Mexico's National Institute of Anthropology and History has excavated the 'mammoth trap' site in Tultepec, just north of Mexico City, to find bones in the 15,000 year old pit.

Mexican anthropologists say they have found two human-built pits dug 15,000 years ago to trap mammoths.

Researchers from Mexico's National Institute of Anthropology and History said the pits were found during excavations on land that was to be used as a garbage dump.

The pits filled with bones from at least 14 mammoths were found in the neighbourhood of Tultepec, just north of Mexico City. Some of the animals were apparently butchered.

The pits were about 1.7 metres deep and 25m in diameter. The institute said hunters may have chased mammoths into the traps. Remains of two other species that disappeared in the Americas - a horse and a camel - were also found.