Growth, development, and parental care in the western tarsier (Tarsius bancanus) in captivity: Evidence for a “slow” life-history and nonmonogamous mating system

Abstract

I studied reproduction, prenatal and postnatal growth rates, behavioral ontogeny, and parental care in nine captive births to two wild-caught pairs of Tarsius bancanusover a 5-year period. T. bancanusinvariably gives birth to a single infant of approximately 20% maternal body mass after an extremely long gestation period. The fetal growth rate is among the slowest recorded for any mammal and the relative postnatal growth rate to physical maturity is the lowest in a sample of 26 prosimian species examined. These life-history variables, and a slow rate of reproduction, contribute to an extremely low г max in this and other species of Tarsius.The relative rate of behavioral development, especially foraging and locomotor behaviors, is extremely rapid for a specialized predator. Infants attained nutritional independence at approximately 80 days and perfected hunting skills without apparent help from either parent. Mothers were very protective of their young and kept fathers from having contact with infants through heightened agonism after birth, and thus , there was no evidence of direct paternal care. The data suggest that there is an energetic/dietary basis for slow pre- and postnatal growth rates, but an extremely large neonatal brain size enables the rapid behavioral development and neuromuscular coordination necessary for this specialized predator to attain early nutritional independence. The captive and field data also suggest that extremely restrictive conditions exist for the purported monogamous mating system of T. bancanusand that an alternative mating system is more likely.