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Black Widow Vs. Alligator Lizard: Who Wins?
What does not kill you makes you stronger, they say. But, does that saying apply to venom? For some lizards, particularly the southern alligator lizard, the venom of black widow spiders, deadly for many other small animals, certainly does not kill it. In fact, the venom doesn't appear to impact these lizards at all, allowing lizards to make a nourishing meal of dangerous spider prey.
The alligator lizard is not hesitant when facing the spider. It quickly approaches the spider, moves into the perfect position for an attack, and then pounces. The spider is quickly devoured, her venom useless against the resistant lizard. Even more surprising: a single lizard will not only eat one or two, but five spiders without any affectation.
This is what a team of researchers from the Department of Biology and the Department of Agriculture, Veterinary and Rangeland Sciences from the University of Nevada, Reno found and reported in a study called Preying dangerously: black widow spider venom resistance in sympatric lizards, published in the Royal Society Open Science and featured in articles from the New York Times and Newseek.
"There are so many plants and animals that defend themselves using compounds, whether it's a toxin, like a poison, or a venom that, for example, the spiders have and can inject into prey but can also use to defend themselves"
The paper describes the potential coevolution between predator and prey, natural adversaries, that is often mediated by toxins or other chemical compounds, just like in this case.
"There are so many plants and animals that defend themselves using compounds, whether it's a toxin, like a poison, or a venom that, for example, the spiders have and can inject into prey but can also use to defend themselves," Chris R. Feldman, associate professor of biology and the associate director of the University's Museum of Natural History, explains. Feldman wanted to understand the coevolution around chemically mediated systems and the adaptations that allow species to evolve and combat toxins.
To do this, Feldman and his collaborators investigated the effects of black widow venom on the physical performance and muscle tissue in three different lizard species after being pricked with the spider's venom. Although the reptiles were more resistant than mammals, only one species was not affected in any way, the southern alligator lizard (Elgaria multicarinata), likely demonstrating physiological and molecular adaptations.
Biology Associate Professor Chris Feldman stands in front of stacks of terrariums in the University's Museum of Natural History. The venom-immune southern alligator lizard can be seen by museum visitors in the top left terrarium. The study in depth Feldman enlisted graduate student Vicki Thill, now a biological consultant, and other collaborators to pursue this idea of lizard immunity to black widow venom – an idea he has been interested in since a graduate student in California where black widows and lizards often overlap. Thill was excited by the prospect of working on the project for her Master's thesis with Feldman.
"This project was exactly what I was looking for – it was exciting, challenging, involved my favorite animal (lizards), and there was so much room to expand the idea and make it my own," expands Thill. "Probably the biggest challenge was deciding the best way to measure the lizard's response to venom."
The researchers obtained black widow venom from a person who breeds and milks the spiders in Arizona. Thill worked with other students to develop a three-meter-long racetrack to test the sprinting speed of different species of lizard before and after being poked with the venom. The study's control lizards would receive no venom, only a poke of saline. The other lizards would either receive the amount of venom sufficient to kill one mouse or a very high dose, capable of killing five mice.
"The sprint data gave us a sense of how much the venom can slow down these lizards, how much it might impact them ecologically. This was a 'real world' measure of resistance. For example, if the lizard gets bitten in the leg by a spider in the wild, and the venom impairs its ability to run or escape in nature," Feldman said.
From this initial test, they found out that two lizard species were resistant to black widow spider venom, the southern alligator lizard and the western fence lizard (often known as "blue-bellied lizards" in the reno area). The other species in the study responded poorly to the venom. They could not run very well after 24 hours and even after 48 hours were still impaired.
The researchers then took muscle tissue samples to see how much cellular damage the lizards experienced at the venom injection sites. Although the two seemingly immune lizards "did perform really well even after injection with venom, the western fence lizard had some muscle fiber damage associated with the venom," explains Thill. The southern alligator lizard showed minimal, if any, tissue damage and immune response, according to the paper.
