The Hoyo Negro Fossil Site in Yucatan, Mexico

The Hoyo Negro (black hole) fossil site is a cave located near the coast of the Yucatan Peninsula in Mexico.  The cave entrance is still above water, but most of the cave has been submerged by a rising water table.  During the late Pleistocene this cave was well above sea level.  Rising sea levels following the end of the Ice Age flooded the cave, probably about 7,000 years ago.  Inside the pitch black cave, a steep cliff, nearly the length of a football field, doomed many large vertebrates.  The cave environment preserved these remains, and scuba divers discovered them in 2007.

hoyo negro

Location of Hoyo Negro Cave.

Dirk Settlement Americas 5

Diagram of the Hoyo Negro (Black Hole) Cave.

The remains were found in a giant underwater cave called Hoyo Negro.

View from inside the cave.

At least 26 large mammals, including 12 different species, fell off the cliff and died here.  (I wonder why they were wandering deep inside the cave.)  It didn’t happen very often.  The cave existed for tens of thousands of years–the total number of individual specimens amounts to an animal falling off the cliff once every thousand years or so.  Nevertheless, the composition of species provides enough information to assume the environment surrounding the cave during the late Pleistocene consisted of tropical forest, thorny scrub, and wetlands.  The extent of each of these types of environments varied over time depending upon climatic cycles.  The remains of 5 generalist species, 5 forest species, 2 scrub species, and 1 wetland species were found in the cave.  The generalist species include saber-tooth, cougar, bobcat, coyote, and human.  Fruit bats, tapir, spectacled bear, coati-mundi, and a new species of unidentified unnamed ground sloth were species that prefer (or preferred in the case of the extinct sloth) deep forest.  Collared peccaries and the extinct Shasta ground sloth inhabit (or inhabited) thorny scrub habitat.  The gompothere, an elephant-like species, lived in marshes.  The new species of ground sloth, yet to be described in the scientific literature, was related to Jefferson’s ground sloth, a species formerly found across most of North America.

Scuba divers also excavated fruit bat guano and plant macrofossils from the cave.  The guano contained seeds from species of fruit trees that still grow wild in the region.  Fruit bats deposited the seeds of nancete fruit (Byrsonima crassifolia), sapodilla (Manicara sp.), sea grape (Coccoloba sp.), and Thevetia peruviana, (a species that produced a pod edible for fruit bats but poisonous for humans).

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The Great Fruit Bat (Artibeus lituras).  Fossils of fruit bats rest inside of Hoyo Negro.  Fruit bat guano also found in the cave contains seeds of the plants that grew in the surrounding Pleistocene environment.

Nancite fruit (Byrsonima crassifolia).  Seeds from this fruit were found in bat guano deposited in the cave.  South Americans use this fruit for flavoring ice cream and carbonated beverages.


A mostly intact human skeleton was found inside the cave.  It dated to ~12, 800 Calendar years BP.

Most people are more interested in the human skeleton found inside the cave than in the paleoecological evidence that fascinates me. The girl was about 15 years old when she fell (or was tossed off) the ledge.  She was barely more than 4 feet tall, and the morphology of her skull resembles that of other American skulls that date to 9000 BP or older.  Ancient American skulls are longer and their faces are shorter than those of modern native Americans.  Dental characteristics differ as well.  This led some anthropologists to believe the original human colonizers of the Americas were later displaced by the ancestors of native Americans.   However, mitochondrial DNA extracted from this specimen’s tooth suggests she is closely related to the ancestors of native Americans.  The difference in skull morphology between paleo-Americans and modern native Americans can be explained by evolution within the population over the past 10,000 years.

The human skeleton found in Hoyo Negro Cave dates to between 12,900-12,700 calendar years BP.  The gompothere specimen found next to it dates to between 36,000-33,000 calendar years BP.  But humans did overlap in time with gompotheres in Mexico.  There is evidence of humans killing a gompothere in western Mexico over 13,000 years ago.  See:

So…why was a teenaged girl wandering around a pitch black cave?  I suppose the most likely explanation is this: she was with a group of other reckless teenagers, some carrying torches, and she happened to step a little way away from the group and fell off the ledge.  Other explanations are almost as likely.  A jealous romantic rival, a jealous sibling, or mentally ill tribe member could’ve deliberately pushed her off the ledge. Did she kill herself because her lover rejected her?  Or did a rapist throw her off, so she couldn’t tell on him?  Maybe her pagan tribe thought returning her to mother earth would improve their luck.  Maybe she died from a parasitic infection and her pagan tribe thought she would be reborn, if they returned her to mother earth.  We will never be able to solve this mystery.


Chatters, James. C; et. al.

“Late Pleistocene Human Skeleton and mtDNA from Mexico Links Paleoamerican and Modern Native Americans”

Science May 2015


One Response to “The Hoyo Negro Fossil Site in Yucatan, Mexico”

  1. New Species of Late Pleistocene Ground Sloth and Peccary Discovered on Yucatan Peninsula | GeorgiaBeforePeople Says:

    […] the region was ecologically unique.  The area around the Hoyo del Negro fossil site (See: ) was a mix of tropical forest, thorny scrub, and wetland; but further inland desert grassland […]

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