushion pads" beneath
7171-400: The growth of body hair . It is associated with increased aggression , sex drive , dominance , courtship display , and a wide range of behavioral characteristics. In addition, testosterone in both sexes is involved in health and well-being, where it has a significant effect on overall mood, cognition, social and sexual behavior, metabolism and energy output, the cardiovascular system, and in
7272-773: The importance of testosterone in maintaining cardiovascular health . Nevertheless, maintaining normal testosterone levels in elderly men has been shown to improve many parameters that are thought to reduce cardiovascular disease risk, such as increased lean body mass, decreased visceral fat mass, decreased total cholesterol, and improved glycemic control. High androgen levels are associated with menstrual cycle irregularities in both clinical populations and healthy women. There also can be effects in unusual hair growth, acne , weight gain, infertility, and sometimes even scalp hair loss. These effects are seen largely in women with polycystic ovary syndrome ( PCOS ). For women with PCOS, hormones like birth control pills can be used to help lessen
7373-468: The interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations. Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli. Testosterone-specific structural brain characteristic can predict aggressive behaviour in individuals. The Annual NY Academy of Sciences has found anabolic steroid use (which increases testosterone) to be higher in teenagers, and this
7474-542: The largest ear flaps. The ossicles are adapted for hearing low frequencies, being most sensitive at 1 kHz . Lacking a lacrimal apparatus (tear duct), the eye relies on the harderian gland in the orbit to keep it moist. A durable nictitating membrane shields the globe. The animal's field of vision is compromised by the location and limited mobility of the eyes. Elephants are dichromats and they can see well in dim light but not in bright light. The elongated and prehensile trunk, or proboscis , consists of both
7575-402: The largest recorded was 302 cm (9 ft 11 in) long and weighed 39 kg (86 lb). Hunting for elephant ivory in Africa and Asia has resulted in an effective selection pressure for shorter tusks and tusklessness. An elephant's skin is generally very tough, at 2.5 cm (1 in) thick on the back and parts of the head. The skin around the mouth, anus , and inside of
7676-504: The later decades of adult life. The brain is also affected by this sexual differentiation; the enzyme aromatase converts testosterone into estradiol that is responsible for masculinization of the brain in male mice. In humans, masculinization of the fetal brain appears, by observation of gender preference in patients with congenital disorders of androgen formation or androgen receptor function, to be associated with functional androgen receptors. There are some differences between
7777-698: The literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone, where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition. Testosterone deficiency is associated with an increased risk of metabolic syndrome , cardiovascular disease and mortality , which are also sequelae of chronic inflammation . Testosterone plasma concentration inversely correlates to multiple biomarkers of inflammation including CRP , interleukin 1 beta , interleukin 6 , TNF alpha and endotoxin concentration, as well as leukocyte count. As demonstrated by
7878-449: The manus or pes , which allow them to bear the animal's great mass. They appear to have a sesamoid , an extra "toe" similar in placement to a giant panda 's extra "thumb", that also helps in weight distribution. As many as five toenails can be found on both the front and hind feet. Elephants can move both forward and backward, but are incapable of trotting , jumping , or galloping . They can move on land only by walking or ambling :
7979-425: The middle with a thinner tip and supported by a thicker base. They contain numerous blood vessels called capillaries . Warm blood flows into the capillaries, releasing excess heat into the environment. This effect is increased by flapping the ears back and forth. Larger ear surfaces contain more capillaries, and more heat can be released. Of all the elephants, African bush elephants live in the hottest climates and have
8080-413: The nose and upper lip, which fuse in early fetal development. This versatile appendage contains up to 150,000 separate muscle fascicles , with no bone and little fat. These paired muscles consist of two major types: superficial (surface) and internal. The former are divided into dorsal, ventral , and lateral muscles, while the latter are divided into transverse and radiating muscles. The muscles of
