Understanding Hippos: The Third-Largest Land Mammal

Hippos are among the most iconic animals in Africa and hold the distinction of being the third-largest land mammal living on Earth today after elephants and white rhinos. On top of their huge size, these animals have numerous fascinating behaviors and characteristics that have enabled them to adapt to their native environment over the course of millions of years.

This semi-aquatic animal (scientific name: Hippopotamus amphibius) is found across several parts of sub-Saharan Africa, inhabiting wetlands, rivers, lakes, and swamps, among other similar habitats.

Exploring the Size and Habitat of Hippos

These giants tend to weigh between around 2,800 and 7,000 pounds as adults—similar to a car—and grow to lengths of between around 7 and 16 feet, according to the University of Michigan Museum of Zoology's Animal Diversity Web online database.

Some hippos grow even larger, though—the biggest individual ever recorded was a captive individual kept in Germany that weighed almost 10,000 pounds.

While these bulky, barrel-shaped creatures might appear to be clumsy and slow-moving at first glance, they are surprisingly agile on land, capable of moving at speeds of nearly 20 miles per hour.

Hippos spend most of the daylight hours wallowing in water and they are well-adapted to the aquatic environment—for example, their eyes, ears, and nostrils are positioned in such a way on the top of their head that they can see, hear, and breathe while the majority of their body is submerged.

Unique Adaptations of Hippos

Hippos have a membrane that covers their eyes, which protects them while enabling the animal to see underwater. They can even close their nostrils and fold their ears to prevent water from entering their bodies when they are completely submerged.

Hippos can hold their breath for long periods of time—five minutes or even longer—and can even sleep underwater, automatically surfacing to take breaths when necessary without waking up.

Despite all these traits that have enabled them to adapt well to semi-aquatic life, hippos cannot technically swim and their bodies are too dense to float. To move while in the water, these giants essentially leap off the bottom of the body of water they are in before engaging in a galloping motion using their short legs and webbed feet.

The Social Structure and Behavior of Hippos

You may be surprised to learn that hippos, which live up to 50 years in the wild, are actually closely related to whales. The two animal groups are each other's closest living relatives sharing a common ancestor that lived more than 50 million years ago.

Like whales, hippos also lack sweat glands and rely on water to keep cool. But they do produce a thick, oily layer of a red, pigmented fluid that used to be referred to as "blood sweat" because it was once thought to be a mixture of these two components. Now, scientists know this fluid is made up of different acids and acts as a natural sunscreen while also potentially preventing the growth of harmful bacteria.

Hippos are social animals and tend to live in flexible groups of 10 to 30 individuals, although some groups can reach 200 individuals in size. These animals are polygynous, meaning that the male bulls mate with several females in the herd.

Hippos and Human Interaction

Hippos have a reputation for being dangerous to humans, and they are thought to be among the most deadly land mammals. The number of people killed by hippos every year is not known given that no data repository exists on human injury or fatality due to hippo conflict. But some estimates indicate that the figure might be between 500 to 3,000 fatalities annually.

While hippos are generally quite docile, they can be territorial and have been known to act aggressively toward humans in certain situations. Hippos usually attack only if they perceive a threat—for example, when someone stands between them and the water they spend their time in.

According to experts, hippos do not actively seek out people to harm or injure; the issue arises when humans and hippos occupy the same area and compete for resources. Thus, conflicts often occur.

Conservation and Future of Hippos

Hippo populations have experienced a substantial reduction in their former range across Africa, which has principally been caused by habitat loss and over-exploitation. While hippos are protected across most of Africa, illegal killings do still occur, and park authorities may still shoot problem animals.

Despite these challenges, there are a number of measures that may help mitigate conflict between humans and hippos, including educating local communities about the value of hippos within their own culture and the need to conserve the animals.

Ultimately, the future of hippos hinges on the balance between human development and wildlife conservation. As habitats are lost to agriculture and urbanization, it is critical to find ways to coexist with these magnificent creatures.

In conclusion, hippos are not only fascinating creatures but also crucial components of their ecosystems. By understanding their behaviors, habitats, and the challenges they face, we can work towards solutions that protect both hippos and human communities.