pack rat#Packrat Midden
The analysis of the rat middens (English: pack rat midden ) of the American bush rat is the reconstruction of environmental and climate history ( palaeoecology, paleoclimatology ) the desert areas of the Southwestern U.S. and Mexico.
Nature of the bush rat
The American bush rat (English: packrats ) belong to the genus Neotoma and show a striking collector's instinct for material of all kinds, which they collect from a radius of less than 100 meters from the nest in caves or crevices: small stones, sticks, branches, parts of plants, seeds, bones, shells and the like. The ample output of urine of bush rats - their high fluid requirements they cover mainly through the consumption of succulents - permeates and envelops the diverse nesting material and crystallized into a rock-hard brown mass containing feed residues, faeces, skin debris, insects, pollen, spores, and so on and preserved. This waste heap of bush rat piles up until the rats are looking for some decades a new nest. For protection against mechanical damage, sun and moisture produced a distinct time capsules or climate archives, which may be more than 40,000 years old (as measured by the C14 method).
Archaeobotanists can determine remains of several dozen species of plants from a rat middens and thus have a snapshot of the vegetation in the vicinity of the building at the time of its use. Found remains of vertebrates and insects archaeozoologists allow conclusions on the former wildlife.
Results of the rat midden analysis
The results of the first rat midden analyzes led to a complete subversion of palaeo-environmental history of America's south west. The adoption of the distant formation of desert landscapes, which vorfanden European settlers, was no longer tenable. Specifically, it was found that the rise and decline of the Anasazi in the Chaco Canyon essential hung in the period 600-1200 AD, with the deforestation of the former forest of pine and juniper trees together.
The rat midden analysis is now a widely employed tool for reconstruction of historical environmental conditions and climate evolution by determining the "frozen" species composition. The measured data and facts are collected in a central archive of the U.S. Department of the Interior (North American Packrat Midden Database ), and they learn a broad scientific use.