The Underwater World of Hippos

Next time you're lucky enough to see a group of hippos lounging around in the water with only their ears, eyes and nostrils showing, think what you'd be able to see if you could jump in with a mask and snorkel.

Hippos spend most of the day in water about 1.5m deep, coming out to feed at night. Being large herbivores, they need to eat enormous amounts of vegetation, and daytime is spent digesting last night's meal. They congregate in territorial groups, with females and subordinate males being controlled by a dominant bull. Hippos are well adapted to their amphibious lifestyle and can spend up to six minutes fully submerged, although they don't usually stay more than two. Mothers suckle their calves underwater in order to protect them from harm by other adults, or by predators such as crocodiles.

The water also protects their skin from drying out and cracking in hot sunshine. As an additional protective measure, hippos secrete a special orange-red "sweat" from modified sweat glands all over their body, which was at one time thought to be blood. Recent research has shown that the "sweat" consists of two unstable pigments which protect the skin by acting as sun block and moisturiser. One of the pigments has antibiotic properties, which may explain why the wounds hippos inflict upon each other when fighting do not seem to become infected.

Hippo Factfile
Size: 1.3m shoulder height
Mass: 1600-3200kg
Hippos reach sexual maturity at 5-8 years.
Females live approximately 30 years and usually produce up to ten young in a lifetime.
The gestation period for a calf is eight months.
Adult hippos can kill the young, so mothers often hide their calves for several days after birth - especially in overcrowded pods.
As it's a grazing animal, the hippo's fearsome teeth are used only as weapons.

White Magic

Conservationists are celebrating the birth of three white lion cubs at Sanbona Wildlife Reserve, a 54,000ha private reserve in South Africa's Western Cape. The lions aren't albinos - they have pigmentation, which shows particularly in the eyes, paw pads and lips. Rather, their rare colouration is the result of a recessive gene and is termed leucism.
For centuries, legends of white lions were passed down in the oral tradition of African people. These accounts recall the appearance of white lions over 400 years ago in the reign of Queen Numbi. strong claims of sightings began to surface in 1928, but it took 47 years before confirmation came, when a litter containing two white cubs was documented at Timbavati Private Nature Reserve in the 1970s.
Tragically there are now no white lions left in the wild. Their tiny population is restricted to breeding and hunting camps in South Africa, zoos around the world and the breeding programme of Las Vegas celebrity performers Siegfried and Roy. However Dr Gaston Savoi of Sanbona plans to introduce the cubs carefully into the wild, with the ultimate objective of returning an integrated pride to their homelands of Timbavati. The project is an alliance between the Mantis Collection and the Global White Lion Protection Trust. www.sanbona.com

Wildfile Snippets

Breeding like…hippos?

Russian zookeepers are claiming a world record for Mary, a 47-year-old hippopotamus who has given birth for the 24th time. "I think it has to be a record: 24 surviving babies is a lot for anyone," commented a spokesman for Kaliningrad Zoo on the Baltic Sea.

Fatal Fungus

Scientists in Southern Africa are mystified by a disease which has been blackening and killing baobab trees for several years. Their best hunch is that a fungus is at fault, but far more research is required to explain the disease fully. There is concern that the damage inflicted on the tree's bulbous trunks by elephants allows the fungus to take hold.

Gentle boost for lemurs

Bristol Zoo Gardens in the UK recently welcomed the birth of a critically endangered Lac Alaotra Gentle lemur. Extremely threatened due to its highly restricted range and specialised habitat, the wild population struggles for survival in the rapidly disappearing papyrus marshes that fringe Lake Alaotra in Madagascar. Despite moves to make the lake a protected area, many of the marshes have been drained to make way for rice paddies. The lemurs are also hunted and kept as pets in local villages.

Shark Alert

The Great white shark may turn out to be more threatened than previously assumed, according to scientists with the respected Swiss-based World Conservation Union. Overfishing and a lack of management are the biggest threats to sharks, while the trade in fins has rocketed over the past two decades. Estimates put the number of sharks netted for the lucrative fin trade at millions, though no hard figures exist. At least ten more shark and ray species will be added to the Union's Red List of Threatened Species, joining the current 82 species which are classified as "threatened".

Mixed news for rhinos

The critically endangered Black rhinoceros could be on its way to recovery, with recent surveys by the World Conservation Union and WWF International indicating a rise of 500 over the last two years, to just over 3600. Better law enforcement and an increase in protected habitat, notably in South Africa where landowners are converting farms into private nature reserves, are behind the increase. Rampant poaching drove rhino numbers down to around 2400 in the mid-1990s from an estimated 65,000 just two decades previously. Poachers typically hack off the horns which are in demand in East Asia for medical purposes and the Middle East where they are used in making dagger handles.
The Black rhino is following a comeback blazed by its bigger cousin the Southern white rhino, which has seen numbers increase from a low of just 50 individuals a century ago to over 11,000.
The picture is less rosy in Zimbabwe, however, where environmentalists have sounded the alarm about an upsurge of poaching amid lawlessness and a crumbling economy.
There is also concern for the two other African sub-species of rhino. The Northern white rhino has been reduced to a single, small population of just over 20 animals in the Democratic Republic of Congo and could soon be wiped out altogether by Sudanese poachers. In Cameroon, the Western black rhino may be in an even worse state, with only a few animals scattered widely.
"Illegal demand for horn, high unemployment, poverty, desire for land, wars and the ready availability of weapons all pose a major threat to rhino populations," said a worried Taye Teferi, WWF's African Rhino Coordinator.