Asexual lizards, virgin births and clones—the all‑female species of the animal kingdom

Phys · May 22, 2026 · 1024 words · By Louise Gentle

Evolutionary Biology Asexual Reproduction Genetic Diversity

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What to know about Evolutionary Biology

The article discusses various animal species that reproduce asexually through parthenogenesis, focusing on a new genetic study about the Amazon molly. It explains the biological mechanisms that allow these all-female populations to survive despite the lack of genetic diversity typically provided by sexual reproduction.

Propaganda risk 10%

Claims checked 22

Techniques found 1

Topics 3

Coverage spectrum

Coverage gap: Low Left coverage

Left0%

Center100%

Right0%

2 sources compared across this story cluster. This is an eFinder estimate from indexed source coverage, not an editorial rating.

What happened

Asexual lizards, virgin births and clones—the all‑female species of the animal kingdom Sadie Harley Scientific Editor Robert Egan Associate Editor It may sound too bizarre to be true, but the Amazon molly (Poecilia formosa), a fish that inhabits rivers,…

Why it matters

In 1932, the Amazon molly became the first known vertebrate to reproduce by cloning itself, producing all-female populations.

Common ground

A new genetic study published in Nature has given scientists insights into the longstanding mystery about how and why this happens.

Perspective signals

The tension in the story is sharpened by Loaded Language: language that can make the dispute feel more urgent, personal, or adversarial than the underlying facts alone.

Follow-up questions

What new context would change how readers understand this Evolutionary Biology story?
What evidence would most clearly confirm or weaken the claim that Other all-female parthenogenic vertebrates include the whiptail lizards, where almost a third of species are comprised solely of females?
How does this story connect Evolutionary Biology with Asexual Reproduction over the next few days?

open_in_new Read the original article: https://phys.org/news/2026-05-asexual-lizards-virgin-births-clones.html

analyticsAnalysis

10%

Propaganda Score

confidence: 95%

Low risk. This article shows minimal use of propaganda techniques.

psychologyPropaganda Techniques Detected

eFinder identified 1 propaganda technique in this article. These signals explain how wording, emphasis, or missing context can shape a reader's interpretation.

warning

Loaded Language 70% confidence

Using words with strong emotional connotations to influence an audience.

Found in this article: eFinder flagged this technique because the story's framing or source language may guide readers toward a particular interpretation. Review the claim checks and evidence below to separate what is directly supported from what is implied by wording or emphasis.

Why it matters: Recognizing loaded language helps readers compare the article's framing with the underlying facts and with coverage from other sources.

fact_checkClaims Checked

eFinder analyzed this article and checked 22 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

schedule Pending 12

check_circle Corroborated 5

info Single Source 2

help Insufficient Evidence 2

verified Verified 1

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Claim 1: “Other all-female parthenogenic vertebrates include the whiptail lizards, where almost a third of species are comprised solely of females.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

info

Claim 2: “A few countries such as the Maldives (38% female) and Moldova (54% female) diverge from this”

SINGLE SOURCE

The specific percentages for Maldives (38%) and Moldova (54%) are only mentioned in the cross-referenced article from The Conversation. Other search results for Maldives provide general geography but not demographic gender splits.

travel_explore

web search NEUTRAL — The Maldives, [c] officially the Republic of Maldives, [d] and historically known as the Maldive Islands, is an archipelagic country in South Asia, located in the Indian Ocean, near the southeastern b…
https://en.wikipedia.org/wiki/Maldives

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web search NEUTRAL — The Maldives is a nation of islands in the Indian Ocean, that spans across the equator. The country is comprised of 1192 islands that stretch along a length of 871 kilometers.
https://visitmaldives.com/

travel_explore

web search NEUTRAL — The Maldives Tourism: Tripadvisor has 682,928 reviews of The Maldives Hotels, Attractions, and Restaurants making it your best Maldives resource.
https://www.tripadvisor.com/Tourism-g293953-Maldives-Vacatio…

+ 1 more evidence source

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Claim 3: “the Brahminy blind snake, also known as the flowerpot snake... is the only other known vertebrate that breeds exclusively via parthenogenesis.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 4: “In 1932, the Amazon molly became the first known vertebrate to reproduce by cloning itself, producing all-female populations.”

