ABSTRACT
We present life history data on wild Sumatran orangutans gleaned from a 32-year and a 5.5-year study. Estimated age at first reproduction was 15.4 years. At 9.3 years, the average interbirth interval for this population is the longest ever recorded for any great ape population, significantly longer than that of a Bornean orangutan population. We find that age-specific mortality of Sumatran orangutans does not differ between sexes and is significantly lower than that of wild chimpanzees. We conclude that orangutan life history is the slowest among extant great apes. In accordance with their slow life history, longevity in the wild is estimated to be at least 58 years for males and at least 53 for females. We find no evidence for menopause. These data suggest that compared to the ancestral state, humans have undergone less of an increase in longevity than commonly assumed, and have experienced selection on earlier cessation of reproduction.
Subject(s)
Pongo pygmaeus/physiology , Animals , Biological Evolution , Female , Humans , Indonesia , Life Tables , Longevity/physiology , Male , Pan troglodytes/growth & development , Pongo pygmaeus/growth & development , Pregnancy , Reproduction/physiology , Sex RatioABSTRACT
A multilaboratory investigation has identified a new low-incidence antigen "VLAN' on the red cells of a blood donor. The VLAN antigen is destroyed by 2-aminoethylisothiouronium bromide treatment of the donor's red cells suggesting an association with the Kell system. Monoclonal antibody-specific immobilization of erythrocyte antigen analysis with anti-VLAN and with several mouse monoclonal antibodies directed at epitopes on the Kell glycoprotein gave positive results, indicating that the VLAN antigen is located on the Kell glycoprotein. The VLAN red blood cells have the common Kell phenotype: KEL:-1,2,-3,4,5,-6,7,-10,11,12,13,14,-17,18,19,-21,22,-23,-24. Additional serologic data indicate that the VLAN antigen is not part of any other ISBT blood group system, collection or series. A family study showed that the VLAN antigen is inherited since the red cells of two sisters and one niece of the propositus are also VLAN+. The ISBT Working Party on Terminology for Red Cell Surface Antigens has assigned VLAN to the Kell blood group system as KEL25 (number for computer listings 006025).