The Pleistocene sites of the Sierra de Atapuerca (Burgos) have provided extensive samples of fossil remaings belonging to two past species of hominids: Homo antecessor and Homo heidelbergensis.
The remainings of the Homo antecessor have been recovered from the sites in the Sima del Elefante and Gran Dolina, in the Trinchera del Ferrocarril de Atapuerca, and their antiquity is calculated in range of age between 1,3 and 0,8 million years. The species Homo heidelbergensis has been located in the Sima de los Huesos of the karst complex located in the Cueva Mayor, and it maximum antiquity is estimated in 0,6 million years.
While most of the human evolution studies focused in learning the phylogenetic position of the different hominid species in the human evolution tree, the ample collection of hominid fossils from Atapuerca have allowed for a deeper knowledge on the biology of these two extinct "human" species. Particularly the collections of fossils obtained in the Sima de los Huesos add up to 6.500 remains from around thirty individuals, which means around 90 per cent of all the fossils of this European species worldwide.
The brain and mind complexity of the Homo heidelbergensis are reflected in their behavior and technology (Acheulean or Mode 2). Regarding their body size, we can confirm that the encephalization quotient of this species is slightly inferior to ours; nevertheless, Homo heidelbergensis already took care of their deceased and showed mental capabilities like planning and standardization. The pioneer study on the audition of the hominids from Sima de los Huesos has allowed us to demonstrate that the maximum hearing capacity was at the same frequency as in Homo sapiens. This is an indirect proof about the language capacity of this species, a human character that is extremely difficult to prove in extinct species. In the same way, the relationship between the craneal capacity of the newborn and the size of the birth canal, show that the hominids from the Sima de los Huesos probably had less difficulties at birth than the neonates of our species. The discovery of a complete pelvis in the Sima de los Huesos has been a key finding to work in this particular aspect of the biology of the Homo heidelbergensis, as well as to estimate the size and body weights of the species. The evidences of pathologies and the estimation of the ages of death and longevity of the individuals from this species will be further completed with data we will present to the audience.
Regarding the Homo antecessor it is important to analyze the evidences of canibalism obtained from the study of the fossil remains, and the meaning of this particular behavior in the human evolution.