Fossil Flamingo Egg Over 8,000 Years Old Discovered at 'Mammoth Central'

A fossilized flamingo egg thousands of years old has been discovered in Mexico, the country's National Institute of Anthropology and History (INAH) announced.

The rare egg was found in a state of exceptional preservation during the construction of the Felipe Ángeles International Airport, located in the central State of Mexico.

The civilian airport—the second serving the Mexico City metropolitan area—opened in March 2022. Construction at the airport, which began in 2019, had already uncovered numerous ancient animal remains at the so-called Santa Lucía paleontological site.

These remains have included now-extinct species of horses, saber-toothed tigers, ground sloths and at least 500 mammoth specimens. The latter finds have earned the site the nickname "Mammoth Central."

Mammoth Central is now considered to be the largest deposit of fossils from the Pleistocene epoch—which lasted from around 2.58 million to 11,700 years ago—in Latin America, according to INAH.

The discovery of the fossil flamingo egg, described by INAH scientists in a study published in the journal Historical Biology on July 31 adds to the richness of this remarkable paleontological site. It's the first from the flamingo family of birds (known as Phoenicopteridae) to be found in the Americas, and only the second occurrence of such a finding worldwide.

Fossilized flamingo bones have previously been found at locations in the United States, Mexico, Costa Rica, Argentina, Uruguay and Venezuela. But scientists have never before identified a fossil flamingo egg in either North or South America.

Before this finding, the only other record of fossilized flamingo eggs in the world was a clutch of five found in Spain dated between 23-15 million years ago.

Researchers said the fossil flamingo egg found at Santa Lucía likely dates back to between 12,000 and 8,000 years ago.

The egg in question measures under 4 inches in length and has a maximum width of just over 2 inches. It is elongated in shape, featuring two pointed tips and no pattern of spots on the immaculate shell.

To determine which bird produced the egg, the study authors compared its characteristics to those of various species, such as the American white pelican, Canada goose and tundra swan, among others.

This study revealed that the egg was most similar to those seen in the family Phoenicopteridae, indicating that it had been produced by a flamingo.

It was found at the site of an ancient lake known as Xaltocan, which has now disappeared. The former lake is located in the Valley of Mexico—a highlands plateau in the center of the country in which Mexico City lies. Surrounded by mountains and volcanoes, the valley used to contain five interconnected lakes.

These lakes included Xaltocan and the largest, known as Texcoco, which contained an island upon which the ancient Aztec capital of Tenochtitlán was built.

The valley was an important center for several pre-Columbian civilizations, including the Aztecs. But from the colonial period onward, the waters of the lakes were gradually drained, with only small remnants remaining today. The lake basin is now almost completely occupied by the modern city.

The discovery of the fossil flamingo egg confirms that these birds were once part of the lake landscapes in the Valley of Mexico, and shines a light on the environmental conditions in the region thousands of years

Researchers believe that Lake Xaltocan must have had a period when its waters were high in salinity and alkalinity. These are ideal conditions for flamingos to live in and consume spirulina algae, as well as other small invertebrates.

The INAH scientists plan to conduct further research on the fossil egg in order to determine its relationship with other living and extinct species of flamingo.