Wildlife TV

Learn interesting and funny plant and animal facts with videos and photos

Why do people think that ostriches bury their heads in the sand?

You may have found yourself in an argument with someone who is refusing to see sense and listen to you. You may have found yourself saying that they have buried their head in the sand.

It is a common metaphor that is a part of our cultural vocabulary; we use when people are being ignorant of facts, refusing to acknowledge advice or in denial about their situation. It has been commonly used in this way for centuries, since Roman times. But what is the origin of the phrase? It comes from the ancient observations of the behaviour of animals, namely, ostriches. So, why do ostriches bury their heads in the sand? Well the answer is that they don’t.

It has long been believed that ostriches will bury their heads in the sand to avoid predators; that they are so stupid as to believe that by concealing their heads they become invisible to predators. However, the truth is that this is a myth; there has never been any observation of an ostrich burying its head and yet for centuries the idea has stuck with us. There are, however, many behaviours which ostriches perform that might have given rise to this curious myth.

Ostrich Head and Neck (Struthio camelus)

Ostriches (Struthio camelus) are strange and fascinating birds; is it really true that they bury their heads in sand? If not, why do so many people think so? Photo Credits.

The common ostrich (Struthio camelus) is the world’s largest bird (currently alive). It is found across large swathes of sub-Saharan Africa and, historically, North Africa and Arabia. The first recorded occurrence of a belief that they bury their heads comes from Gaius Plinius Secundus, also known as Pliny The Elder (AD 23 – AD 79) a Roman scholar who invented the idea of the encyclopedia. Pliny spent most of his time observing and recording natural phenomena, including the behaviour or wild animals. He was a great author and philosopher who wrote volumes of information about the natural world, however, not all of it turned out to be entirely accurate. So from where did he get his ideas about ostriches? There are several potential explanations.

Gaius Plinius Secundus (aka Pliny the Elder)

Gaius Plinius Secundus (aka Pliny the Elder) was a Roman scholar who wrote about ostriches hiding their heads to evade detection. He was a great naturalist and even invented encyclopedias, but he was wrong on this one issue. Photo Credits.

Ostriches are extremely fast runners. They have long powerful legs that can accelerate them to up to 70 kilometres per hour; clearing 4 or 5 meters in a single bound. Quite rightly, they use their tremendous speed as their first resort when faced with a threat, however, sometimes, they might be trapped or injured or otherwise unable to escape. When they are not able to run, ostriches will lie down as flat as possible, stretching their necks out flat against the ground. Their necks and heads, incidentally, are often the colour of their habitat’s terrain (sandy brown/grey) and so at a casual glance, only their bodies would be visible, perhaps leading to the assumption that they have buried the rest.

Ostriches are omnivorous, eating a wide variety of things, however, they mostly feed on low level vegetable matter such as roots and fallen seeds, as well as invertebrates such as crickets. They also practice geophagia; picking up stones and pebbles from the ground and swallowing them, keeping them in their gizzards to help grind up and digest food. As a result of this diet, ostriches have their heads down at ground level for large amounts of time. Perhaps this has been misinterpreted and has helped propagate the idea of burying their heads.

Male Ostrich (Struthio camelus) Feeding

Ostriches (Struthio camelus) find most of their food on the ground and so have their heads down often. This may have given rise to the idea that they even bury their heads. Photo Credits.

It has also been suggested that ostriches will lower their heads to ground level in order to scan the horizon for threats. They may simply also lower their heads to ground level to be less obvious to prowling predators when they feel nervous. But the idea that they believe that they can conceal themselves completely by hiding their head is unfounded. Pliny the Elder suggested that they also stuck their heads into bushes to achieve the same effect. This notion is born from the idea that ostriches are ‘stupid‘ animals because they have such tiny brains: Ostriches have brains smaller than their own eyeballs (although they do have the largest eyes of any land animal)! In reality, animal cognition is not as simple as saying that a small brain equals a stupid animal. However, their small heads may have contributed to the myth; when their heads are down at ground level, they are so small that they can be difficult to see, this optical illusion may have led people to believe the animals’ heads were in fact buried.

