The Trump administration this week levied sweeping tariffs across the globe, provoking retaliation from other countries and sending the stock market tumbling. An unexpected consequence? Penguin memes.

Images of the flightless birds have waddled their way across the internet this week after President Trump imposed tariffs on Heard Island and McDonald Islands, Australian territories near Antarctica that are home to many penguins but no people.

One meme featured an altered photo of the explosive February White House meeting in which Mr. Trump and Vice President JD Vance publicly clashed with President Volodymyr Zelensky of Ukraine. Instead of a fiery confrontation with the wartime leader, however, Mr. Trump and Mr. Vance sit next to a black-and-white bird.

One person who posted the meme wrote, “Maybe it didn’t say thank you?” in a possible reference to Mr. Vance’s accusation that Mr. Zelensky had not appropriately thanked the United States for the military support Washington had provided Kyiv throughout the war.

A different meme showed a penguin teaching sea gulls to aim their waste at Teslas, an apparent nod to Mr. Trump’s billionaire adviser, Elon Musk. Yet another showed a huge gathering of penguins with a caption citing “Unprecedented protests” on Heard Island and McDonald Islands, “as the population rises up” against Mr. Trump’s imposition of across-the-board tariffs.

The UNESCO World Heritage Convention notes the islands’ “complete absence of alien plants and animals, as well as human impact.” Still, Mr. Trump included the desolate islands on his list, imposing the 10 percent base-line tariff he placed on nearly all goods imported into the United States.

The Wednesday announcement, which Mr. Trump described as America’s “Liberation Day,” sent shock waves across the world as both allies and adversaries scrambled to make sense of the new and hefty tariffs. The move has shot U.S. import duties to the highest levels in over a century.

Also slotted for new tariffs were the British Indian Ocean Territory, a collection of mostly uninhabited islands, save for U.S. and British soldiers stationed on joint military bases.

Other islands subjected to tariffs included Tokelau, a territory of New Zealand that has fewer than 2,000 inhabitants; the Norwegian islands of Svalbard, which has about 3,000 residents; and Jan Mayen, where the only humans are the military personnel who operate a weather and coastal services station.

Mr. Trump has said little about the methodology behind the new system of calculations, but each country’s new tariff rate appeared to come from a formula that takes the trade deficit America runs with a nation and divides it by the exports that country sent into the United States. The White House explained its methodology in this post, which essentially confirms that formula.

Then, because Mr. Trump said he was being “kind,” the final tariff number was cut in half.

It is not clear how the administration decided to add Heard Island and McDonald Islands to the list of tariffs. The White House did not immediately respond to request for comment.

Jenny Gross contributed reporting.