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Forensic Psychology

Evidence Matters: Marcos' Menagerie and Source Confusion

What we can learn from nonexistent creatures in the American Southwest.

Key points

  • The confusion of sources and evidence is a major problem in the criminal justice system.
  • This evidentiary confusion has been problematic throughout human history.
  • Examples from early exploration can help us understand these phenomena in the criminal justice system today.
Matthew Sharps
Matthew Sharps

In our last post on The Forensic View, we began our series "Evidence Matters" with the 16th-century case of the monk Marcos de Niza, who was accused of outrageous fabrications in his accounts of what is now the southwestern United States. The problem is that, although he made mistakes, he does not appear to have fabricated much of anything. The stories of his "lies" may have derived from a misunderstanding of the language he used, and from source confusion—i.e., people of the time may have confused what he said with other persons' embellishments and outright fabrications, which were claimed to have originated with Fray Marcos.

Source confusion is a huge problem in our modern world as well. If you read something on the internet about preventing mosquito bites by eating mosquitos (to scare the remaining insects away, of course), and you incorrectly recall having heard this gem from the Surgeon General, the resulting confusion might cause major problems for you as you travel in malarial areas. The psychology of source confusion has a great deal of relevance for our modern world.

This is why Marcos de Niza's supposed tales of weird animals in what is now New Mexico have considerable relevance for us today.

Fray Marcos was supposed to have reported the presence of camels and elephants, as well as some weird beast with a single tooth so long that the poor creature had to lie down to eat, in the immediate vicinity of modern Zuni Pueblo in New Mexico. No such creatures ever existed there. So what was Fray Marcos thinking?

Well, he certainly wasn't thinking about weird animals. Although many books on the subject, scholarly and otherwise, accuse Marcos of producing this literary safari, the bizarre animals don't actually show up in his own reports. He never saw them, nor did he claim to have done so.

This weird menagerie does show up elsewhere, though, in a letter from 1539 by Spanish comptroller Rodrigo de Albornoz to Spanish treasurer Alonso de la Torre (in Flint and Flint, 2005). This source-confused zoological nightmare was not insignificant; three centuries later, some nineteenth-century American pioneers referred colloquially to "seeing the elephant," even in the absence of an actual pachyderm, as a very good reason to turn away from their western destinations and leave the American West to return to less-homicidal eastern climes.

Not that you had to be a panicked pioneer to believe in weird creatures out West. One of the reasons President Thomas Jefferson sent Lewis and Clark to explore a huge chunk of what is now the Western United States was his hope that things like extinct lions and giant ground sloths would be found alive in the western fastnesses. Yet, having spent most of my life in western landscapes, I must confess to having seen nothing more exotic than the occasional bear or mountain lion.

So what was up with the elephants, the camels, and the one-toothed creature sorely in need of dental attention?

A reasonable answer may be found in the existence of the American bison, a familiar creature today, but one that may have appeared wildly alien to early explorers. The gigantic and potentially violent bison, often referred to as a "cow" by those who had never seen a bison at all (Guengerich, 2013), may have provided a minimal if perhaps inaccurate cognitive framework for early explorers. Bison are big, very big, in a manner perhaps reminiscent (without direct local comparison) of the size of elephants. Bison are also famous for the occasional gigantic temper tantrum: I suspect bison would look even bigger if you got too close and had to flee at speed from the angry fluffy cows. Your resultant account of an animal as "big as an elephant" could be easily transformed by elastic human memory in other people into the single word "elephant."

As noted by Spanish explorers (Guengerich, 2013), bison also have a hump, a very pronounced hump. Cows do not; this is perhaps the source of the camel imagery. We should also recognize that, in view of the demonstrable phenomenon of source confusion, we human beings tend to mix narratives together; and before we know it, where there were actually bison, we have imaginary "elephants" and "camels" as we confuse the several sources of this information. Then we blame it all on Marcos de Niza, who never said a word about it. Source confusion again.

But what about the weird creature with the single tooth?

Well, based on God knows what linguistic corruption, poor Fray Marcos reported that the bison, whose hides he saw in place of the actual animal, had a single horn. Then, the Coronado expedition into the American Southwest, the direct consequence of Fray Marcos' reports, discovered a bizarre artifact—a single mammoth tusk (e.g., Hartmann, 2014). Now, nobody at the time had any idea what a mammoth was, and a mammoth tusk would not fit on any other creature, including a modern elephant.

And they only had one.

Human story-telling proclivities being what they are, before you knew it, you had a weird animal with only one tooth, a tooth so long that the thing had to lie down to eat; and if that wasn't worth an extra pint in any early Spanish-American pub, it's hard to imagine what would be.

Forensic psychologists may sometimes inadvertently ignore the truly human characteristics of witnesses, including storytellers who, in payment for another round, may take on the role of eyewitnesses. Yet these typically human characteristics are there, potentially available as sources of error in every case, ancient or modern; and these human psychological characteristics may become especially important for the interpretation of evidence when we consider the critical phenomenon of source confusion as a mediating variable.

The average criminal investigation does not involve weird animals. Yet the principles we derive from the study of such exotic concepts may be of great relevance in the more critical and immediate world of modern criminal investigation.


Flint, R., & Flint, S.C. (2005). Documents of the Coronado Expedition, 1539-1542. Albuquerque: University of New Mexico Press.

Guengerich, S.V. (2013). The Perceptions of the Bison in the Chronicles of the Spanish Northern Frontier. Journal of the Southwest, 55, pp. 251-276.

Hartmann, W.K. (2014). Searching for Golden Empires: Epic Cultural Collisions in Sixteenth- Century America. Tucson: University of Arizona Press.

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