Ostrich Chick (Struthio camelus)

Adult ostriches (Struthio camelus) grow to be the largest birds on the planet, but the start life as very cute chicks! Photo Credits.

Ultimately we have seen that an ancient misconception has turned into a common metaphor for human behaviour and it has been hard to separate the popular myth from the scientific truth ever since. There are many reasons that might explain why Pliny the Elder first wrote about the idea, but ultimately, we may never know where it came from originally.

Much love,



Clawed Frogs: Nature’s Pregnancy Test

Mating and breeding are fundamental aspects of surviving as a species and although many animals have breeding seasons, humans as a species, do not. This means that women don’t have specific times during the year in which they are more fertile and willing to engage in mating in order to get pregnant. Instead, we go through monthly fertile cycles between the first menstruation (menarche) and menopause. This is good on one hand because it is not necessary to wait for a specific month or months of the year in order to get pregnant but also bad because, as it can occur at any given time, women might fail to notice they are pregnant and not take basic pre-natal care to ensure the survival and best development of the baby.


Old school pregnancy tests

For many reasons it quickly became important to find out if a woman was pregnant or not as soon as possible. Was the queen finally going to provide an heir? Was the future virgin bride not so virgin after all? Was the husband that had just come back from the sea really the father? Being able to tell, with a certain accuracy, if a woman was pregnant or not would solve many problems but we still have no idea how our (very ancient) ancestors were doing it (if they were at all) since no information was ever found. We are aware however that the first known pregnancy test started to be used in the ancient Egyptian and Greek cultures with the use of urine and grains. They would introduce, on one side, urine of the lady that wanted to find out if she was pregnant, and on the other side (as the control subject) the urine of a priest, on bags of barley and wheat. Both bags would be observed for how long germination would occur. If a lady was with child her grains would sprout a lot faster than the priest (we could easily infer he would not be pregnant).

Throughout history many other “urine analysis” techniques were used to find out if women were pregnant, some of them more scientific than others; but it wasn’t until the last century that animals started to be used in the procedure.

With the discovery that the hCG (human chorionic gonadotropin) hormone was produced by the placenta during the first trimester of pregnancy, scientists were able to design a better and more reliable way to test for pregnancy.

This discovery, in the 1930’s, boosted the development of pregnancy test worldwide with very big implications. For the first time in known history, scientists were using live animals such as mice and even rabbits for their testing. Infantile females (non-sexually mature) were injected with the urine of the woman to be tested and later on killed and dissected in order to look for the presence of ovulation in the animal. The ovulation would have been triggered by the hCG presence in the injected urine of pregnant women and would pose as a positive result.

This method, however, meant that for every tested woman we would end up with a dead mouse or rabbit. Luckily for humanity shortly after, still in the 1930’s, a gentleman named Lancelot Hogben found out that he could use a specific genus of frogs, the Xenopus, to get the same results but without having to kill the animal.


Xenopus: 1930’s-1950’s pregnancy test

Clawed frogs (Xenopus) were subjected to the same method; the urine of the woman was injected in its dorsal lymph sac and if the frog produced eggs in the first 12 to 24 hours the woman was with child. The big difference between mice and rabbits and these frog species is that amphibians, unlike mammals, have external fertilization so the new eggs could be easily observed without having to kill and dissect the animal.

By the 1940’s, this test, named the “Hogben Test” in honour of its discoverer, was already widely used in hospitals.

Many facts helped this method achieve worldwide recognition:

  • It was extremely accurate
  • It was very easy to perform
  • Results were achieved in 12-24 hours
  • The frogs were easily bred
  • The frogs were conveniently kept in aquariums
  • Amphibians in general have large eggs which can be easily examined and manipulated
  • Eggs are released outside the animal (they use external fertilization)
  • Clawed frogs reacted to the hCG hormone released by pregnant women
  • Since the frogs didn’t have to be killed and dissected in order to have their eggs examined, they could be used multiple times
African Clawed Frog (Xenopus laevis)

African Clawed Frog (Xenopus laevis)
Photo Credit


Pregnancy tests post-Xenopus

Even though there were many advantages to using this African species in laboratories all over the world, there were a few cons that ultimately made the test obsolete.

