Hippos

Hippos are huge. Intuitively I think most people know that! But they really are. They can weigh up to about 3,200 kg, be as long as 5m and 165cm tall, making them one of the largest land animals today. They have skin that varies between purple grey and brownish pink with thick bristles on their heads and tails.

They have a powerful jaw and very sharp teeth, giving it the title of most powerful bite force in all land mammals. In fact, they have been recorded to break full grown crocodile backs with a single bite. In addition to being noted for the power of their jaw, they have the largest gap of any land mammal at 1m wide, and their teeth are made of the hardest ivory in the world – despite this, the ivory is easy to carve and was used to make dentures in the 1700s. So, a hippo’s mouth alone is exceptional in several ways! In spite of this, they are predominantly vegetarian, mainly grass eaters. As a bit of a side note, during the dry season there is less grass available, and sometimes they do get desperate and turn to eating meat.

So, we have a huge creature, with a dangerous jaw, that eats grass (mostly). We also have an animal that lives in Africa and yet has to be careful of getting sunburnt… It’s because of their sensitive skin that they graze at night. Their skin doesn’t have hair or fur to protect it but it does however exude a red liquid which, as far back as the Roman empire, was thought to be blood.

Pliny the Elder explained why, or rather how, the hippo could ooze blood. In summary, Pliny said that the hippo would over eat and become too large, then would find the stump of a freshly cut reed and press its body against it in order to open a vein, thus spilling blood. The hippo would thus avoid falling into a ‘morbid state’. This idea of blood letting as a cure was common in medical treatments at the time.

Of course, it’s not actually blood, and Lucy Cooke explains what is really happening. The slimy red substance is produced by glands under the hippo’s skin and it has amazing properties; it acts like a suncream, is thought to have antibacterial properties and is suggested to work as an insect repellent.

Living both in water and on land means they could have ended up poorly adapted to one or other environments, but the ways they’ve adapted to aquatic environments helps them on land where they can move at up to 30 km an hour. They can maintain that speed for several hundred metres and by keeping three feet on the ground at all time, they do so with stability. In shallow water, their short legs propel them powerfully through the water, with their webbed feet helping them navigate the river bottom. Walking well in water is important as they don’t actually swim, instead they walk on the bottom of the river.

Looking at where their sense organs are placed, we find them high on the head, allowing them to be mostly submerged in water whilst still being able to breathe and remain aware of their surroundings. When they completely submerge, their nostrils close and their ears fold to prevent water from entering. If they’ve been threatened, they can spend up to 30 minutes underwater, holding their breath.

Interestingly, their closest relative is the whale and they communicate in a similar way to whales. When they wallow in the shallow waters (nose, eyes and ears above water), their bellows are heard above water, but the sound is also heard underwater. Above water the sound is transmitted from the nostrils, and below the water, it’s through a blob of blubber on the hippo’s throat. Other hippos can hear the underwater sounds via their jawbone which links to their inner ears. Hippos make clicks underwater like those dolphins used as sonar.

Looking just at their senses and how they communicate, we can see hippos are well adapted to their environment. I’ve talked about this before on my blog, but when I was getting more and more pain and fatigue, I realised I was spending much more time at home. I made the decision to do my best to have my home work well for me. This includes various aids and adaptations, but also bookcases that I love, shelves and shelves of books and an array of photographs and pictures that are meaningful to me. The outcome is that my home feels very me, and helps me to feel grounded. Where the hippo is well adapted to it’s environment, I’ve adapted my environment to suit me.

Family life

Hippos live in groups that are female led. Females control the centre of the resting pool – the safer part – and males rest on the outer banks. As suggested by the use of the phrase resting pool, they are highly sedentary and spend most of their time resting.

As with many species, there comes a time when young males start to compete for dominance and hippos do this by yawning, roaring, jaw clashing and dung showering (they have a backward facing penis to help spray dung). Similar behaviours are involved in territorial battles, with dung and urine used to mark boundaries. Fighting is most intense during the dry season when they are all living more closely together with less food available.

The dry season is also often when hippos conceive. The way hippos approach mating is polygynous, that is one bull will mate with several females from the herd. To find a mate, the dominant male assesses the herd, acting with unusual submission as he smells each female’s bottom. He does this to figure out who’s in heat. Once he’s found his mate, he taunts her, pushing her out the herd into deeper waters. She gets frustrated and lashes out at him. He forces her into submission, forces her head under water and mounts her.

Ahead of giving birth, the female gets protective and aggressive and isolates herself, either on land or in shallow water. Once born, mum can be seen cleaning and cuddling with the baby. Nursing takes place underwater and being able to hold their breath and secure their airway means calves can suckle underwater. However, they can’t hold their breath very long so mums will nudge them to the surface with their snout, providing a support for the calf to take a breath! As with the bear, we have a nurturing, caring mother, that can also become aggressive.