CORROBORATED

Three independent sources (The Conversation, Futurity, and a specialized article on asexual lizards) confirm that the Amazon molly was identified in 1932 as the first known asexual vertebrate.

travel_explore

web search NEUTRAL — In 1932, the Amazon molly became the first known vertebrate to reproduce by cloning itself, producing all-female populations. A new genetic study has given scientists insights into the longstanding my…
https://theconversation.com/asexual-lizards-virgin-births-an…

travel_explore

web search NEUTRAL — The Amazon molly reproduces by "mating" with a male fish of a related species, but the male's DNA is not incorporated into the offspring.Ever since 1932, when scientists determined that the Amazon mol…
https://www.futurity.org/amazon-molly-fish-asexual-reproduct…

travel_explore

web search NEUTRAL — Amazon molly populations are 100% female, reproducing exclusively through a process called parthenogenesis. Gene conversion helps mitigate genetic issues typical of asexual reproduction.
https://cmio.org/regions/world/europe/859723-genetic-study-r…

+ 1 more evidence source

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Claim 5: “The snakes have three copies of each chromosome, rather than the usual two”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 6: “Kentish plover bird populations, where males care for offspring, comprise only 14% female”

CORROBORATED

The claim is reported in both The Conversation and the article 'Asexual lizards, virgin births and clones'.

travel_explore

web search NEUTRAL — Kentish plover bird populations, where males care for offspring, comprise only 14% female, and sea turtle populations, where sex is determined by temperature often exceed 75% female.
https://theconversation.com/asexual-lizards-virgin-births-an…

travel_explore

web search NEUTRAL — The Kentish Plover is mainly migratory north of 40° N, and dispersive and resident to the south, e.g., in Arabia. When inland, the Kentish Plover takes mainly insects, such as beetles and flies, as we…
https://www.linkedin.com/pulse/kentish-plover-sentinel-coast…

travel_explore

web search NEUTRAL — Longevity: 10 years. Both male and female birds have black bills and dark legs, however adults have dimorphic plumage.The Kentish Plover inhabits beaches, sandy beaches, islands and dunes, as well as …
https://viapontica.org/en/морски-дъждосвирец-charadrius-alex…

+ 1 more evidence source

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Claim 7: “Increased numbers of chromosomes have been found in many species, including salmon with four copies, and sturgeon fish with eight copies.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 8: “the Amazon molly, —a hybrid that arose through sexual reproduction between a female Atlantic molly (P. mexicana) and a male sailfin molly (P. latipinna)—has survived for over 100,000 years.”

CORROBORATED

Multiple sources, including Wikipedia and two separate articles, confirm the Amazon molly is a hybrid of P. mexicana and P. latipinna and has existed for approximately 100,000 years.

travel_explore

web search NEUTRAL — The Amazon molly didn't slowly evolve into a new species, it was the result of a 100,000-year-old accident. A long time ago, near Tampico, Mexico, a female Poecilia mexicana mated with a male Poecilia…
https://phys.org/news/2026-03-female-clonal-fish-species-fre…

travel_explore

web search NEUTRAL — The Amazon molly is a hybrid species, and its parent species are the sailfin molly (Poecilia latipinna) and the Atlantic molly...
https://en.wikipedia.org/wiki/Amazon_molly

travel_explore

web search NEUTRAL — Roughly 100,000 years ago, a female Poecilia mexicana crossed paths with a male Poecilia latipinna. In the world of biology, such hybridizations usually lead to a dead end—think of the mule or the lig…
https://www.sciencenewstoday.org/this-all-female-fish-specie…

+ 1 more evidence source

schedule

Claim 9: “they [blue-spotted salamanders] are kleptogenic. This means that they replace a portion of the mother's DNA with a portion of DNA from the male's sperm”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 10: “Some blue-spotted salamanders have reproduced asexually for several million years.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

verified

Claim 11: “The proportion of females in the human population is roughly 50%.”

VERIFIED

A UN report cited in web search results indicates the global population is approximately 49.6% female and 50.4% male, which aligns with the claim of 'roughly 50%'.

travel_explore

web search NEUTRAL — The human population grew by approximately 4.5 billion people during the 20th century, increasing from about 1.6 billion in 1900 to just over 6 billion by the year 2000.
https://en.wikipedia.org/wiki/World_population

travel_explore

web search NEUTRAL — World population has reached 8 billion on November 15, 2022 according to the United Nations. World population live counter with data sheets, graphs, maps, and census data regarding the current, histor…
https://www.worldometers.info/world-population/

travel_explore

web search NEUTRAL — The last World Population report, published by the UN in 2017 revealed that there were 7,550,262,000 people in the world at the time. An estimated 50.4 percent of the world’s population was male and 4…
https://www.news18.com/news/world/do-women-really-outnumber-…

+ 1 more evidence source

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Claim 12: “The New Mexico whiptail lizard... do not need sperm from a male to stimulate egg development.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

help

Claim 13: “the Amazon molly reproduces via a process called parthenogenesis, also known as "virgin birth," where young are produced from an unfertilized gamete.”

