Tuesday, June 18, 2013

Giant Bipedal Lizards in North America

Since the American civil war, large bipedal reptiles which closely resemble theropod dinosaurs have been sighted in the United States. Most of these sightings have happened in the western states, such as Wyoming, Colorado, and northern New Mexico.
Witnesses describe an animal that is always on its hind legs, is around 10 feet long from head to tail, and stands about 5 feet tall. It has a long, pointed snout filled with sharp teeth, and sharp claws on its hands and feet. It has large eyes. Sometimes, witnesses also report that these creatures have spines on their backs, like iguanas. Usually, they run away from humans. However, a few encounters do appear to show agression towards humans.

Although they have been sighted all over the southwest, there is one town in southern Colorado which has gained significant publicity in recent years due to sightings of these creatures. That town is Pagosa Springs, Colorado. The animals have been seen here since at least the 1930s. From 1995 to 2002, another rash of sightings occurred in Pagosa Springs. Several people described seeing creatures exactly like the ones that were previously seen in that area many decades earlier.
On 2 August 2002, an article in a Colorado newspaper discussed these sightings, and a local reptile expert was quoted as saying that the descriptions of the creatures did not appear to match those of any known reptile.

Convergent evolution

Researchers who have been studying the sightings have come up with several theories about what the strange animals are. Obviously, the animal that first comes to your mind when you hear the description is a small theropod dinosaur, such as a Velociraptor or a Troodon. Therefore, it is no wonder that many researchers believe that these animals are surviving theropod dinosaurs.
However, I have a hard time accepting this theory. You see, there is a trend in cryptozoology which me and many others as well have noticed. Darren Naish calls it the 'Prehistoric Survivor Paradigm' (PSP). The prehistoric survivor paradigm is the belief among some cryptozoologists that, if a cryptid looks just like a certain prehistoric animal, then it must be a surviving descendant of that prehistoric animal. Personally, I disagree with this assumption.
There exists a phenomenon which is familiar to most biologists known as convergent evolution.
Convergent evolution is when two or more unrelated organisms look or act very similar to each other, even though they are completely unrelated to each other. This often happens if both of the organisms live in similar habitats, or occupy a similar ecological niche. Convergent evolution is the reason why bats, birds, and bees all have wings. It is the reason why a rhinoceros somewhat resembles a Triceratops. It is also the reason why birds and mammals are both warm-blooded. There are lots and lots of other examples of convergent evolution out there, as well.

One of the most striking examples of convergent evolution is the resemblance of the recently-extinct Thylacine (Thylacinus cynocephalus) to the common Grey Wolf (Canis lupus). However, despite the obvious physical resemblence of these two predatory mammals, they are completely unrelated to each other. The wolf is a placental mammal, like cats, elephants, and humans, while the thylacine is a marsupial, like kangaroos and opossums.

Therefore, what I think is that a species of lizard has evolved to look like a small theropod dinosaur, due to convergent evolution. It has evolved erect limbs and bipedalism (more on this later). The type of lizard cannot be conclusively determined from the reports; however, I think it is probably an iguanian lizard.

In conclusion, I think that most of the sighting reports of "Velociraptors" in the U.S.A. are really just large bipedal lizards. I will be writing much more about these large bipedal North American lizards soon in other posts, including detailed analysis of some of the more notable sightings. I will also examine lizard anatomy and physiology much more closely, in order to clear up any confusion.

See you later!


  1. Great article, I agree that PSP does not need to be applied when we know that convergent evolution is possible. But I do wonder how many of such sightings are people witnessing large monitor lizards which have escaped or were released from exotic pet owners.

    1. That's a very good point. I recall reading a report of a "Velociraptor" sighting in Georgia. However, I now think that it was most likely just an escaped pet monitor lizard running on two legs. The sighting described it as being "lizard-like", and even described it sniffing the air the way monitor lizards do.

  2. I'm not keen on either hypothesis. The sporadic nature of the sighting REPORTS (always qualify your statements -- you don't know if a sighting has been made, only that a report has been made, whether first, second, or third-hand) makes me look for a rather more exotic explanation that involves some means of visitation from another time or place. It is not just theropods but pterosaurs, giant birds (both flightless and airborne), and so many other sporadically reported phenomena.

    1. You may be right. However, I'm afraid what you are describing falls outside my definition of cryptozoology.

    2. In my opinion, creatures misplaced in time and/or space are not technically cryptids. So that's the reason why I don't discuss those views on my blog. However, I still always try to have an open mind about these matters. You might just turn out to be right, after all. I mean, who knows?

  3. Agree 100%. I've always thought these 'dinosaurs' are some kind of lizard. Monitors can rear up on their hind legs and basilisks can run fast on two legs.
    I don't think the thylacine is extinct though.

    1. Yeah, I don't think the thylacine is extinct, either. However, it is 'officially' listed as extinct, so that's why I said that it was extinct.