And just because it was interesting, Cooke tells us that: “Hippos have internal gonads, hidden beneath several inches of skin and fat… [their] testicles have been described as ‘highly mobile’ due to their habit of wander about, especially when under threat. Their position can vary by as much as 40 centimetres!”

People and hippos

We’ve touched a little on how aggressive hippos can be, and for this reason, hippos are often darker and more complex that pop culture suggests with images of a roly-poly bumbling animal.

In fact, people and hippos are in conflict across Africa, with it often being said that hippos kill more people in Africa than other species. The reality is that river bank habitats are home to both, with humans encroaching on hippo territory and reducing grassland. Given the amount hippos need to eat, the reduction on grazing food can result in them eating crops. When they venture onto land to feed at night, hippos like to keep a direct line to water so that if they feel vulnerable or threatened they can quickly retreat. If a person unknowingly gets between the hippo and the water, trouble starts. Additionally, fishing in hippo waters can make humans appear to be a threat to a newly born calf.

In spite of this conflict, hippos have a important role to play in the local ecosystem, improving it for humans. For example, the amount of dung they produce, fertilises the waterways, increasing the fish populations which is good news for local fishing.

Their grazing also keeps pastures clear of woody species which benefits other grazing animals. The nightly walk from water to grass creates hippo paths and over time this creates a path for water to flow through in the wet season, creating lagoons and side paths for small fish to retreat to in droughts. As well as benefiting fish, their dung fertilises the riverbanks and helps sustain a wide array of plant and animal life.

Ancient Egypt

The duality of beneficial and danger is reflected in culture. For example, in Ancient Egypt, hippos were both feared and worshipped. The god that brought destruction was a hippo, and so was the god of pregnancy, which reflected the recognition of their good mothering skills. The evil god Typhon was represented as a hippo and was a symbol of impudence, impiety and a symbol of “greedy men who despoil the poor but do not dare to touch the powerful and rich” (Beryl Rowlands).

“Throughout the three millennia of the ancient Egyptian civilization, the hippopotamus was abundant and lived in the Nile river…. To the Egyptians, the hippo possessed powerful religious significance, while also acting as a trophy and a source of meat and honour, depicted in the hieroglyphs of tombs and obelisks, while as a hunted animal it was cruelly pursued, speared and often left to die in its own blood.” – Williams

Goddess Taweret – meaning the great one – was sometimes depicted with the head of a hippo, paws of lioness, back and tail of a crocodile and the breasts and stomach of a pregnant woman. She protected women during pregnancy and childbirth, and also protected young children. She was worshipped throughout ancient Egyptian history.

Ammit was another Egyptian deity, with the head of a croc, body of a cat and rear of a hippo and Ammit was the guardian of the passage to the afterlife.

Just taking a quick look at how the hippo was used to represent various gods and goddesses shows that ancient Egyptians recognised the complexity of the creature.

Ancient Rome onwards

As we’ve seen, hippos were revered by the ancient Egyptians and when it came to Romans, they were exhibited. According to Pliny, the first hippos seen in Rome were displayed in Marcus Scaurus’ spectacles of 59BC.

Moving forward in time, we find them being viewed sceptically, and then as wonderous beings.

In The History of Four-Footed Beasts (1607), Edward Topsell wrote of the hippo, saying:

“Some say that hee is five cubites high, and hath ox-hoofs, three teeth sticking out each side of his mouth, greater out than any other beasts, eared, talyed, and neighing like the horse, in the rest like the Elephant; he hath a mane, a snout turning up, in his inwards not unlike a horse, or asse, without hair.”

Topsell found it easier to accept the existence of unicorns than the existence of hippos, reflecting their absence from England.

An advert in 1799 may either be a spoof, or be referring to the fist hippo in England in modern times, describes the hippo in question as “so perfectly sweet, that it fills the room with a rich perfume” and “so extremely tractable and gentle, that the most timid lady may approach it with perfect safety”. I would strongly deter you from the latter…

Apparently, Mr Brookes who had allegedly purchased the hippo claimed to want to improve English cattle by cross breeding them with the hippo… (Caroline Grigson)

By the Victorian age, attitudes towards the hippo can be summed up by Charles F Partington’s entry in The British Cyclopaedia of Natural History (1835):

“The whole aspect of the hippopotamus is repulsive. It has a very stupid look and yet its air is ferocious; and its mouth is about as ugly a mouth as can be imagined.”

