Whiptails are lizards in the family Teiidae and are found across the US and South and Central America. The are all active in the daytime and are terrestrial lizards, mostly eating insects. There are 150 species in the family, but we will be focusing on the genus Aspidoscelis, to which all whiptails belong.
Whiptails are very fast lizards, and you usually get a glimpse of them in the desert before they run away rapidly to take shelter under a plant or in shade. The tail is very long in all species, usually exceeding the length of the body. Whiptails are always on the ground, and do not climb trees or walls, etc. Coloration varies a lot in the group, but most of them are gray to black with either spots, stripes, or both in yellow or pale yellow. In some of them, the spots and stripes blend together a bit, creating a crosshatch-like pattern.
The name Aspidoscelis is Greek for "shield-leg", referring to a set of large rectangular scales on the legs.
Probably the most well-known whiptail is the New Mexico whiptail, which is a female-only species and is New Mexico's state reptile (only 28 states have state reptiles). It is easily identifiable because the middle stripe on its back is wiggly (see photo below).
Parthenogenesis, or why you don't need males:
Whiptails are of special interest because 13 species in the group Aspidoscelis are made up entirely of females - no males exist in these species. Females reproduce on their own without fertilization, and the offspring are genetic clones of the mother. Because of this they are often called "lesbian lizards".
Let's go into more detail about that! The term to describe this is parthenogenesis - the cloning of unfertilized eggs to make essentially identical offspring. These whiptails are also called asexual species.
How do the offspring end up with the correct number of chromosomes? Normally the gametes (eggs or sperm) would have half the number of chromosomes, so that they can combine with another gamete to get the full set. Don't whiptails only have eggs?
They do, but their gametes actually double the number of chromosomes during reproduction, so that when they split (meiosis), they still end up with the correct amount. In addition, this doubled set of chromosomes goes through crossing over (the chromosomes exchange sections), so that at least diversity is maintained. This also means that each daughter is not 100% a genetic clone, they can be a little bit different.
What's extra weird about the asexual whiptails is that they engage in simulated mating behavior between females. One lizard will mount another one and bite it, in a behavior called pseudocopulation. Doing this can actually increase their fertility, with the lizard being mounted producing larger eggs! The behavior causes some kind of hormonal influence. This type of behavior isn't known to be present in all the asexual species.
two ladies. sorry for putting gay lizard sex on your feed.1 source.
More about parthenogenesis:
There are two types of parthenogenesis: obligate and facultative.
Facultative means it doesn't occur all the time. This occurs in some lizard species like Komodo dragons, where a female can still reproduce in the absence of males. But male dragons do exist and they can reproduce sexually. This type is more common across animals.
Obligate means the species has no choice - they cannot reproduce sexually. The whiptails are all obligate parthenogens - they never reproduce sexually.
A lot of plants do parthenogenesis, but plants are weird so this isn't surprising (plants are insane).
Animal parthenogens are much rarer, but it is found more commonly in insects and invertebrates, like aphids, ants, wasps, and bees. Among vertebrates it's super-rare, and its only found in fish, amphibians, and reptiles. In fish, it can be found in some shark species and a molly species. In amphibians, there are asexual salamanders and frogs. Other reptiles include several gecko species, a threadsnake, some monitor lizards, and a few snakes.
Advantages of female only:
There are also benefits to being asexual. An individual that doesn't have to find a mate is at an advantage because a lot of energy can go into that. There are lots of mating-specific behavior that they can now do away with: no holding territories, fighting other males, any mating dances or displays. And it allows a greater chance of colonizing a new regions - only one individual has to make it there and start reproducing (we talked about this before with the flowerpot snake).
New Mexico Whiptail. check out the squiggly line in the center of its back.
source.
Where are they found?
The asexual whiptails are mainly in two geographic clusters in North America. One is in the southwestern deserts of the US and northern Mexico and one in southern Mexico, including Guatemala and Belize.
How does an asexual species evolve?
All of the asexual whiptails arose through hybridization of sexual species. That is to say, all asexual species are the result of two sexual species hybridizing. Some of the asexual species are polyploidy, having more than 2 sets of chromosomes.
Some genetics...
As you might imagine, only being able to produce genetic clones comes with some disadvanteges. The entire purpose of sex is to create genetic diversity, so that natural selection can occur - some genetic variants will do better than others. So when you throw that out the door, you are essentially stuck with the current variation you have. If changes occur to the environment (and they always will), that species will not be able to change and adapt to it.
One way whiptails have gone around this is by having very high genetic diversity at the beginning of the hybridization event that created asexuals. This means they are starting off with very high diversity, because the cross was between two different species.
But for long-term survival (millions of years), it's unknown how these species are going to fare. It makes me wonder whether we are witnessing a temporary event, a spin-off of nature where these species might not make it in the long-term.
I like pointing out a species' representation in popular culture sometimes, as in art, movies, etc. But with whiptails, I'm a little perplexed, because these lizards don't seem to be represented much of anywhere - not in ancient art, not in contemporary art, not in the popular media (with some exceptions of course). I'm confused as to why, because they are an extremely common feature in the desert landscape.
Here are the few cases where I have seen whiptails in culture:
Referring to some of the links above, I think whiptails make a good symbol for queer communities. I think it would be great to use this cool species as part of lgbtq+ symbology or art or culture.
But why aren't they more apparent in culture? Do people just not know about them? Do they have too restricted of a range (southwest only)? Horned lizards are in the same area and feature in a lot of current and ancient art, in sports teams, etc. Is it because they're so fast, you only get a glimpse of them? Are they not charismatic enough - they don't have any memorable features like gila monsters do? They aren't endangered, which is good I guess.
Lizards do feature in several Navajo tales and fables about Coyote, a trickster icon. These include specific interactions with horned lizards and Gila monsters, and sometimes just 'lizards' in general. It might also be the case that whiptails feature in other indigenous cultures but I'm just unaware of them. Just to be clear, I'm not an expert on indigenous culture or mythology, so there may be sociological aspects I just have no awareness of.
They aren't really any toys or plush of them, either. I did find this toy from Collectible Wildlife Gifts, which features figures of the lifecycle - adults, eggs, and hatching eggs. Hilariously, it includes two adult lizards, even though the species being portrayed is one of the asexual ones.
Referring to Lizards in Movies, a website dedicated to documenting lizard species in movies (part of the snake website I linked to other posts), there are ZERO cases of whiptails in film. The most common lizards are understandibly the large, showy and/or dangerous ones - iguanas, monitor lizards, gila monsters, and horned lizards (horny toads). I get that, because its usually for a horror-effect (gila monsters, monitors). Sometimes it's to indicate location - jungles have iguanas, the desert has horned lizards. And part of it is also probably which lizards can be transported well, or kept in captivity, and whiptails notoriously do not do well in captivity and are hard to catch because they're so fast and have high activity. But not even for setting up a desert scene?
Whiptails are also present in the southeast US - the 6-lined racerunner is an especially pretty one. So they aren't even restricted to just the desert.
I don't know, but for such a common animal, I'm surprised whiptails are not more popular. Well, maybe spreading information about them will help whiptails enter the cultural zeitgeist more. Tell your friends about whiptails, and hopefully Disney makes a major motion picture about them in the future.
lucky instar 