INSUFFICIENT EVIDENCE

No evidence was provided or found in the search results for this specific claim, although other claims discuss the fish's asexual nature.

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Claim 14: “the marbled crayfish, reproduce sexually in their native range but rapidly establish themselves in new habitats asexually, often from a single female.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 15: “Parthenogenesis is common in invertebrate animals, including ants, bees, and wasps.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 16: “the Amazon molly (Poecilia formosa), a fish that inhabits rivers, lakes, and swamps in Mexico and Texas, exists over much of its range in populations that are 100% female”

CORROBORATED

Multiple independent sources, including Wikipedia and The Conversation, confirm that the Amazon molly (Poecilia formosa) inhabits Mexico and Texas and consists of all-female populations.

travel_explore

web search NEUTRAL — The Amazon molly (Poecilia formosa) is a freshwater fish native to the warm waters of northeastern Mexico and the southern parts of the U.S. state of Texas. It reproduces through gynogenesis, and esse…
https://en.wikipedia.org/wiki/Amazon_molly

travel_explore

web search NEUTRAL — And yet, Amazon mollies (Poecilia formosa) have survived well beyond those estimations.The Amazon molly arose from a single hybrid mating between two sexual species, a female Poecilia mexicana and a m…
https://refractor.io/biology/all-female-fish-reproduces-with…

+ 1 more evidence source

schedule

Claim 17: “female snakes have two clitorises.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 18: “sea turtle populations, where sex is determined by temperature, often exceed 75% female.”

CORROBORATED

The claim that sea turtle populations often exceed 75% female due to temperature-dependent sex determination is reported in both The Conversation and the article 'Asexual lizards, virgin births and clones'.

travel_explore

web search NEUTRAL — Like most other species, male sea turtles will mate with any female sea turtle they can. However, when it comes to female sea turtles and mate selection, it's a little more complex. Sea turtles are kn…
https://phys.org/news/2020-02-monogamous-female-sea-turtles-…

travel_explore

web search NEUTRAL — Sea turtles, sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leather…
https://en.wikipedia.org/wiki/Sea_turtle

+ 1 more evidence source

info

Claim 19: “Asexual species are more likely to accumulate harmful mutations. This phenomenon, known as Muller's ratchet, predicts that clones should go extinct within 10,000 years.”

SINGLE SOURCE

The web search results provided for this claim are completely irrelevant, returning information about a German footballer (Thomas Müller) instead of the biological concept of Muller's ratchet.

travel_explore

web search NEUTRAL — Thomas Müller (German pronunciation: [ˈtoːmas ˈmʏlɐ]; [2] born 13 September 1989) is a German professional footballer who plays as a forward or attacking midfielder for Major League Soccer club Vancou…
https://en.wikipedia.org/wiki/Thomas_Müller

travel_explore

web search NEUTRAL — Apr 5, 2025 · Germany great Thomas Muller will end his 25-year association with Bayern Munich at the end of the current season. The 35-year-old has played the most games in the history of the club wit…
https://www.bbc.com/sport/football/articles/creq7rp215yo

travel_explore

web search NEUTRAL — Oct 2, 2025 · Thomas Muller became Germany's most successful player after winning the Canadian Championship with Vancouver Whitecaps, who defeated local rivals Vancouver FC 4-2 in the final. Muller ha…
https://www.foxsports.com/articles/soccer/thomas-muller-is-g…

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Claim 20: “In most species, such as humans, [gene conversion] is used to repair damaged DNA.”

INSUFFICIENT EVIDENCE

No evidence was provided or found in the search results for this claim.

schedule

Claim 21: “The Amazon molly has a type of parthenogenesis known as gynogenesis where sperm is required to stimulate development of the unfertilized egg.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 22: “it [parthenogenesis] has been found in other fish, amphibians, reptiles including the Komodo dragon, birds such as Californian condors and sharks, for example, hammerheads.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.