Anteater’s Surprise Pregnancy: Virgin Birth Explained

Who’s Your Daddy?

Archie the giant anteater may have a hard time answering that question. Born to mom Armani at the LEO Zoological Center in Greenwich, Connecticut, Archie seems perfectly normal except for one small detail: Zookeepers have no idea how he came into being.

Archie, the anteater of mysterious origin, clings to his mother. Photograph courtesy LEO Zoological Conservation Center

Armani had previously given birth to a baby named Alice after a romantic rendezvous with Alf, a male anteater also at LEO. But this wasn’t an episode of Leave it to Beaver. Male anteaters are known to kill and eat their offspring, so the zoo’s staff kept Alf separate from Armani and Alice for several months. Before the anteater family was reunited, however, Armani somehow got pregnant with Archie, according to the Connecticut newspaper Greenwich Time. (Related post: “Weird Animal Courtship and Mating Rituals.”)

This pregnancy mystery immediately triggered thoughts of virgin birth, a.k.a. parthenogenesis. Animals conceived via parthenogenesis don’t actually have a father. Instead, the embryo grows and develops in the absence of fertilization. It sounds unusual—some might even say miraculous—but it’s a surprisingly common occurrence in the animal kingdom. Researchers believe that an absence of available males likely drives the phenomenon.

Although a variety of different animals have been found to reproduce via parthenogenesis, it is most common in invertebrates (such as water fleas, parasitic wasps, and bees) and certain types of vertebrates (fish, amphibians, and occasionally birds). Although the exact mechanisms of parthenogenetic reproduction can vary from species to species, all parthenogenesis produces normal, healthy offspring.

Check out the wide range of species below that have produced children without a father.

Komodo Dragon

In the mid-2000s, two Komodo dragons at the London Zoo laid viable eggs via parthenogenesis. Neither female had encountered a male during captivity, and subsequent genetic tests revealed no paternal contribution of DNA. (Also see “Virgin Birth Expected at Christmas—By Komodo Dragon.”)

New Mexico Whiptail

As its name suggests, this lizard lives throughout the desert southwest. It appears to have originated as a hybrid between two other closely related species: the little striped whiptail and the tiger whiptail. Although hybridization between these two whiptails can still produce viable New Mexico whiptails, all of the resulting offspring are female. Thus, the New Mexico whiptail reproduces solely via parthenogenesis.

Copperhead Snake

Parthenogenesis might seem like an especially good reproductive choice when no males are handy, but female copperhead snakes use parthenogenesis even when there are plenty of males nearby. A 2012 study in Biology Letters showed that 1 of 22 captured pregnant copperheads gave birth parthenogenetically—much higher than the researchers expected. Most of the observed cases of parthenogenesis have occurred in captive animals, leading researchers to wonder exactly what drives the process in the wild. (Related: “‘Virgin Birth’ Seen in Wild Snakes, Even When Males Are Available.”)

Hammerhead Shark

In 2001, a hammerhead shark gave birth at an Omaha zoo—hardly newsworthy. She didn’t have a mate in captivity, but zookeepers figured the shark had stored sperm after copulating in the wild, which is a quite common occurrence. The baby shark was killed shortly after birth by a stingray. Genetic analysis revealed that the little shark had no paternal DNA—only maternal genetic information. (Related: “‘Virgin Birth’ Record Broken by Hotel Shark.”)

Archie’s Mystery Solved?

Zookeepers at LEO believe that Archie was likely the result of embryonic diapause. Not virgin birth in the strict sense of the phrase, embryonic diapause happens when a mother puts a fertilized egg on hold in her uterus.

If environmental conditions aren’t right, the mother can prevent the fertilized egg from implanting and developing for a long period of time. Although the process has never been previously observed in an anteater, researchers have documented it in armadillos, which are closely related to anteaters. (Watch an anteater video.)

If Armani did undergo embryonic diapause, she’s in good company. A paper published last year in PLoS ONE showed that a wide variety of mammals have the potential to use embryonic diapause. Thus while it might look like Armani didn’t need a male to conceive Archie, she actually did. It’s just that zookeepers didn’t catch them in the act.

