Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Risa Dickson-Crawford
Mud is Magnificent!
It’s everywhere from the mountains, to the riverbanks, and your own back yard; it’s mud, and it has value. What species are making the most of mud and clay in their environment, and what exactly are they using it for? Some species are utilizing mud to build nests, while others use it to protect themselves from the harmful rays of the sun. There are species who consume it to counteract toxic alkaloids in diet, and provide their bodies with essential minerals.
The first species are the black and yellow mud daubers; a type of solitary wasp that is commonly encountered in Arizona. While there are many members of the insect world which use mud to create their nests, this is species creates a nest that sometimes resembles miniature pottery. The female wasps gather mud in their mouthparts, adding saliva to the mix and then begin the process of layering it repeatedly until it is an adequate size for a larva to grow to its full size while safe inside (Weitz). These solitary wasps have been described as friendly in nature, and can be very helpful to have around if you have a problematic spider population.
What about birds using mud to construct their nests? House Martins and other members of the swallow family work with their partner to create clay nests that are typically found on the overhangs of buildings and houses. Due to the placement of these nests, many humans pose a direct threat to the birds. So, the next time you see a House Martin nest, keep in mind that it takes these birds roughly 3 weeks to build their dream home made of 1000 lumps of clay before you consider destroying it (The Dartmoor House Martin Project).
There are birds of a different feather who also rely on mud as a primary nest-building material- flamingos! Like the House Martins, flamingo pairs work together to build their nests very skillfully over a 6-week period (BioExpedition). Using their large bills to scoop mud into tall mounds (typically 12-inches high), the flamingos make certain that their eggs and chicks won’t be washed away by rising waters near the nesting sites (BioExpedition). The end result slightly resembles a cinder cone volcano, on a much smaller scale of course.
What about the other uses of mud? Several mammals wallow in mud to cool
themselves off, protect themselves from ultra-violet rays, and ward off
parasites. Take elephants and rhinos for instance, who learn to wallow in mud
very early on in life as it is a behavior passed on from adults to their young.
Thick skin or not, both species still need to be protected from the damages of
sunburn and overheating (Higgins). After a rhino wallows in mud, it waits for
the mud to dry and then rubs itself on tree bark to remove the dried mud; an act
which basically plucks parasite from their skin (Higgins). Elephants, on the
other hand, simply leave the mud where it is and allow it to provide a physical
barrier on their skin to protect from biting insects
Like their rhino and elephant counterparts, pigs have very few sweat glands which don’t provide much assistance to them in thermoregulation. Wallowing in the mud is critical for pigs to be able to cool off in high temperatures, as their high fat content works against them in keeping them well-insulated. So why not just take a dip in the water? Simply stated, water would evaporate quickly on its own, but when mixed with dirt, water evaporates much more slowly and allows pigs to stay cooler longer (Pappas). Are you appreciating mud yet?
Before I jump into mud’s other useful purposes, let’s briefly discuss the term “geophagia”. This is the act of eating the earth (including dirt, rocks, clay, mud, etc.), and there are several species that do it for a few different reasons (Wildlife TV). S o, who on earth is eating the earth and why? Apparently, over 200 species are, but we’ll just discuss a couple (Wildlife TV).
Some animals, like macaws in Peru, rely on the intake of clay to provide them with a mineral that they lack in their diet: sodium (Hirsch). Hundreds at a time, macaws flock to “clay licks” along the river banks, and collect clay for later consumption (Hirsch). Male butterflies of some species also take part in geophagia, in an act referred to as “puddling”. They frequent mud puddles in groups and drink from them for the same reasons the macaws are eating clay; this is how they get their sodium. The reproductive success of these male butterflies is thought to be enhanced by the sodium, as they pass it to the females and increase egg survival rates (Coetzer).
Aside from its mineral content, clay has a key feature that attracts certain
species to use it for detoxification purposes. With clay being negatively
charged, and toxins being positively charged, it transports them out of the body
before they reach an animal’s bloodstream (Starks and Slabach). Fruit bats in
the Amazon have been observed visiting exposed clay licks on cliff sides, just
as the macaws do (Starks and Slabach). Their diet consists mainly of unripened,
bitter fruits as well as seeds and leaves that contain toxins, and when female
bats are pregnant or nursing, they’re eating even more of these foods which
results in more trips to the clay licks (Starks and Slabach).
