For vertebrates, whether in the wild or in captivity, these “virgin births” are rare events triggered by unusual conditions. No mammals are known to reproduce this way because unlike simpler organisms, mammals rely on a process called genomic imprinting.
Asexual reproduction is not a thing among mammals. That changed when an international team of researchers managed to turn unfertilized eggs (oocytes) from female mice into actual embryos. All of them survived for a while, and one even made it to adulthood.
Animals that reproduce asexually include planarians, many annelid worms including polychaetes and some oligochaetes, turbellarians and sea stars. Many fungi and plants reproduce asexually. Some plants have specialized structures for reproduction via fragmentation, such as gemmae in liverworts.
Through the union of sperm and egg, mammals reproduce sexually. Males, once mature, produce viable sperm that can fertilize the egg (oocyte), released by mature females during a process called ovulation. The fertilized egg can develop into offspring.
The boa constrictor, monitor lizard and Komodo dragon are both capable of becoming pregnant without male fertilization, by parthenogenesis. This form of reproduction is not the preferred method and has evolutionary disadvantages for the species, as it constitutes a form of inbreeding that reduces genetic diversity.
Other creatures also engage in 'selfing' -- many plants pollinate themselves, and animals including the New Mexico whiptail, a lizard, can impregnate themselves too.
Many species of fish, like the kobudai, are known as “sequential hermaphrodites”: they can switch sex permanently at a specific point in their lives. The majority of “sequential hermaphrodites” are known as “protogynous” (Greek for “female first”): they switch from female to male.
The Komodo dragon is the largest vertebrate animal known to reproduce asexually. Measuring about 10 feet long and weighing some 300 pounds, the Komodo dragon has been studied extensively for its interesting physiology and behavior.
Do any species of mammals reproduce asexually? There are no known species of mammal that reproduce asexually in nature.
In mammals, a new life begins with the sperm successfully meeting the oocyte. Parthenogenesis, a way of generating offspring solely from unfertilized oocytes, is limited in mammals because of problems arising from genomic imprinting (1, 2).
In snakes, there is evidence of two naturally occurring modes of asexual reproduction. Obligatory parthenogenesis (OP) is found in exclusively parthenogenic species such as the Brahminy Blind Snake (Indotyphlops braminus) which have all-female populations [2].
In sharks, asexual reproduction commences via a birth mechanism dubbed 'automictic parthenogenesis'. It's a form of self-fertilisation that somehow mimics sexual reproduction.
When humans reproduce, there are two parents involved. DNA must be passed from both the mother and father to the child. Humans cannot reproduce with just one parent; humans can only reproduce sexually.
Marine flatworms, which are hermaphroditic (have both male and female reproductive organs), engage in “penis fencing” during mating. In this ritual, the worms use their phalluses to try and pierce through each other's skin to inseminate one another.
Parthenogenesis is the development of embryos from a single unfertilized egg. In nature, it occurs in aphids, fish, reptiles, scorpions, mites and some bees—but not in mammals.
Creating offspring without sperm
Females of these species, which include some wasps, crustaceans and lizards, reproduce only through parthenogenesis and are called obligate parthenogens.
Ethical considerations preclude definitive research on the subject, but it's safe to say that human DNA has become so different from that of other animals that interbreeding would likely be impossible.
Parthenogenesis in humans never produces viable embryos, though, because unfertilized eggs lack specific instructions about gene expression from the sperm. In general, our cells have two functional copies of each gene—one inherited from the mother and one from the father.
But surprisingly, there are many examples of hybrids that actually can have babies. This happens when the hybrid mates with another hybrid, or with the same species as one of its parents. For example, when lions and tigers hybridize they produce a liger.
1890s. 1896: German sexologist Magnus Hirschfeld wrote the pamphlet Sappho und Sokrates, which mentions people without any sexual desire and links them to the concept of "anesthesia sexual". 1897: German sexual reformist Emma Trosse gave the first definition of asexuality in her work Ein Weib?
All honey bees exhibit both sexual and asexual reproduction. Due to their haplo-diploid sex determination system, females are produced sexually from fertilised, diploid eggs. They receive half of their chromosomes from each parent. Males arise from unfertilised, haploid eggs.
The very rare animals that reproduce asexually — only about one in 1,000 of all living vertebrate species — are thought to be at an evolutionary disadvantage compared with their sexually reproduced counterparts.
Seahorses and their close relatives, sea dragons, are the only species in which the male gets pregnant and gives birth. Male seahorses and sea dragons get pregnant and bear young—a unique adaptation in the animal kingdom. Seahorses are members of the pipefish family.
Answer and Explanation: Yes, animals also have the third gender, like female spotted hyenas, such as external genitalia resembling male spotted hyenas. Worker bees might be considered a third gender in bees since they are sterile females that never breed unless they are given royal jelly.
Hermaphroditic animals—mostly invertebrates such as worms, bryozoans (moss animals), trematodes (flukes), snails, slugs, and barnacles—are usually parasitic, slow-moving, or permanently attached to another animal or plant.