So the next time “Millionaire Matchmaker” or “The Bachelor” comes on TV, just imagine what kind of programming we could have if animals created shows based on their own reproductive strategies. “No Males Allowed,” anybody?

Carrie is a freelance science writer living in Virginia. When she's not writing about cool critters, she's spending time outside, drinking coffee, or knitting. You can visit her website at http://www.carriearnold.com
  • starspirit

    Are all these miracle births genetically tested to rule out a male, maybe some females can preserve sperm for when it is needed, maybe for years. Just because humans can’t , please don’t exclude the rest of species. Us humans can preserve eggs for decades, maybe non human females can capture and preserve sperm for years too. What do genetic tests say?

  • collins

    quite revealing

  • collins

    quite educative

  • Disturber

    Parthenogenic reproduction does not always produce healthy offspring. If the mother’s genome contains recessive abnormalities, those abnormalities will be expressed in the offspring. Depending upon the abnormality, the offspring will either not be viable, or will be born with the resulting defect which likely will put them at a disadvantage in the wild.

  • DaveC426913

    Pretty hard to be a virgin birth since she’d had sex – and an offspring – before this.

    Her caregivers would know this, so their thoughts would have been ‘how did she get pregnant so long after a first pregnancy?’.

    i.e. the whole virgin thing was retrofitted in editing to make a better story. :-/

  • DaveC426913

    (Though I think some women would love to embrace the idea. ‘It’s been a year since I had sex and had a child. Surely by now I’m a virgin again!’)

  • Steve

    Looks like the Greenwich zoo needed some new business

  • Steve

    That male anteaters are known to kill and eat their young? Eat?? How do they even do that, if they can´t open their jaws and have tube-like mouths to feed on diminutive prey? Care to elaborate?

  • Tonyrace

    Nice. So what is the deal about mermaids so surprised here. And No One is talking about it

  • dennis lange

    in parthogenesis, the offspring are female. Is this baby anteater male or female? The article didn’t say. Why don’t they do DNA testing to see if the father is Armani, the father of the previous offspring?

  • dchan

    if Archie is a male, mammalian genetics being what they are, he’d have to have been conceived via fertilized ovum. Birds that undergo parthenogenesis only hatch male offspring as a single “sex” chromosome results in a male bird. In mammals, the sire determines the gender of the offspring as both an X and Y chromosome are required and the dam can only pass along an X.

  • Sara

    I think the term “immaculate conception” might have been a better fit.

  • T.reas

    Anteaters cannot eat there young but they can kill them . There claws can sometimes save them from big cats. So killing a small baby is no problem.

  • Kristina

    lol, Steve, I was thinking the same thing.
    as well as the idea of parthenogenesis in an anteater/mammal rather than delayed implantation speaks enough about the article…

  • Bridgette

    Steve-they have claws. they probably rip them into tongue/bite size pieces.
    And if scientists could study this more, maybe we could avoid extinction. Also, it seems based off the article most of the babies are born healthy whereas most babies born of cloning have defects or die quickly. Cloning might be quicker but this method would be better in the long run, and later they could work on speeding up the process. 🙂

  • Candi

    In zoology, the term “virgin” includes a female that reproduces without copulation or fertilization by a male.

  • Kenya

    OK, there’s NO way that this could have been a true virgin birth because in order for her to have to given birth to a male baby her egg had to have been fertilized with a sperm containing a Y chromosome. Only male mammals can produce Y chromosomes, so for her to have given birth to a male offspring the pregnancy had to have been on hold since the egg had been fertilized. However, had the baby been female, it would much more believable and it would also prove that female anteaters can adapt reproductively when there is no male present. Sadly, it does not, but it would have made an awesome discovery. 🙁

  • Vanaathiel

    Well they should have known instantly it wasn’t parthenogenesis. If so, the offspring would have to female due to mammals having XY sex determination. In reptiles, parthenogenetic offspring can be male or female because they use ZW sex determination.

  • Sandy

    Sorry to say bt it can be a new idea of bussiness of the Zoo keeper. “A female cannot be a MOM without a male”…….

  • dave d

    I had heard about the delayed egg process in Marsupials, but not Placentals. “Virgin” has different meanings. [It is marvelous, but not ‘miraculous.’

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