ONE WILD WORLD — NEWSLETTER

ISSUE #043 · USELESS BUT FASCINATING · JULY 2026

The image is one of the most famous in the world. A matador flourishes a red cape; a snorting bull lowers its head and charges. The colour drives the animal mad. It doesn’t. The bull cannot see it.

Cattle are dichromats, like most mammals. They have two types of cone cells in their retinas, sensitive to blue and yellow-green, and lack the red receptor that humans use. A red muleta looks brownish or yellowish grey to them. What the bull is reacting to is not the colour but the motion — the rapid, aggressive flourish. In 2007 the American programme MythBusters put this to a live test with three flags: red, white and blue. Stationary, the bull ignored all three equally. Waved, the bull charged all three equally.

The muleta is red for a much older reason. It hides the blood.

In March 1651, at the tail end of the English Civil War, the Dutch admiral Maarten Tromp sailed to a cluster of five small islands off the coast of Cornwall called the Isles of Scilly. He was there to demand reparations from the retreating Royalist navy, which had been raiding Dutch shipping in the Channel. When the Royalists refused, Tromp formally declared war on the Isles of Scilly and the Isles of Scilly alone.

Three months later, Parliamentarian forces took the islands. The Dutch fleet, no longer under threat, sailed home. In the general relief, everybody forgot to sign a peace treaty. The state of war between the Netherlands and the Isles of Scilly quietly continued for the next three and a third centuries, unremarked by anyone in either party.

In 1985 a local Scilly historian named Roy Duncan wrote to the Dutch embassy in London to ask, on a hunch, whether the war had ever actually ended. Embassy staff searched their files and found, to some embarrassment, that it had not. Ambassador Jonkheer Rein Huydecoper travelled to the islands on 17 April 1986 and signed a peace treaty. He remarked, at the ceremony, that it must have been dreadful for the Scillonians to know the Dutch could have attacked at any moment.

Zero shots. Zero casualties. Three hundred and thirty-five years and eighteen days. Some historians argue Admiral Tromp did not actually have authority to declare war in the first place, which is perhaps why nobody noticed for so long.

Not roughly cube-shaped. Actual cubes with visibly flat faces and sharp corners, roughly two centimetres across, produced at the rate of eighty to a hundred per animal per night. The bare-nosed wombat is the only known animal in the world that does this. It uses the cubes to mark territory on the tops of rocks and logs, where they conveniently do not roll off.

The mechanism was worked out in 2018 by Patricia Yang, a mechanical engineer at the Georgia Institute of Technology, whose first response on hearing about the phenomenon was to Google it and assume it was a joke. It is not what you are picturing. The wombat’s anus is round like everyone else’s. The cubes are formed in the last eight per cent of the intestine, where the muscular wall has ridges of varying stiffness that press unevenly on the passing material and, over a series of contractions, sculpt flat faces and right-angle corners into it before it exits. Yang and her team won the 2019 Ig Nobel Prize for Physics for the work.

Not a single horned helmet has ever been recovered from a Viking Age site. Not one. Actual Viking helmets — the small handful of them that have been found, mostly in Norway and Sweden — are plain iron domes with a nasal guard and sometimes a spectacle-style eye plate. Adding horns to a battle helmet would have made it heavier, easier to grab, and useless against a downward sword stroke. No self-respecting warrior would have gone near one.

The image comes almost entirely from a single man: Carl Emil Doepler, the costume designer for the first Bayreuth production of Richard Wagner’s opera cycle Der Ring des Nibelungen in 1876. Doepler put horns on the helmet of one character — Hunding, a brutish warrior described in the libretto as being of “giants’ blood” — and wings on the helmets of the Valkyries. Nineteenth-century German nationalist illustrators, hungry for a heroic Norse iconography, generalised the horns onto every Viking in sight. By 1900 the image was in children’s books and popular histories. By 1961 it was on the helmet of the newly-founded Minnesota Vikings.

The Yale medievalist Roberta Frank published a landmark essay in 2000 titled “The Invention of the Viking Horned Helmet” that traced the whole line from Bayreuth to the present. It is a masterpiece of citation-chasing.

One caveat, because it matters. Horned helmets did exist in Scandinavia. They were ceremonial pieces made in the Bronze Age, roughly 1,500 years before the Vikings existed. Two of them, from around 900 BC, were pulled out of a Danish bog in 1942. They were never worn in battle by anyone, and certainly not by Ragnar Lothbrok.

Until 1947, less than one in ten American engagement rings contained a diamond. Diamond jewellery had been in a sales slump since the Depression, seen as a Victorian affectation and a poor use of scarce dollars. The De Beers cartel, then the world’s effective monopoly on diamond supply, had hired the Philadelphia advertising agency N.W. Ayer to solve the problem. The account fell to Frances Gerety, a 31-year-old copywriter in the women’s department, on the grounds that engagement rings were a women’s subject.

One night in 1947 she’d forgotten to prepare a pitch for the next morning’s meeting. She stayed late at her desk in an empty office, put her head down, said something between a curse and a prayer, and scribbled four words on the bottom of a photograph of a honeymooning couple. A diamond is forever. She went home. Her male colleagues in the copy department, when she showed them the line the next morning, had to ask her what it meant.

It ran in a De Beers ad in 1948. It has appeared in every De Beers engagement campaign since. Within a generation, the American diamond engagement ring went from an oddity to a near-universal expectation, and the world diamond market rose into the tens of billions of dollars a year. In April 1999, the trade magazine Advertising Age named “A Diamond Is Forever” the best advertising slogan of the twentieth century. Frances Gerety died at her home in Derby, Pennsylvania, a few weeks later, aged 83. She left no children and no spouse, and by most accounts she had never married.

Five confidently held things, five small corrections. You can drop any of them into a conversation this week and watch someone’s face do the tiny recalculation. That is the entire point of this newsletter.

Bulls / red cape: Live Science, “Why Do Bulls Charge When They See Red?” (Brooke Borel, 2011); MythBusters, Discovery Channel, 2007 season, three-flag experiment; West Texas A&M physics FAQ (Christopher Baird) on bovine dichromacy.

335 Years’ War: Wikipedia, “Three Hundred and Thirty Five Years’ War” (citing Bowley 2001 and primary embassy correspondence); Historic UK, “The 335 Year War”; War History Online, “The Three Hundred and Thirty-Five Years’ War” (2016).

Wombat cubes: P. J. Yang, A. B. Lee, M. Chan et al., “Intestines of Non-Uniform Stiffness Mold the Corners of Wombat Feces” (Soft Matter, 2021), building on the 2018 APS Division of Fluid Dynamics paper; Smithsonian Magazine coverage 2018 and 2021; Ig Nobel Prize archive (Physics, 2019).

Viking horned helmets: Roberta Frank, “The Invention of the Viking Horned Helmet” in International Scandinavian and Medieval Studies in Memory of Gerd Wolfgang Weber (2000); Wikipedia biographical entry on Carl Emil Doepler; National Museum of Denmark on the Viksø Bronze Age helmets (c. 900 BC).

A Diamond Is Forever: The Atlantic, “How an Ad Campaign Invented the Diamond Engagement Ring” (Uri Friedman, 2015); The New York Times obituary of Frances Gerety (April 1999); Wikipedia biographical entry on Mary Frances Gerety; Advertising Age slogan-of-the-century announcement, April 1999.

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