Abstract

Using data from the North American Orangutan SSP Stud Book, 293 deaths (97 Pongo pygmaeus (Bornean), 135 Pongo abelii (Sumatran), 60 P. pygmaeus x abelii hybrids) were identified in U.S. and Canadian zoos and private collections from January 1980 to March 2008. Thirty-one deaths were perinatal (10.6%), 18 neonatal (6.14%), 33 infants (11.3%), 11 juveniles (3.8%), 38 adolescents (13%), 21 subadult males (7.2%), 127 adults (43.4%) and 14 (4.8%) old adults (40–55 y). Necropsy diagnoses (n=35) or full reports (n=107) were available for 142 (48.5%).

Perinatal causes of death (COD) included placentitis, umbilical strangulation, congenital deformity, and maternal pre-eclampsia. Neonatal deaths were attributed to maternal factors, infections, low birth weight/prematurity, and one birth defect. Strongyloidiasis was the most important COD of infants, followed by pneumonia, trauma and one smoke inhalation. Juvenile deaths included strongyloidiasis, intestinal torsion, enteritis, respiratory infection, and autoimmune disease. Among adolescents, respiratory infection was the most reported COD; others included trauma, drowning, amoebic encephalitis, acute viral myocarditis, and balantidiasis.

For 83 of 163 orangutans over 15 years old (subadult males and adults/old adults of both sexes), 24 (28.9%) deaths were due to cardiovascular disease, 13 (15.7%) to respiratory infections, 12 (14.5%) to chronic renal disease, 5 (6%) to GI disease, 4 parturition-related, 4 neoplasia, 3 liver disease, 2 multifactorial or undetermined, 2 abdominal abscesses, 3 anesthetic associated with obesity, 2 stroke, 1 environmental, 1 complication of endocrine disease, and 1 osteoarthritis leading to euthanasia. Osteoarthritis and aortic atherosclerosis were incidental findings in several adults.