1. Laika, the mutt who became a space pioneer

On November 3, 1957, Laika (meaning “barker” in Russian) traveled aboard the Soviet spacecraft Sputnik 2, becoming the first animal to orbit Earth and paving the way for human spaceflight. The canine cosmonaut made her historic mission just one month after the launch of the Soviet Union’s unmanned artificial satellite, Sputnik 1, which signaled the world’s entrance into the space age. A small, female mutt (or “muttnik” as she was dubbed in America), Laika was a stray before being captured and trained along with other potential space dogs; the Soviets preferred to use strays because they tended to be heartier than house-bound hounds. Although Soviet officials initially claimed Laika survived aboard Sputnik 2 for about a week before perishing, in 2002 it was revealed she died a few hours after blastoff due to overheating and stress. After circling Earth more than 2,000 times, Sputnik 2, with Laika’s remains inside, burned up upon re-entering the planet’s atmosphere in April 1958. In August 1960, Soviet space dogs Belka and Strelka became the first animals to circle Earth and survive. Less than a year later, on April 12, 1961, Soviet pilot Yuri Gagarin became the first human in space. Eight years after that, on July 20, 1969, the Americans put the first man on the moon with NASA’s Apollo 11 mission.

2. Cher Ami, the carrier pigeon who saved U.S. troops in World War I

During the war, Cher Ami (“dear friend” in French), a Black Check Cock carrier pigeon, was one of hundreds of birds used by the U.S. Army Signal Corps in France to transport important messages (placed in canisters attached to the birds) from commanders in the battlefield. In October 1918, Cher Ami, despite being badly wounded by enemy gunfire, delivered a message to American forces from U.S. Army Maj. Charles Whittlesey’s “Lost Battalion” of the 77th Infantry Division, which was trapped on the side of a hill in northeastern France during the Meuse-Argonne offensive, surrounded by enemy soldiers while being barraged by friendly fire from the Americans, who were unsure of the battalion’s location. Although the Germans shot at and hit Cher Ami after he took flight, the winged warrior nevertheless managed to return to his home coop and deliver a message from Whittlesey containing his men’s location. As a result, the Lost Battalion was saved, and Cher Ami later was awarded the Croix de Guerre by the French government. After he died in June 1919, the famous bird was preserved by a taxidermist and put on display at the Smithsonian.

3. Cairo, the dog who helped bring down Osama Bin Laden

On May 2, 2011, Cairo accompanied the team of U.S. Navy SEALs who killed al-Qaeda leader Bin Laden during a raid on his compound in Abbottabad, Pakistan. The mission ended a nearly decade-long international manhunt for the notorious mastermind behind the 9/11 terrorist attacks. Just as many details about the members of SEAL Team Six who were involved in the covert operation remain classified, specifics about Cairo are largely unknown to the public. According to various news accounts, the K9 warrior’s role was to help patrol the compound and attack any enemy fighters who might appear. Cairo is believed to be a Belgian Malinois, a breed that bears a resemblance to but is smaller in size than the German shepherd. The Malinois is prized by the U.S. military (which began using canines extensively starting with World War II) for its intelligence, speed, sharp sense of smell and strength (the dog’s powerful jaws have earned it the nickname “maligator”). Since the Bin Laden raid, Cairo’s whereabouts have remained a mystery; however, it has been reported that shortly after the mission, when President Barack Obama met with the SEALs to congratulate them, the commander in chief also asked to meet Cairo, who was waiting in a nearby room.

4. The rats and fleas that took a big bite out of Europe in the Middle Ages

In the mid-14th century, a deadly pandemic dubbed the Black Death wiped out an estimated one-third or more of Europe’s population, or some 25 million people. At the time, the cause of the Black Death was unknown, though some people believed it was a plot by Jews to kill Christians while others attributed it to such things as an earthquake or punishment from God for sin. Researchers later identified the culprit as plague, an infectious disease caused by the bacterium Yersinia pestis, which infects rats and other small rodents and is typically transmitted to humans by the bite of infected fleas. (The rat-flea disease-carrying combo was formidable. Rats are highly adaptable; skilled climbers, jumpers and swimmers; and prolific breeders, with a female rat capable of producing 12 litters of 20 rats each year. Fleas are blood-sucking parasites, and an adult female flea can consume 15 times its weight in blood on a daily basis. Additionally, while fleas are wingless, they have powerful hind legs that make them good jumpers.) The Black Death spread via trade routes from central Asia to Europe, where it arrived in the late 1340s and rapidly racked up massive death tolls and created social and economic upheaval. One result of the Black Death was that labor shortages in a number of areas due to population decline meant peasants were able to demand higher wages and increase their standard of living. Today, plague continues to exist in parts of the world, including the United States, where isolated cases have been reported in recent years.

5. The monkey who killed a monarch

In early October 1920, Greece’s King Alexander was walking through a garden when his dog got into a skirmish with a pet monkey. When the monarch tried to break up the fight, another monkey swooped in and bit him. The king’s wounds became infected, and he died on October 25, at age 27. Alexander had been crowned in June 1917, during World War I, after his father, King Constantine I, abdicated the throne. The pro-German Constantine, who advocated for Greek neutrality in the war, was pressured to give up his position by the Triple Entente (France, Great Britain and Russia). By the end of 1920, Constantine had been reinstated; however, during his second reign as king he led his nation in the Greco-Turkish War (1919-22), which Greece lost. Of the chain of events that followed Alexander’s death, Britain’s Winston Churchill later commented: “It is perhaps no exaggeration to remark that a quarter of a million persons died of this monkey’s bite.”