Buzz
Hippopotamuses, often featured in nature documentaries, are enormous, herbivorous creatures known for their weight and aquatic agility. Ranking as the third-largest land animals—surpassed only by elephants and white rhinos—hippos are surprisingly nimble in water. However, they are highly dangerous, responsible for approximately 500 human fatalities annually, making them one of the deadliest mammals on Earth (after humans). Discover more fascinating details about these formidable animals.
1. Hippopotamuses come in two distinct species.
Both species fall under the Hippopotamidae family but belong to different genera. The more common Nile hippo, scientifically known as Hippopotamus amphibious, thrives in aquatic environments throughout sub-Saharan Africa. In contrast, the smaller pygmy hippo, Choeropsis liberiensis, is endangered, with fewer than 2500 individuals remaining in the wild. These rare hippos inhabit rainforests in Sierra Leone, Liberia, and Côte d’Ivoire.
2. The closest relatives of hippos are whales and dolphins.
Although their name translates to 'river horse' in Greek, hippos are not related to horses. They belong to the Artiodactyla order, which includes even-toed ungulates such as pigs, camels, and deer, as well as cetaceans (whales, dolphins, and porpoises). Around 55 million years ago, hippos and whales diverged from a common ancestor. Today, hippos share several traits with cetaceans, including nearly hairless skin and the ability to give birth underwater. Researchers have also discovered that hippos produce clicking sounds underwater, akin to cetacean echolocation.
3. Hippos are perfectly adapted for aquatic life.
Hippos, with their bulky bodies, large heads, and short legs, are naturally designed for water. They spend the majority of their time lounging in lakes, rivers, and wetlands. At night, they venture onto land to feed on grasses and reeds, carving out 'hippo paths' through the vegetation to reach their preferred grazing areas. Remarkably, they even mate and give birth while underwater.
4. Surprisingly, hippos cannot swim.
Despite being semi-aquatic, hippos are unable to swim. Their dense bones make them sink in deep water but are ideal for walking, galloping, or bouncing in shallow rivers and lakes. These bones provide the perfect weight for optimal buoyancy, creating a microgravity-like environment in the water. Hippos can move surprisingly fast both underwater and on land, reaching speeds of up to 24 mph.
5. Fish play a crucial role in maintaining hippos' skin hygiene.
Hippos and fish share a mutually beneficial relationship in their aquatic habitats. African fish species like cichlids and barbels feed on dead skin, algae, and parasites found on hippos' skin and inside their mouths. This not only provides the fish with a food source but also helps remove harmful pathogens from the hippos. Fiona, the famous hippo at the Cincinnati Zoo, enjoys these natural spa treatments from the tilapia in her enclosure.
6. The red 'sweat' of hippos functions as a natural sunscreen.
Hippos are often seen covered in a pinkish substance that resembles sweat or blood. This secretion, composed of hipposudoric acid (red) and norhipposudoric acid (orange), acts as a sunscreen and has antibacterial properties. It helps protect hippos from harmful bacteria like Pseudomonas and Klebsiella, which can cause infections.
7. Hippos are so formidable that even Nile crocodiles avoid them.
Hippos are Africa's most lethal mammals, posing a greater threat to humans than lions or elephants. They frequently target fishermen and boaters, attacking from underwater. Hippos capsize boats, trample people, drag them into lakes, and deliver powerful bites capable of severing limbs, breaking bones, and causing severe tissue damage. In 2014, a hippo overturned a boat in Niger, resulting in 13 deaths, and in 2018, an American woman on a Zimbabwe safari survived a hippo attack after her canoe was flipped, leaving her with a broken leg.
8. Humans have hunted hippos for hundreds of thousands of years.
Homo sapiens and our ancestors hunted hippos for their meat and bones, which were used to craft tools. A 1.4-million-year-old bone hand-axe, made from a hippo femur, is one of the oldest known tools. Hippo meat has been a vital food source since the time of Homo erectus. Archaeologists have uncovered hippo bones with butchering marks at a 700,000-year-old site in Ethiopia and at a 1.9-million-year-old site in Kenya's Turkana Basin.
Ancient Egyptians hunted hippos for their meat, skin, and teeth, often carving protective symbols into their tusk-like canines. Hippo ivory, denser and stronger than elephant ivory, was prized for dentures in the 18th century. George Washington's dentures included hippo ivory, and Paul Revere is believed to have used it in his dental work.
9. President Calvin Coolidge received a hippo as a gift.
During his presidency, Coolidge was gifted several exotic and potentially dangerous animals, including two lions named Tax Reduction and Budget Bureau. Among them was William Johnson Hippopotamus, also known as Billy, a pygmy hippo from Liberia. Billy was presented to Coolidge in 1927 by Harvey Samuel Firestone, a prominent rubber tycoon.
Coolidge quickly donated Billy, along with his other exotic pets, to the National Zoological Park. There, biologists paired him with a female pygmy hippo named Hannah. Billy went on to father 18 calves, each named Gumdrop followed by a Roman numeral (I through XVIII). Today, all pygmy hippos in U.S. zoos are thought to be descendants of Billy.
10. A Louisiana Congressman proposed importing hippos as livestock.
In 1910, amid a beef shortage in the U.S., Representative (later Senator) Robert Broussard of Louisiana introduced a bill on March 24 to import hippos from Africa and release them into the bayous of Florida, Mississippi, and Louisiana. Hippos were seen as a solution to both the meat shortage and the invasive water hyacinth problem, as they could consume the plant while providing ample meat. The New York Times even humorously referred to hippo meat as 'lake cow bacon.' However, Broussard's bill ultimately failed.
11. Colombia is home to a growing population of invasive hippos.
Colombia is the only non-African country where hippos roam freely in the wild. These hippos originated from the private zoo of drug lord Pablo Escobar, who imported one male and three females. After Escobar's death in 1993, the hippos were abandoned and eventually escaped, breeding and spreading along the Magdalena River, Colombia's primary waterway. With abundant food, no natural predators, and no drought, their population thrived.
Today, Colombia has between 80 and 100 wild hippos, with projections suggesting their numbers could exceed 1400 by 2034. Recognized as an invasive species, they pose significant ecological challenges, including altering river ecosystems and displacing native wildlife like manatees and otters. Despite these concerns, public sentiment largely favors the hippos.