Speaking of pregnant females, what about us? Can we eat clay too? If the clay is harvested from a clean source, it can be safe for some humans to eat. Though the practice is more common in regions of Africa, pregnant women from all over the world (yes, even in the U.S.) consume white clay to relieve morning sickness in their first trimester (AboutUganda.com). As mentioned before, the clay binds to toxins as well as bacteria and viruses, which would be beneficial to the women and their fetuses. It is also eaten to supplement minerals like calcium, magnesium, and iron, which are beneficial to both mother and developing baby (AboutUganda.com).
If you didn’t see mud as magnificent before, maybe you do now!
14 Facts about House Martins. The Dartmoor House Martin Project. Retrieved from https://www.dartmoorhousemartins.org/information/house-martin-facts/.
A Gambian epauletted fruit bat, Epomophorus gambianus, takes off with a fig. Merlin D. Tuttle/Bat Conservation International. Retrieved from http://batweek.org/index.php/about/welcome-to-bat-week.
Baby elephant photo. iStock. Retrieved from https://www.smithsonianmag.com/science-nature/urchin-sunscreen-and-other-ways-animals-beat-burn-180959107/.
Bittel, Jason. Urchin Sunscreen and Other Ways Animals Beat the Burn. Smithsonian.com. Retrieved from https://www.smithsonianmag.com/science-nature/urchin-sunscreen-and-other-ways-animals-beat-burn-180959107/.
Bowl of Clay photo. AboutUganda.com. Retrieved from http://www.aboutuganda.com/uganda/health/eating-soil-pregnant.
Coetzer, Andre. Mud-puddling… the butterfly’s dirty little secret. Earth Touch News Network. Retrieved from https://www.earthtouchnews.com/in-the-field/backyard-wildlife/mud-puddling-the-butterflys-dirty-little-secret/.
Common House Martin Birds Nest photo. Alamy Stock Photo. Retrieved from http://www.alamy.com/stock-photo-common-house-martin-birds-nest-103515161.html.
Common House Martin Collecting Mud For Nest photo. Getty Images. Retrieved from http://www.gettyimages.com/detail/photo/common-house-martin-collecting-mud-for-nest-high-res-stock-photography/537010459.
Eating soil, Effects of eating soil during pregnancy. AboutUganda.com. Retrieved from http://www.aboutuganda.com/uganda/health/eating-soil-pregnant.
Flamingo Colony photo. Dreamstime Stock Photos. Retrieved from https://www.dreamstime.com/royalty-free-stock-photos-flamingo-phoenicopterus-ruber-nest-image26381298
Flamingo Chick photo. Dreamstime Stock Photos. Retrieved from https://www.dreamstime.com/photos-images/flamingo-nest.html
Flamingo Reproduction. BioExpedition.com. Retrieved from http://www.flamingos-world.com/flamingo-reproduction/.
Geophagia: Eat Dirt! Wildlife TV. Retrieved from https://wildlifetv.wordpress.com/category/diet-2/.
Higgins, Carolynne. Wallowing with Rhinos. Africa Geographic. Retrieved from https://africageographic.com/blog/wallowing-with-rhinos/.
Hirsch, Michele L. Why Do Hundreds of Macaws Gather at These Peruvian Clay Banks? Smithsonian.com. Retrieved from https://www.smithsonianmag.com/travel/why-do-hundreds-macaws-gather-these-peruvian-clay-banks-180955719/.
Mud Dauber Constructing Nest photo. Jerry Schappert. Retrieved from http://pestcemetery.com/mud-daubers-natures-perfect-potters/.
Mud Dauber Gathering Mud photo. Rolf Nussbaumer. Retrieved from https://rolfnussbaumer.photoshelter.com/image/I0000v4H2xRybIl4.
Muddy Rhino photo. Stan Osolinski. Getty Images. Retrieved from http://www.arkive.org/white-rhinoceros/ceratotherium-simum/image-G21988.html
Pappas, Stephanie. Why Pigs Love Mud. Live Science. Retrieved from https://www.livescience.com/13953-pigs-evolved-mud-wallowing.html.
Pigs in Mud with Waterslide photo. Julie M. Rodriguez. Retrieved from https://inhabitat.com/dutch-pigs-keep-cool-with-their-own-water-slide/pig-waterslide-2/
Starks, Phillip T.B. and Slabach, Brittany L. Would You Like a Side of Dirt with That? Scientific American. Retrieved from https://www.scientificamerican.com/article/would-you-like-side-dirt-eating-soil/.
Woman Eating White Clay photo. Adam Forrester. Retrieved from http://www.dailymail.co.uk/news/article-2542411/I-eat-pound-WHITE-DIRT-day-The-bizarre-southern-tradition-carried-women-crave-chalky-substance.html.