The mating system of H. liberiensis has only been observed in captive individuals. In captivity only monogamous mating has occurred. This is very unlikely in the wild, however, because the home range of a single male overlaps the home ranges of several females. Mating in captivity has been observed both on land and in water and can take place one to four times during the female's estrous period, which lasts one or two days.
Mating System: monogamous ; polygynous
Very little is known about the reproductive behavior of H. liberiensis in the wild. All of the information here is based on observations of captive animals. The breeding season is unknown in the wild but in captivity can occur at any time of the year. The breeding interval is between 7 and 9 months. The gestation period lasts as little as 184 days or as long as 210 days. One offspring is normally produced; the occurrence of twins is very rare. Offspring weigh 3.4 to 6.4 kg and are generally well developed. Newborn males weigh slightly more than females. Weaning occurs between 6 and 8 months and an individual reaches sexual maturity in 3 to 5 years. Births have occurred both on land and in water in captivity. Births taking place in deep water almost always result in the newborn drowning.
Breeding interval: Breeding can occur as often as every 7 to 9 months.
Breeding season: Breeding occurs year round in captivity. Seasonality in the wild is unknown.
Average number of offspring: 1.
Range gestation period: 184 to 210 days.
Range birth mass: 3.4 to 6.4 kg.
Range weaning age: 6 to 8 months.
Range age at sexual or reproductive maturity (female): 3 to 5 years.
Range age at sexual or reproductive maturity (male): 3 to 5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous
Hexaprotodon liberiensis is considered a K-selected species, which means it produces few offspring and invests a lot of energy into offspring development. Newborn calves are left in one place while the mother searches for food, returning about three times a day for suckling. They young are usually able to feed on vegetation after three months. These behaviors have been observed both in captivity and in the wild.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
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- Kingdon, J. 1997. The Kingdon Field Guide to African Mammals. San Diego, California: Academic Press.
- Lang, E. 1990. Pygmy Hippoptamuses. Pp. 58-64 in B Grzimek, ed. Grzimek's Encyclopedia of Mammals, Vol. 5, 1 Edition. New York: McGraw-Hill Publishing Company.
- Leidy, 1991. Pygmy Hippopotamus. Pp. 1350-1351 in R Nowak, ed. Walker's Mammals of the World, Vol. 2, 5 Edition. Baltimore Maryland: Johns Hopkins University Press.