Curio Cabinet

A zebra might not be able to change its stripes, but a cow can—with a little help, anyway. A group of Japanese scientists have been awarded the Ig Nobel Prize (awards given by the Annals of Improbable Science for unusual and imaginative research) proving that painting stripes on cows can imbue them with the same, fly-repellent powers that zebras possess.
 
Contrary to popular belief, a zebra’s stripes are not strictly for camouflage. The high-contrast, black-and-white striping does make it more difficult for predators to see a specific zebra’s outline in a herd, but it also confuses flies, preventing irritating bites. In Africa, horse flies and tsetse flies are a constant source of aggravation for the native fauna, as their painful bites can transmit fatal diseases like African horse sickness. As it turns out, this benefit can be conferred onto domesticated cows, who deal with flying pests of their own. The scientists who won the Ig Nobel’s Biology Prize proved this by painting some cows in black-and-white stripes and others in black stripes while leaving some unpainted. The cows were then left where they would be exposed to horse flies, and the cows that were painted black-and-white fared much better than the others. The black striped and unpainted cows received up to 110 bites in 30 minutes, while the zebra-striped cows only received 60 in the same time frame.
 
Flies don’t avoid stripes because they find them tacky, but because the stripes mess with the flies’ visual perception, preventing them from landing effectively. It’s a simple, low-tech solution to a problem that costs the cattle industry billions each year. Fighting back against the insects usually involves expensive pesticides, which have the additional risk of being toxic to the environment. It might not seem like much, but with millions of cattle all over the world, the losses add up. Flies sure are small to be causing such big problems.

 
[Image description: A black-and-white cow standing in tall grass.] Credit & copyright: Courtney Celley/USFWS. Media Usage Rights/License: Public Domain.

Like resin from a tree, the continents are drifting ever so slowly. It’s fitting, then, that amber is helping scientists learn more about Gondwana, a supercontinent that started to break up around 180 million years ago. Here’s a curious fact about amber: most deposits of the fossilized resin are found in the northern hemisphere. That fact has puzzled scientists for quite a while, and the lack of amber in the southern hemisphere has also been a detriment to paleontologists. That’s because a chunk of amber is almost like a time capsule containing information about the environment it was formed in. Although it resembles stone, amber isn’t a mineral at all, since it’s formed from the resin conifer trees, then hardens over time, turning into copal. Over millions of years, the concentration of essential oils in the resin dissipates, oxidizing the copal and producing amber. Everything from pollen to insects can be caught in amber, where they become known as bioinclusions. Amber bioinclusions can be extremely valuable to scientists, since they’re often lifeforms or substances that don’t fossilize well. No wonder, then, that scientists are so excited about finding insects preserved in amber for the first time in South America. Found in a quarry in a rain forest in Ecuador, the amber contains the preserved remains of several orders of insects, including beetles and ants, as well as pieces of spider webs. Moreover, the pollen and leaves contained in the amber show that the region was once home to ferns and conifers not found there today. In all, the rare amber deposit is proving to be a treasure trove of information about the supercontinent Gondwana, which was made up of South America, Africa, Australia, and several over landmasses. Maybe it’s time we got the gang back together to see what they’ve been up to.

 
[Image description: A chunk of amber with insects trapped inside.] Credit & copyright: Vassil, Wikimedia Commons. The copyright holder of this work has released it into the public domain. This applies worldwide.

These now-extinct people are currently making a big impact. According to a paper published in the Journal of Human Evolution by researchers at the University of Pannonia in Hungary, the remnants of Denisovan DNA might be responsible for granting some people immunity against tropical diseases. Denisovans were a group of hominins that emerged around 370,000 years ago, and their classification is still a matter of debate, owing to the limited amount of fossils found. What is known, however, is that genetic traces of Denisovans still remain in modern humans, much like with Neanderthals. Some of those traces are apparently responsible for immunity against certain tropical diseases, like malaria. Researchers came to this conclusion after using a computer model to reconstruct the ancient climates of three regions where Denisovan remains were found: Siberia, the Tibetan Plateau, and Laos. The results of the model were then compared to the habitats of disease carrying insects like mosquitoes and ticks as well as data regarding Denisovan DNA in people today. What they found was that the Denisovans likely lived in all types of environments and were exposed to many diseases that still plague people today. In places where those diseases are more common, more of the Denisovan genome remains. For example, people in Melanesia are more likely to carry HLA-H*02:07, a gene originating from Denisovans that is associated with immunity against some tropical diseases. By comparing extant genes and the diseases they are associated with, researchers can also track the migration of ancient Denisovans. For example, the aforementioned Melanesians only carry the genes related to tropical diseases, not Lyme disease, indicating that they’re not descended from the same Denisovans who lived in Siberia or Tibet and developed a resistance to that disease. Denisovans might be gone, but it seems they may never stop helping us out.

You can ko-a-la us crazy, but we think these are some of the most fascinating animals on the planet. They’re about to get a lot healthier, too: Australia recently approved a koala-specific vaccine to help the species fight chlamydia, a sexually-transmitted disease that around 48 percent of wild koalas are thought to have. The new vaccine reduces mortality by around 65 percent, which is especially good news since koala populations are currently in decline.
 
Koalas, like many animals native to Australia, are marsupials, meaning that they give birth to tiny, underdeveloped young which then attach themselves to a pouch and continue developing there. Many marsupials also carry their young in their pouches even after they’re fully developed, to protect them from predators and shield them from the elements. Koalas are around the size of small dogs, growing up to 33 inches long and weighing up to 33 pounds. They’re famous for their cute, teddy-bear-like appearance, but there’s a lot more to them than that.
 
Even among marsupials, koalas are oddballs. It’s thought that their name originates from the Dharug language, in which it means “no drink” or “no water.” Indeed, koalas almost never drink water directly, unless there’s a fire or particularly devastating heat wave. Instead, they get all their water from their only source of food: Eucalyptus leaves. Yes, koalas only eat one thing, and it’s poisonous. Most animals would die from consuming eucalyptus, but koalas have special liver enzymes and gut fauna that allow them to digest the toxic leaves with no issue.
 
There’s a price to pay for their unusual diet, though. First of all, eating just one thing means that koalas can’t adapt to other environments very well, so deforestation and diseases that affect eucalyptus trees inevitably devastate koala populations. Then there’s the fact that digesting poisonous leaves requires a lot of energy, which means that koalas have to conserve it in other areas. This is part of the reason that they spend up to 22 hours a day sleeping. It might also contribute to their extremely small brain size. Koalas have one of the smallest brain-to-body mass ratios in the entire animal kingdom, with their brains making up just 0.2 percent of their body mass. As if that’s not embarrassing enough, koalas’ brains are also smooth, which makes complex or out-of-the-norm tasks (such as eating eucalyptus leaves from anything other than an actual branch) difficult for them to learn. Large, complex brains take a lot of energy to maintain, and koalas simply don’t have enough to spare. Despite koalas’ declining population, Australia regards them as a national symbol, and conservationists are doing all they can to preserve their habitats and fight the climate change and deforestation that impacts them. They may be small (and sleepy) but they’ve got a lot of dedicated people in their corner.

 
[Image description: A koala sitting in a tree, grasping leaves in its paws.] Credit & copyright: Sklmsta, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.