The primary structures of the beta-chains from pig (Suidae) and llama (Lama glama, Camelidae) hemoglobins are given. They differ from human beta-chains in the exchange of 22 and 23 amino acid residues, respectively. Some aspects of the sequences are discussed and the molecular interpretation of respiration at high altitudes is given. This interpretation is based on the exchange of the 2,3-diphosphoglycerate contact beta2His leads to Asn from man to llama: the interaction between the heterotropic allosteric effector 2,3-diphosphoglycerate and protein is diminished, which results in higher oxygen affinity of the hemoglobin of llama. Thus the placental respiration and the high-altitudes respiration have the same molecular mechanism.