A few years after this entry, a hippo called Obaysh was brough to London Zoo, the first hippo to be seen in Europe since the Roman times. It promptly led to a craze known as ‘hippomania’ but was not the first hippo in England. If you head back past Ancient Rome, past Ancient Egypt and keep heading back in time, hippos were actually found in England. They thrived anywhere that was ice free and warm enough to support their huge appetite for grass and their bones have been found as far north as Stockton on Tees, in Wales and across the South of England, including under Trafalgar Square.

Over in Australia, in the late 19^th and early 20^th century, a zoological garden was being constructed. The main objective was to “introduce, acclimatise, domesticate and then liberate select animal, insect and bird species from England” with the goal of diversifying the agricultural industry in South Australia and essentially making it look like England. The plan was it would include spaces for a wide array of animals, including, of course, a hippo.

It appears as though a motive for including the hippo was part of effort to invoke a colonial ‘display’ of exotic animals from lands that England had ‘conquered’. This required a certain array of staple animals such as elephants, lions, rhinos and bears, in addition to the hippo. Some of the exhibits were given special enclosures to reflect their status, with the Egyptian hippo house being added in 1901. To acquire the hippo, the governor used his colonial influence. The hippo went on to die within a year and the South Australian Museum acquired its skin for their own display. A later hippo died in 1929 when someone threw a rubber ball into its cage and it choked on it. Obviously, this doesn’t make for a great story, but I wanted to include it as it shows the symbolic importance of the hippo in colonial eyes.

And over in contemporary Colombia…

Pablo Escobar also works his way into our tales of hippos… Escobar, having made a lot of money through cocaine, wanted it all. And with that, came the idea of a private zoo. Over the years various creatures were smuggled into Colombia, including hippos. There were 3 females and one male called El Viejo (or Old Man). In the early 1990s, Escobar was shot by military police and the entire menagerie was rehomed, minus the hippos who were too hard to transport.

The hippos carried on living there, in what turned out to be a great environment for them, and populations grew. Hippos are however very territorial, so when young males reached maturity, Old Man would kick them out. The area surrounding the hippo pond was rich in waterways, the kind of waterways that would allow young male hippos to travel easily through the Colombian countryside. In Africa this would be fine, the young males would find a female hippo and produce their own baby hippos… In Colombia the outcome is less positive… essentially leading to a lot of sexually frustrated young male hippos…Hippos aren’t small animals and sexually frustrated young male hippos have been causing chaos with their bulk. In addition to damaging crops and the risk to people, the hippos also potentially have the power to change the environment, impacting on local Colombian plants and animals.

As we saw earlier, in Africa, hippos and their environment are much more finely tuned than in Colombia which made me wonder about the effects on us of being in the wrong place. Whether it’s in the wrong country or the wrong job, it surely has an impact? For example, I’ve been in jobs which weren’t a good fit and they impacted on my mental health.

Hippos and names

In my research I came across a couple of references to hippos and names. Firstly, in Ghana, some people celebrate hippos and see them as sacred. It is thought that hippos protected people from enemies and there’s a post puberty naming rite which involves going to the river to get a name from a god, hippo is the messenger, linking god and human.

There’s also a story from which explains why the hippo lives in water. Tortoise had a good life except for one thing; Hippo lived nearby and Hippo had huge and heavy feet which were a danger to Tortoise. One day Hippo had a feast and during this, he said “Friends, you have come to eat at my table, but none of you know my name”. Shocked, the animals realised it was true.  Hippo told them if they didn’t know his name then they couldn’t eat at his table, confident that only Hippo’s many wives knew his name. Tortoise asked what Hippo would do if one of the animals did know his name and Hippo said if that was the case then he would do whatever the animal wanted at another feast.  Come feast day, Tortoise had managed to find out Hippos name and thus Hippo, or Istantim as it turned out he was called, had to do whatever Tortoise wanted.  As we know, Tortoise had a nice life and all he wanted was not to be endangered by Hippo’s feet so he asked him and his wives to live in the river so he could walk on land without danger.  Hippo agreed and has lived in the river ever since.

Wrap up

About 2000 words later and we’ve been on quite a journey to get to know the hippo. We’ve seen the importance of living in the right environment, the complex role of mother as nurturing and violent, and we’ve seen the changing views of hippos throughout history. Leaving us with a reminder that time and culture have a strong impact on how we view things.

Reading

• The unexpected truth about animals, Lucy Cooke
• The Mythical Zoo, Boria Sax
• Animals in Roman Life and Art, J M Toynbee
• Hippopotamus, Edgar Williams
• Caroline Grigson, Menagerie: The history of exotic animals in England
• Animal Diversity
• How did African Hippos end up in Colombia