Many questions yet to answerThe study demonstrates that some lizards have special adaptations that allow them to eat dangerous black widow spiders. The fact that at least one species was unharmed has opened the door to continued research to better understand the coevolution between these animals.
With the publications of this initial research, there are many more questions to be answered: What is the actual mechanism or mechanisms by which the lizards overcome the venom? Is it really coevolution? Are other species as resistant? Are there places where these lizards interact intimately with black widows and have higher resistance and places where they do not interact so the lizards aren't very resistant? How are the spiders responding? Are they able to produce more toxic venom when they have to deal with these lizards versus places where they don't?
The researchers hope to conduct similar studies with southern alligator lizards from other locations and with other lizard species to see if the traits vary from place to place, if venom resistance depends on ecological interaction, and if there are "other lizard predator and arachnid prey pairs that could yield information about antagonistic relationships," adds Thill. This is just the beginning.
This story was produced in collaboration with the Hitchcock Project for Visualizing Science at the Reynolds School of Journalism and was written by journalist and graduate student Vanesa de la Cruz Pavas.
Video footage was shot by Martin Szillat, Nick Gapp and Jennifer Kent and was edited by Martin Szillat.
New Species Of 'unusually Large' Alligator-like Lizard Discovered In Treetops Of Mexico
A new species of an "unusually large" alligator-like lizard has been discovered in the treetops of southern Mexico, after scientists spent years searching for the elusive reptile.
A study published in the journal PLOS One last week revealed that the dogged quest to find the scaly critter, dubbed the Coapilla arboreal alligator lizard — or Abronia cunemica — spanned five separate expeditions between 2015 and 2022, as Miami Herald first reported.
The tree-dwelling creatures first appeared on the scientists' radar in 2014, when a handful of "intriguing" photographs taken in the vicinity of the town of Coapilla, Chiapas state, emerged.
What followed was a search of "extraordinary difficulty" involving teams of researchers who spent a total of over 350 hours scouring the ground and scaling the branches and canopies of some 20 trees, according to the publication.
Five Coapilla arboreal alligator lizards discovered by scientists in southern Mexico are pictured. Emmanuel Javier-Vázquez/PLOS OneThe scientists' hard work ultimately paid off, resulting in the discovery of five individuals of the Coapilla lizard. A closer study of the creatures revealed that it was a previously unknown species.
Coapilla arboreal alligator lizards can reach 9.8 inches in length. They have yellow-brown scaly bodies covered in darker brown patches, but as seen in photos published in the study, their coloration may vary.
The lizards' eyes are pale yellow with dark specks. One of the specimens documented in the study had a broken tail.
The lizard were found between 11 and 64 feet up the trees, according to the research. They were most often seen in the morning and afternoon — and two of the creatures were females that "appeared to be pregnant."
The alligator-like lizards were discovered living in the canopies of trees in the town of Coapilla. Adam G. Clause/PLOS OneScientists also spotted a pair of lizards "in a courtship bite-hold on the forest floor. When they captured the male, he stopped biting the female, but then "re-initiated a more persistent bite hold on her head and neck" later in the day.
The new species was christened "cunemica" after Cuñemo, the "indigenous Zoque language" name for the town of Coapilla where the lizards were observed.
Alligator lizards are only found in Central America's humid highland forests. Adam G. Clause/Natural Earth/PLOS OneScientists said they were "intentionally" vague about the exact location of their discovery in a bid to protect the species.
Alligator lizards are only found in Central America's humid highland forests. Most of the species in that group are "mysterious" and rarely seen because of their "cryptic behavior" and limited distribution area.
What To Know About Northern Alligator Lizards
The northern alligator lizard is a small lizard found in the northwestern United States. They have a lot of similarities to their southern counterpart, but they tend to stay in the wooded areas of central California up through British Columbia and can be found as far east as Montana.
These small lizards are most active during the daytime, and you can often see them moving around on the ground or scurrying under bushes. They don't bask in the sun like other lizards, but they enjoy sunny spots with coverage. You can find them around grassy, brushy, or rocky openings. They typically hang out in forested areas. But they're also found around people's homes. They tend to spend time near rock piles and other outdoor debris.