8181-464: The physiology of vaginal tissue and contribute to female genital sexual arousal. Women's level of testosterone is higher when measured pre-intercourse vs. pre-cuddling, as well as post-intercourse vs. post-cuddling. There is a time lag effect when testosterone is administered, on genital arousal in women. In addition, a continuous increase in vaginal sexual arousal may result in higher genital sensations and sexual appetitive behaviors. When females have
8282-456: The prevention of osteoporosis . Insufficient levels of testosterone in men may lead to abnormalities including frailty, accumulation of adipose fat tissue within the body, anxiety and depression, sexual performance issues, and bone loss. Excessive levels of testosterone in men may be associated with hyperandrogenism , higher risk of heart failure , increased mortality in men with prostate cancer , and male pattern baldness . Testosterone
8383-486: The primate to increasingly seek out sexual experiences with females and thus creates a sexual preference for females. Some research has also indicated that if testosterone is eliminated in an adult male human or other adult male primate's system, its sexual motivation decreases, but there is no corresponding decrease in ability to engage in sexual activity (mounting, ejaculating, etc.). In accordance with sperm competition theory, testosterone levels are shown to increase as
8484-423: The process lasting a day. An elephant's bladder can store up to 18 litres of urine and its kidneys can produce more than 50 litres of urine per day. A male elephant's testes, like other Afrotheria , are internally located near the kidneys. The penis can be as long as 100 cm (39 in) with a 16 cm (6 in) wide base. It curves to an 'S' when fully erect and has an orifice shaped like
8585-573: The relationship between more general aggressive behavior, and feelings, and testosterone. About half of studies have found a relationship and about half, no relationship. Studies have found that testosterone facilitates aggression by modulating vasopressin receptors in the hypothalamus . There are two theories on the role of testosterone in aggression and competition. The first is the challenge hypothesis which states that testosterone would increase during puberty, thus facilitating reproductive and competitive behavior which would include aggression. It
8686-493: The right. Elephant trunks are capable of powerful siphoning. They can expand their nostrils by 30%, leading to a 64% greater nasal volume, and can breathe in almost 30 times faster than a human sneeze, at over 150 m/s (490 ft/s). They suck up water, which is squirted into the mouth or over the body. The trunk of an adult Asian elephant is capable of retaining 8.5 L (2.2 US gal) of water. They will also sprinkle dust or grass on themselves. When underwater,
8787-666: The risk of becoming or staying unemployed. Research has also found that heightened levels of testosterone and cortisol are associated with an increased risk of impulsive and violent criminal behavior. On the other hand, elevated testosterone in men may increase their generosity, primarily to attract a potential mate. Most studies support a link between adult criminality and testosterone. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have found testosterone to be associated with behaviors or personality traits linked with antisocial behavior and alcoholism . Many studies have been undertaken on
8888-524: The role of testosterone is far smaller than that of dihydrotestosterone . There is also development of the prostate gland and seminal vesicles . During the second trimester, androgen level is associated with sex formation. Specifically, testosterone, along with anti-Müllerian hormone (AMH) promote growth of the Wolffian duct and degeneration of the Müllerian duct respectively. This period affects
8989-401: The skin may reduce dehydration and allow for increased thermal regulation in the long term. To support the animal's weight, an elephant's limbs are positioned more vertically under the body than in most other mammals. The long bones of the limbs have cancellous bones in place of medullary cavities . This strengthens the bones while still allowing haematopoiesis (blood cell creation). Both
9090-456: The skull, which serve as protection. Because of the size of the head, the neck is relatively short to provide better support. Elephants are homeotherms and maintain their average body temperature at ~ 36 °C (97 °F), with a minimum of 35.2 °C (95.4 °F) during the cool season, and a maximum of 38.0 °C (100.4 °F) during the hot dry season. Elephant ear flaps, or pinnae , are 1–2 mm (0.039–0.079 in) thick in
