HAVANA—A 91-year-old former comrade of Cuba’s late dictator Fidel Castro recently startled Cubans when he announced government plans to breed ostriches to help feed the masses.

Comandante Guillermo García raved on Cuba’s main TV news show about the giant flightless bird, “which produces more [meat] than a cow.” The comandante, who runs some of Cuba’s cattle-breeding operations, also extolled the meat of the hutia, a giant rodent endemic to the island, as better than beef.

Pushed by the implosion of top ally Venezuelaand sanctions imposed by the Trump administration, Cuba has driven into an economic ditch. The government has tightened state rations. Residents stand in lines for hours to buy scarce basic goods such as eggs, flour and chicken.

For many Cubans, ration lines and ostrich farms recall the grim “Special Period” in the 1990s after the collapse of its benefactor, the Soviet Union. As the Communist-run island endured near famine conditions, residents devoured cats and fried “steaks” made of breaded grapefruit rind.

“We are starting to go into a new special period,” said Osmary Armas, 45, who owns a neoclassical mansion turned bed-and-breakfast that has been largely bereft of U.S. visitors in recent months. “Things are very bad.”

For years, American officials made no secret of their belief that if the U.S. turned the economic screws, the Cuban government would be forced out. But the Cuban regime has had nearly six decades of experience defying the U.S., administering scarcity and dishing out repression.

Cuba’s police state is intact. The government has scant opposition, and commands the loyalties of many.

The Trump administration has continued to turn the screws. In early June, the administration banned U.S.-based cruise ships from traveling to Cuba, affecting some 800,000 passenger bookings in the coming months. The U.S., which doesn’t allow regular tourism to Cuba, also eliminated a “people-to-people” travel permit that most Americans use to visit the island.

Those moves came after the administration put a cap on remittances from Cuban Americans, among other steps. It has even nixed an agreement with Major League Baseball allowing Cuban baseball players to join its teams.

The administration is trying to pressure Cuba into abandoning its support of Venezuela’s beleaguered President Nicolás Maduro. The U.S. says Cuban intelligence services have prevented Venezuela’s military from removing him. Cuba denies stationing soldiers or the 2,500 security agents the U.S. says Havana has in Venezuela.

Cuba continues to count on Venezuelan largess, particularly cheap oil and cash in payment for the services of more than 20,000 Cuban doctors, but the support is dwindling. Venezuela’s contribution to Cuba’s GDP fell to 8.5% in 2017 from 22% in 2013, said Carmelo Mesa Lago, professor emeritus at the University of Pittsburgh and an expert on the Cuban economy.

During the Special Period, Cuba’s economy contracted at least 35%. Now, if all Venezuelan ties are cut, the economy could shrink by 8% to 10%, said Pavel Vidal, a Cuban economist now at the Universidad Javeriana in Cali, Colombia.

As Venezuela’s economy collapsed, some of Cuba’s Communist leaders banked that a rise in U.S. tourism would make up for the shortfall.

For an instant, hopes were high. During the frothy two years after President Obama declared an end to almost six decades of Cold War enmity and visited the island, Hollywood shot a segment of “The Fate of the Furious” on the crumbling streets of Havana, French fashion house Chanel turned the city’s once elegant El Prado boulevard into a catwalk, and the Rolling Stones, whose music Cuba once banned as decadent capitalistic noise, held a huge outdoor concert.

Some Cubans who had emigrated seeking a better life came back to the island. There was hope of a future. Private restaurants opened, art galleries boomed, old residences were renovated for rental to the flood of visitors. The number of self-employed workers grew to more than 583,000 in 2017, about 13% of the workforce, from 424,300, or 9%, in 2013, according to official Cuban statistics.

“It was the only boom we’ve ever had in my 45 years of life,” said Ms. Armas.

Mr. Trump slammed the door on this new Cuba. “We were full of hope and Trump arrived and everything started to go bad,” said restaurateur Alain Rodriguez. Business is down 60% at “Waoo!,” his restaurant in Havana, since Mr. Trump’s first months in office, he said.

A few miles away, on a chicken line outside a state-run market, tensions were high. About 100 people waited in the scarce shade of a parking lot, as police kept the peace. The crowd hissed and yelled as an older man tried to break the line. He backed off.

An officer let in several people at a time to buy their ration: two packages of chicken each.

The police presence suggested the government is wary that Cuba’s faded revolutionary dream could end in a social conflagration started by a fight over chicken parts.

“They treat us like cockroaches, stepping on us,” hissed a woman on the line, referring to Cuba’s ruling establishment. She said had been waiting for about two hours. “Everything in Cuba is political, even the chicken. They have everything and we suffer.”

She whispered: “The special period is coming, and it’s coming hard.”

In 1994, during the worst days of the Special Period, frustration with food shortages boiled over. Police battled hundreds of protesters shouting “Libertad!” in a riot known as the Maleconazo. The tide turned when the late Fidel Castro appeared on the street and protesters cheered him.

Nothing like that protest had ever been seen in Communist Cuba, and nothing like it has been seen since.

Soon after, Castro allowed Cubans to leave to the U.S. Thousands took to the sea in homemade rafts and boats. Some 35,000 made it to the U.S..

Castro died in 2016, and his brother and successor Raúl Castro has retired from the presidency. But despite the transformative power of the internet, whose use has increased in Cuba, and the lack of a charismatic figure like the late dictator, regime change appears unlikely.

“No one here is going to go into the streets and go on strike, throw stones or riot,” said a 43-year-old former security guard. He was selling guava cakes from a stand in front of his house.

The view was similar from the spacious porch in a bed-and-breakfast in Havana’s Vedado district. “Nobody can fix this. But nobody can overthrow it, either,” said proprietor Margarita Alvarez, fanning herself against the heat of a June day in Havana.