Although their skin is preserved, their bones are generally not, as the acid in the peat dissolves the calcium phosphate of bone. Some of the bodies retain intricate details like tattoos and fingerprints. Fingerprint expert C.H. Vogelius Andersen was astonished to find that Grauballe Man's hand prints were clearer than his own. The stubble and facial features of Tollund Man are particularly well preserved.
Preserved bodies of humans and animals have been discovered in bogs in Britain, Ireland, northern Germany, the Netherlands, Denmark (both Jutland and Zealand), and southern Sweden. Records of such finds go back as far as the 18th century when the Kibbelgaarn body was discovered in the Netherlands in 1791. A 1965 German study cataloged more than 1850 bog bodies found in Northern Europe, however discrepancies found in the documentation has reduced the actual number of bog bodies to several hundred.
Until the mid-20th century, it was not readily apparent at the time of discovery whether a body has been buried in a bog for years, decades, or centuries. However modern forensic and medical technologies (such as radiocarbon dating) were developed that allowed researchers to more closely determine the age of the burial, the person's age at death, and other details. Scientists have been able to study their skin, reconstruct their appearance and even determine what their last meal was from their stomach contents. Their teeth also indicate their age at death and what type of food they ate throughout their life time. The earliest bog body, that of