9191-529: The temporary reduction of differences in behavior between the sexes. However, the testosterone changes observed do not seem to be maintained as relationships develop over time. Men who produce less testosterone are more likely to be in a relationship or married, and men who produce more testosterone are more likely to divorce. Marriage or commitment could cause a decrease in testosterone levels. Single men who have not had relationship experience have lower testosterone levels than single men with experience. It
9292-409: The testosterone levels correlate to those levels. Studies conducted in rats have indicated that their degree of sexual arousal is sensitive to reductions in testosterone. When testosterone-deprived rats were given medium levels of testosterone, their sexual behaviours (copulation, partner preference, etc.) resumed, but not when given low amounts of the same hormone. Therefore, these mammals may provide
9393-472: The tip of the tail and parts of the head and genitals. Normally, the skin of an Asian elephant is covered with more hair than its African counterpart. Their hair is thought to help them lose heat in their hot environments. Although tough, an elephant's skin is very sensitive and requires mud baths to maintain moisture and protection from burning and insect bites. After bathing, the elephant will usually use its trunk to blow dust onto its body, which dries into
9494-514: The trunk connect to a bony opening in the skull. The nasal septum consists of small elastic muscles between the nostrils, which are divided by cartilage at the base. A unique proboscis nerve – a combination of the maxillary and facial nerves – lines each side of the appendage. As a muscular hydrostat , the trunk moves through finely controlled muscle contractions, working both with and against each other. Using three basic movements: bending, twisting, and longitudinal stretching or retracting,
9595-422: The trunk has near unlimited flexibility. Objects grasped by the end of the trunk can be moved to the mouth by curving the appendage inward. The trunk can also bend at different points by creating stiffened "pseudo-joints". The tip can be moved in a way similar to the human hand. The skin is more elastic on the dorsal side of the elephant trunk than underneath; allowing the animal to stretch and coil while maintaining
9696-508: The trunk would be detrimental to an elephant's survival, although in rare cases, individuals have survived with shortened ones. One trunkless elephant has been observed to graze using its lips with its hind legs in the air and balancing on its front knees. Floppy trunk syndrome is a condition of trunk paralysis recorded in African bush elephants and involves the degeneration of the peripheral nerves and muscles. The disorder has been linked to lead poisoning. Elephants usually have 26 teeth:
9797-433: The tusk contains the pulp , and some have nerves that stretch even further. Thus, it would be difficult to remove it without harming the animal. When removed, ivory will dry up and crack if not kept cool and wet. Tusks function in digging, debarking, marking, moving objects, and fighting. Elephants are usually right- or left-tusked, similar to humans, who are typically right- or left-handed . The dominant, or "master" tusk,
9898-489: The use of testosterone for low levels due to aging is beneficial or harmful. Testosterone is included in the World Health Organization's list of essential medicines , which are the most important medications needed in a basic health system . It is available as a generic medication . It can be administered as a cream or transdermal patch that is applied to the skin, by injection into a muscle , as
9999-419: The weight of the skull while maintaining overall strength. These cavities give the inside of the skull a honeycomb -like appearance. By contrast, the lower jaw is dense. The cranium is particularly large and provides enough room for the attachment of muscles to support the entire head. The skull is built to withstand great stress, particularly when fighting or using the tusks. The brain is surrounded by arches in
10100-463: The wild. They communicate by touch, sight, smell, and sound; elephants use infrasound and seismic communication over long distances. Elephant intelligence has been compared with that of primates and cetaceans . They appear to have self-awareness , and possibly show concern for dying and dead individuals of their kind. African bush elephants and Asian elephants are listed as endangered and African forest elephants as critically endangered by
10201-670: Was the collision of Afro-Arabia with Eurasia, during the Early Miocene, around 18–19 million years ago, allowing proboscideans to disperse from their African homeland across Eurasia and later, around 16–15 million years ago into North America across the Bering Land Bridge . Proboscidean groups prominent during the Miocene include the deinotheres , along with the more advanced elephantimorphs , including mammutids (mastodons), gomphotheres , amebelodontids (which includes
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