Hippopotamus at Giza Zoo

Class: Mammalia Order: Artiodactyla Family: Hippopotamidae Species: Hippopotamus amphibius
Distribution: Hippos are still found in the rivers and lakes of Uganda, Sudan, Somalia, Kenya, northern Democratic Republic of the Congo and Ethiopia, west through Ghana to Gambia, and also in Southern Africa (Botswana, Republic of South Africa, Zimbabwe, and Zambia). A separate population exists in Tanzania and Mozambique.

Habitat:
The preferred habitat of this species is deep water with adjacent reed beds and grasslands.

Description:
Because of their enormous size, hippopotamuses are difficult to weigh in the wild. The average weights for adult males ranged between 1500–1800 kg (3,300–4,000 lbs). Females are smaller than their male counterparts, with average weights measuring between 1300–1,500 kg (2,900–3,300 lbs). Older males can get much larger, reaching at least 3,200 kg (7,100 lbs) and occasionally weighing 4500 kg (9900 lbs). Male hippos appear to continue growing throughout their lives; females reach a maximum weight at around age 25 years.
Hippo's average length is 3.5 meters (11 ft) long, 1.5 meters (5 ft) tall at the shoulder. Hippopotamuses can run faster than a human on land. Estimates of their running speed vary from 30 km/h to 40 km/h, or even 50 km/h (30 mph). Hippo can maintain these higher speeds for only a few hundred meters.

Life span:
They can reach 50 years old.

Diet:
Hippos feed on grass, but have very occasionally been seen eating small animals or scavenging. They eat about 40 kg of grass a day, which is only 1-1.5 % of their body weight - their lifestyle is energy-efficient.

Behavior:
Hippos may occur singly or in groups of up to 30 animals. The central core of social groups appears to be females with their dependent offspring. Adult males vie for control of these herds. Aggression between males is intense. Hippos use their long canine teeth as weapons, and death often results from fighting between males. Most adult male hides are covered with scars from injuries incurred during such fights.

Reproduction:
Hippopotamus is capable of breeding year round, but it experiences seasonal breeding peaks during February and August. The birth of young coincides with months of peak rainfall, October and April. Female hippo experiences a three day estrus, during which she is mated by the resident bull. After a gestation of 227-240 days, the cow gives birth underwater to a single calf, weighing 27-50 kg.
Calves nurse underwater and are frequently seen riding upon their mothers' backs while the mother is in the water. Weaning starts between 6 and 8 months after birth and most calves are fully weaned after a year.
Males reach sexual maturity in the wild between 6 and 14 years of age, whereas females are capable of breeding at 7-15 years of age.

Conservation status:
IUCN Red List: Vulnerable.

References:
http://en.wikipedia.org/wiki/Hippopotamus
http://animaldiversity.ummz.umich.edu/site/accounts/information/Hippopotamus_amphibius.html
http://www.iucnredlist.org/apps/redlist/details/10103/0