What is hermaphrodite animals?

Question

What is hermaphrodite animals?

Answer 1

The idea of the hermaphrodite who has fully functioning male and female organs and is (theoretically) capable of self-fertilization is a myth, though a very persistent one, which has long exercised a fascination over the human mind. It provided a way of thinking about and transgressing the binary division between the sexes, and may have externalized and isolated less coherent ideas about the existence of contrary sexual characteristics in both sexes and about innate bisexuality.

Surprisingly, given the development of the male and female sexual organs from the same primitive gonad in the embryo and the possibility of errors occurring, various forms of hermaphroditism, though they do exist, are extremely rare. Like many rare conditions, however, it has had an interest for scientists inversely proportional to its frequency, because of the light such anomalies shed on the course of normal sexual development and the differentiation of the two sexes. There are many stages of development at which intersexuality can occur, from the chromosomal to the behavioural, but a hermaphrodite is usually taken to be an individual who has physically present both male and female gonadal organs and sexual characteristics, rather than someone, who, though to all intents and purposes of one s*x, is chromosomally of the other, as in some rare genetic conditions.

In most cases a child born with ambiguous genitalia will be assigned to the most likely gender, with, possibly, some surgical tidying up. This may be a satisfactory solution if only the external genitals are effected, but in many cases of such ambiguity, external organs which are closer to those of one s*x are found in conjunction with internal organs of the other. This may not become apparent until puberty, when the hormonal changes may lead to the ‘boy’ starting to menstruate, or having abdominal pains caused by obstructed menstruation, or the ‘girl's’ voice breaking and facial hair appearing. At this stage decisions may need to be taken as to whether the individual is ‘really’ of the gender of original assignment, and just needs some alien tissue removing, or whether they are ‘really’ of the opposite s*x. The powerful influence of the need to categorize human beings as definitely either male or female is very apparent, even though it may necessitate surgery and hormonal treatment of the unfortunate individual who fits neither.

The idea of hermaphroditism has been invoked to explain homosexuality. Abandoning a simple physical explanation, nineteenth-century sexologists projected a disjunction between external appearance and internal sense of self. Thus (echoing Elizabeth I's claim to have the ‘heart and stomach of a man’ within the body of a ‘weak and feeble’ woman) the homosexual or ‘invert’ was believed to have the spirit of one s*x inside the body of the other. The model constructed desire for the male as ‘feminine’ and for the female as ‘masculine’, thus preserving the notion of sexual difference.

If hermaphrodites did not exist, it would probably be necessary to invent them as a useful conceptual category.

Answer 2

A hermaphrodite is an organism having both male and female reproductive organs. In many species, hermaphroditism is a common part of the life-cycle, enabling a form of sexual reproduction in which the two sexes are not separated into distinct male and female types of individual. Hermaphroditism most commonly occurs in invertebrates, although it is also found in some fish, and to a lesser degree in other vertebrates.

Historically, the term hermaphrodite has also been used to describe ambiguous genitalia and gonadal mosaicism in individuals of gonochoristic species, especially human beings. The term comes from the name of the minor Greek god Hermaphroditus, son of Hermes and Aphrodite.

Recently, intersex has been used and preferred by many such individuals, encouraging medical professionals to use the term

Sequential hermaphrodites

Sequential hermaphrodites (dichogamy) occurs in species in which the individual is born as one s*x but can later change into the alternate s*x. This is in contrast with simultaneous hermaphrodites, in which an individual may possess fully functional male and female gonads. Sequential hermaphroditism is common in teleost fish, especially marine reef species. While some sequential hermaphrodites can change s*x multiple times, most can only change s*x once.

Sequential hermaphrodites fall into two broad categories:

Protandry: Where the organism is born as a male, and then changes s*x to a female.

Example: The Clownfish (Genus Amphiprion) are colorful reef fish found living in symbiosis with anemones. Generally one anemone contains a 'harem', consisting of a large female, a smaller reproductive male, and even smaller non-reproductive males. If the female is removed, the reproductive male will change s*x and the largest of the non-reproductive males will mature and become reproductive. It has been shown that fishing pressure can change when the switch from male to female occurs, since fishermen naturally prefer to catch the larger fish. The populations are generally changing s*x at a smaller size, due to artificial selection.

Protogyny: Where the organism starts as a female, and then changes s*x to a male.

Example: Wrasses (Family Labridae) are a group of reef fish in which protogyny is common. Wrasses also have an uncommon life history strategy, which is termed diandry (literally, two males). In these species, two male morphs exists: an initial phase male or a terminal phase male. Initial phase males do not look like males and spawn in groups with other females. They are not territorial. They are perhaps, female mimics (which is why they are found swimming in group with other females). Terminal phase males are territorial, and have a distinctively bright coloration. Individuals are born as males or females but if they are born males, they are not born as Terminal Phase males. Females and initial phase males can become terminal phase males. Usually the most dominant female or initial phase male replaces any terminal phase male, when those males die or abandon the group.

Simultaneous hermaphrodites

A simultaneous hermaphrodite (or synchronous hermaphrodite) is an adult organism that has both male and female sexual organs at the same time. Usually, self-fertilization does not occur.

Snails are perhaps the most classic of simultaneous hermaphrodite, and the most widespread of terrestrial animals possessing this sexual polymorphism. Using calcium carbonate 'arrows' as sperm carriers which are exchanged between snails by shooting them, sexual material is exchanged between both animals. In this way, snails have been poetically compared with Cupid for their sharing of shooting 'Arrows of Love'. After exchange of spermatazoa, both animals will lay fertilized eggs after a period of gestation, which then proceed to hatch after a development period. Snails typically reproduce in early spring and late autumn.

Hamlets, unlike other fish, seem quite at ease mating in front of divers, allowing observations in the wild to occur readily. They do not practice self-fertilization, but when they find a mate, the pair takes turns between which one acts as the male and which acts as the female through multiple matings, usually over the course of several nights.

Earthworms are another example of a simultaneous hermaphrodite. Although they possess ovaries and testes, they have a protective mechanism against self fertilization and can only function as a single s*x at one time. Sexual reproduction occurs when two worms meet and exchange gametes, copulating on damp nights during warm seasons. Fertilized eggs are protected by a cocoon, which is buried on or near the surface of the ground.

Banana Slugs are one more simultaneous hermaphrodite example. Mating with a partner is most desirable, as the genetic material of the offspring is varied, but if mating with a partner is not possible, self-fertilization is practised. The male sexual organ of an adult banana slug is quite large i

Answer 3

Do you mean which species are?

And, do they have to be simultaneous hermaphrodites or can they be sequential?

Lots of reef fish species are sequential hermaphrodites, but there is a killifish species that is also a simultaneous (and can self-fertilize).  

Many land snails are hermaphrodites, barnacles are, scallops, ascidians (sea squirts), corals, and sponges (but the sponges are sequential).

Answer 4

Invertebrates and some fish that have both sexes or change sexes after being born

Sequential hermaphrodites - teleost fish

Protandry - born male then change to female, clown fish, anemones

Protogyny- starts as female then changes to male

Simultaneous hermaphrodites- adult organism that has both at the same time ,  snails, earth worms, banana slugs

Pseudohermaphroditism-  hyenas have an enlarged cli-toris which is confused as a male organ.