There's much to know about the northern alligator lizards, including where they tend to live, what they eat, and if they make good pets.
The northern alligator lizard has a flat, wedge-shaped head. The body is about as wide as its head, and its legs are small and thin. One notable trait is the distinct lateral fold that runs along their lower sides. The line goes from the corner of the mouth to the tail.
The northern alligator lizard has an olive-brown body with dark spotty bands. It prefers cooler, damp habitats, rather than the high-heat areas enjoyed by its southern counterparts.
Northern alligator lizards are shy and difficult to spot in nature. They usually come out in the spring to mate and then retreat to their homes in the fall to prepare for winter. They typically go into burrow pits and hillsides for the winter.
The northern alligator lizard is cold tolerant and can handle being active in springtime, depending on location and weather conditions.
The northern alligator lizard is small with rough scales and a long tail. An adult alligator lizard reaches around 4 inches long from the snout to the back side, not counting its tail.
The tail can add an extra 6 inches to its length. Their underbellies are light gray, and each scale has a dark shadow around it.
Their scales are rectangular and can expand and fold. Northern alligator lizards typically shed their skin like a snake once a year.
Open forests, woodlands, and grassland are preferred habitats for Northern alligator lizards. They look for places where they can take cover and live under rocks, logs, and sometimes even trash.
The lizards can tolerate areas with low or mild development. This means you may find them near newly built construction, under rock piles near a house, or around rock retaining walls in your neighborhood.
You'll likely find these lizards in northern Idaho, western Montana, and along the Pacific coast, including:
If northern alligator lizards are in captivity, they need a semi-moist terrarium with places to hide. They also need plenty of space to climb. Keep a terrarium for them, and give them access to a water bowl they can get in and out of. You can fill your terrarium with moss and plants or branches, whatever you'd like to give them to move around on.
Northern alligator lizards are fascinating creatures. They're tolerant of many types of climates and habitats. This helps them survive in cities and wooded areas.
Alligator lizards feed on various invertebrate species, like ground beetles, grasshoppers, or crickets. They can also sometimes feed on small mammals and birds. In some cases, they may eat other small lizard species. Some northern alligator lizards also eat spiders, caterpillars, moths, snails, and baby mice.
The northern alligator has a long body and triangular head. When they move, they wiggle their body in an almost snake-like manner. When you first see one, you may assume the lizard is a snake. They are very skittish and are more likely to run away from you than stand their ground and bite.
Another interesting fact about the alligator lizard is that they can live up to 15 years. They also have defense mechanisms that help elongate their lives. Detaching their tails is one of the most common defense mechanisms. However, regrowing their tail takes longer and can impact their reproductive fitness and overall survival.
Common predators of the northern alligator lizard include hawks, owls, mammals, and other larger reptiles they cross paths with in their habitat. Destruction of habitat by new development can also endanger alligator lizards.
In general, alligator lizards do not make great pets. You may see these lizards in suburban areas, but that doesn't mean they should be kept as household pets. Unless you specifically rehabilitate a northern alligator lizard, a life in captivity can shorten its 15-year lifespan.
Alligator lizards are also likely to bite when they feel threatened, and keeping them in captivity can heighten that.
Though alligator lizards are not endangered, keeping them as pets is still not recommended. They have a large population and tolerance for many habitats but are not domesticated animals.
When deciding on a reptile to bring home, make sure you do your research. Tropical reptiles and small mammals are often traded in the illegal pet trade and don't do well in a home setting. If you buy a northern alligator lizard online and decide you don't want it anymore, you cannot just release it back into the wild.
The illegal pet trade is a threat to the northern alligator lizard. In some countries, they are protected under the law.
Alligator lizards are unique reptiles that are best left in the wild and appreciated when you get the chance. Other reptiles make better pets, including certain species of turtles, other lizards, and snakes.
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