Patricia Yang has seen a lot of poop. In her time studying the dynamics of bodily fluids, the award-winning scientist has witnessed her share of cows dumping watery pies, rodents dropping little pellets, and elephants passing big balls of dung.
None of that would ultimately prepare her for what she was about to see.
It was 2015, and Yang had just presented on a mathematical model for bowel movements. A scientist at the conference asked if her theory worked for wombats, too. Yang had never seen wombat droppings, and when she googled for pictures, she found herself looking at some of the oddest-shaped poo she’d ever seen.
The Australian mammal’s faeces are shaped like little dark cubes, the only known prismatic poops in the world. In fact, wombats are the only animals scientists have found that can produce cubes naturally, and we had no idea how they were doing it.
Yang was immediately hooked. The mystery was an old one, but no one had done any hard investigations to find out what was really going on.
A wombat on Maria Island, Australia. (Posnov/Getty Images)
She and her lab supervisor at Georgia Tech, biomechanical engineer David Hu, decided to change that. In 2018, they finally got their hands on the intestine of a bare-nosed wombat (Vombatus ursinus).
It looked as though these cubes were forming even before the wombat pooped them out. Further CT scans on a live adult wombat confirmed this animal does not have a square-shaped anus; it’s just as round as those of other animals, so how do wombats excrete cubes?
As it turns out, it’s all in the intestine. Using two new wombat dissections and mathematical models, Yang and her colleagues have now figured out how wombats actually poo prisms.
The first thing you need to know is that the wombat intestine is unusually long, up to nine metres in length. Compared to humans, it takes these metre-long creatures many times longer to suck all the nutrition and water out of their food, sometimes up to five days.
As a result, wombat poos are nearly twice as dry as human poos, and this could be what helps them survive droughts in the Australian bush. This lengthy process probably also helps their poo form more concrete shapes.
Just by looking at the wombat intestine, you can clearly see the gradual transition from a “yellow-green slurry of digesta”, as the authors so bluntly put it, to a dry cube with “beveled edges and flat faces”.
Wombat intestines filled with poo hanging from top to bottom. (David Hu and Scott Carver)
Using a balloon to blow up certain parts of the intestine, researchers noticed varying levels of thickness and stiffness in some of the tissue and muscle.
Practically, this meant parts of the intestine’s circumference were contracting differently, in part due to different muscle thickness. The tight parts contracted quickly, pushing the poo harder, while the softer parts contracted more slowly, moulding corners.
Creating a simple model of the intestine, the authors found corners formed in less than 10 contraction cycles.
“With contractions occurring every couple of seconds over a time of five days, the faeces actually experience on the order of 100,000 contractions,” the team writes.
Enough of these contractions could plausibly form a series of cubes in the latter end of the wombat’s intestine when poo is most dried out. Dissections show cubes are formed only within the last 17 percent of the intestine. (In 2018, the team thought it was the last 8 percent).
It’s almost like baking a cake, Hu explains. The batter starts out wet and sloppy, drying out over time as it’s heated up in the oven. As it butts up against the edge of the cake tin, it begins to form corners and flat surfaces. Most of the solidifying happens right at the end.
Wombats, incidentally, squeeze out nearly 100 of these six-sided brownies every day.
Exactly why they do this is a whole other mystery. Wombats don’t have great eyesight and so they use their droppings to communicate with one another. As such, they like to poop on rocks, logs or other elevated places to make their message more visible.
The cube shape might therefore assist poo-stacking. Rounder faeces, after all, tend to roll away.
Wombat faeces in the field, stacked on rocks. (David Hu and Scott Carver)
But that’s just one idea. Another is that the six-sided structure of wombat poo allows for a greater surface area to increase the dispersal of the animal’s scent, which can convey social messages or reproductive status.
Other scientists think we’re reading too much into it. The cube-shaped poo is probably just a result of it being dehydrated in the gut, they argue. In zoos and wildlife parks, for instance, where wombats are well hydrated, wombat poo is much less defined.
There’s clearly a lot we still need to know about wombat poo, but Randy Ewoldt, the mechanical engineer who first brought the mystery to Yang and Hu’s attention five years ago, told ScienceAlert he’s impressed with their progress
“The authors demonstrate heroic efforts and a collaboration covering opposite sides of the globe,” Ewoldt said in an email.
“One wonders: who else could squeeze such interdisciplinary work into this multi-faceted contribution?”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
