There have been many little-known sightings of smaller, Therapod-like lizards across the American West, collectively referred to as “River Dinos” or “River Lizards.” Examples include the “Mountain Boomer” of West Texas, said to be a bipedal lizard up to 2 meters (6.5 ft) tall, with greenish or brownish skin. In 1993, an investigator named Jimmy Ward claimed to have heard tales about, “a giant lizard that walked on its hind legs and whose voice sounded like thunder.” The Colorado “River Lizards” and “Oklahoma Raptors,” previously thought by some to be Dromaeosaurs (which, unfortunately for the eyewitnesses, are now known to be feathered dinosaurs), are more commonly sighted than the Boomer. In 1993, a woman came forward to claim she had seen tall gray (or green) lizard-like creatures no less than three times in her life. Her first encounter was in May 1935, when she witnessed five of the creatures near Pagosa Springs.

There are several photographs in existence supposedly portraying living American dinosaurs. One of the best known, pictured above, shows a young man with a rifle holding what looks like the dead carcass of a baby dinosaur that he presumably shot. Another shows what looks like a Tyrannosaurus jutting out from just over a hill.

Reports like this persist because, well, it’s the Wild West with dinosaurs! Who can’t get behind that?

You just knew the real king of the beasts had to be around here somewhere, and of course he’s from Australia, where everything seems to want to kill you anyway.

The Australian Aboriginal peoples call it the Burrunjor, describing it as a bipedal giant reptile with strong legs and small, almost useless arms. Sound familiar? Throughout the 1950s, Australian cattle ranchers reported the bipedal tracks of some large creature that was attacking their livestock. One of the most dramatic sightings (which continue to this day) occurred near the McArthur River in 1957:

“Cattle began to panic. The ranchers were perplexed, especially when one of their team ran screaming into a nearby river for relative safety . . . a loud grunting and snorting noise was heard. Witnesses viewed the silhouette of a tall monster fleeing into a nearby scrub land and daybreak revealed several mutilated cattle, some half eaten.”

Titanoboa cerrejonensis was a prehistoric snake measuring up to 13 meters (42 ft), making it the largest snake known to science. Its fossil remains were found in northeastern Colombia and Jason Head of the University of Toronto says that he “just about screamed” when he saw the size of the fossils. We would, too.

So it shouldn’t come as much surprise that the Amazon has legends of giant snakes much larger than the anaconda that makes the region its home. Natives of the Amazon call it the “Yacumama” (“Mother of the Water”), “Black Boa,” “Sucuri Gigante,” or “Cobra Grande” and reports have ranged from 50 meters (164 ft) to a more realistic 18–24 meters (60–80 ft). There have been reports of anacondas that have reached lengths approaching the bottom range of Yucumama sightings, but none have been confirmed by science.

Opinion is divided as to whether or not such reports, if they are to be believed, represent cases of giant anacondas (meaning that science has yet to document the true upper limits of their size), an entirely new species of snake, or a prehistoric survival of Titanoboa or Gigantophis garstini. In 2009, a man from Northern Ireland named Mark Warner and his son Greg traveled to the region to try to capture evidence of the creature, assembling a team to carry out aerial surveys of selected locations. After 12 days in the jungle, hazardous weather conditions, hundreds of still photographs, and hours of video, the two men captured a photo of what they claimed to be a gigantic snake, about 40 meters (131 ft) long and almost 2 meters (6 ft) wide.

On September 25, 2001, a 19-year-old driving along Pennsylvania’s Route 119 reported what he described as “flags flapping in a thunderstorm” coming from above his car. When he looked up, he was astounded to see what looked like a bird with a 3–4.5 meter (10–15 ft) wingspan and a strange, elongated head flying above him. Over the next few months, two more witnesses would report seeing similar creatures in Greensville and Erie County, Pennsylvania. The reports were reminiscent of a string of sightings that took place in Texas in 1976 and 1982. In all cases, the creature described sounded remarkably similar to a Pterosaur. The sightings in Texas even occurred near to where the fossil of Quetzalcoatlus northropi, a large Pterosaur of the Late Cretaceous, was first discovered.

Interestingly, these “Pterosaur” sightings seemed to occur close to each other in waves. That suggests that people were really seeing something—but what? One obvious candidate is the frigate bird, whose grey feathers can look like leathery skin from the right distance and whose wingspan can reach up to 2.5 meters (8 ft). The frigate bird hardly ever lands except to tend its young and can soar effortlessly over long distances.

Over in Africa, the peoples of the Congo, Zambia, and a number of other regions speak of Kongamoto: “the Overturner of Boats.” It is described as featherless with smooth skin, a beak full of teeth, and a wingspan of 1–2 meters (4–7 ft). On the Gold Coast, British explorers in the 1920s heard tales of the Susabonsam, which grew to the height of a man and had thin, tenebrous wings like a bat.

One of the strangest dinosaurs to have ever lived, Therizinosaurus looks like a bizarre mixture of horse and bird, with awkward, Edward Scissorhands–like claws sticking from its forelimbs and feathery protrusions coming from its elbows. Oh, and, at least according to a missionary group from Creation Ministries International, the creature is still around as part of a lost world of living prehistoric creatures on the small islands of West New Britain in Papua New Guinea.

The Queensland tiger is a catlike, German Shepherd–sized marsupial long rumored to live in Australia’s Queensland Rainforest. Known to the local Aborigines as the Yarri, it first came to the attention of white settlers in the 1870s. There were a flurry of sightings in the 1940s and ’50s before, in 1961, Craig Black claimed to have seen a female carrying a pouched cub in Ben Lomond National Park. Three years later, a traveler named Rilla Martin took a picture supposedly depicting the beast. Martin’s picture gained instant notoriety as “the Ozenkadnook tiger photo.” The jury is still out on whether the photo is authentic, although what looks like an artificial prop supporting the creature has been identified sticking out of the bushes.