  • The clawed frogs (Xenopus) had to be imported from Africa in large numbers
  • Live animals need to be housed, fed and taken care of
  • One disease outbreak in a lab with frogs would be enough to close it down


Eventually science evolved enough that by the 1960’s the Hogben test became obsolete and today we can buy a small, cheap and easy to use pregnancy test that will give a result within minutes and without going through several technicians, scientists and doctors. The same result can be achieved in private and in minutes.

Unfortunately, all the Xenopus testing for decades came with a price. In 2006 researchers found out that this genus might have been the carriers of the (in)famous chytrid fungus, a deadly amphibian fungus that caused the mass extinction and population decline of almost 200 amphibian species all around the world. African clawed frogs are known to be one of the only species of amphibians in the world to be not only immune but also a carrier of this deadly fungus and several decades ago we shipped them all over the world..

There is no treatment for this fungus and the only way to control this mass extinction is through quarantine.A staggering 30% of known amphibian species are currently threatened with extinction  and about 500 amphibian species are so threatened at the moment that no human effort will be fast enough in order to stop its extinction. Projects like the Amphibian Ark are doing their best to help the remaining species we have surviving these dark times. If you can, visit their “How can I help?” page. There are many things all of us can do to help out, either by donating time, money or skills.

Small gestures can make a huge impact on these small creatures.


Até à próxima.


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On Drug Lords and Hippos

We are all familiar with one of Africa’s most iconic animals; the noble hippopotamus (Hippopotamus amphibius). The hippopotamus (or hippo) is a large, aquatic, herbivorous mammal that lives in the waterways of sub-Saharan Africa, however, for the last couple of decades, these animals have embarked on a peculiar experiment and have begun to colonise some of the lakes and rivers of Colombia in South America.

A black and white portrait of Pablo Escobar.

Pablo Escobar was a Colombian drug lord who used his extraordinary wealth to build his own private zoo.

This bizarre story starts with the exploits of one man in the 1980s: Pablo Escobar was a notorious Colombian drug lord who trafficked cocaine and built a crime empire that earned him the title of world’s wealthiest criminal. In the 1980s, Escobar’s cartel controlled 80% of the world’s cocaine industry and he managed to acquire US$30 billion in the process. So where does a billionaire drug lord make his home? Well, in a sprawling, luxurious, palatial estate of course: Escobar built for himself the sprawling Hacienda Nápoles; a 20km2 ranch containing everything from a private airport, to a bullring, to a dinosaur themed playground, but the most important part (for this story) is the zoo. The Hacienda Nápoles zoo contained a huge variety of exotic creatures, smuggled into Colombia from all over the world, many from Africa, including a small herd of 4 hippos.

So what happens next? Well, in 1993, Pablo Escobar was killed in a gun battle with Colombian police leaving the future of his ill-gained property uncertain. The next battle was a legal one, over who was responsible for the sprawling ranch in Antioquia (a region of rural Colombia); Escobar’s family fought with the government for many years over custody, but in the meantime, the hacienda was neglected and fell into disrepair. Thankfully, most of the resident animals of Escobar’s zoo were relocated to zoos in and out of Colombia where they could be cared for properly, but the hippos were left behind (no-one is particularly eager to take on a group of 2 tonne adult hippos). The hippo habitat at the hacienda is, thankfully, quite suited to the animals and they were happy to reside there while the rest of the zoo was slowly reclaimed by the forest.

The story gets interesting again a whole 14 years later in 2007 when local farmers and fishermen in the region began contacting the government’s environmental department reporting encounters with strange animals in Antioquia’s rivers and lakes. As I’m sure you’ve already guessed, these strange animals were Escobar’s hippos. It turns out that the hippo’s lake at Hacienda Nápoles was only separated from the waters beyond by a flimsy fence that was no match for a hefty hippo and adventurous individuals had pushed past the fence and explored the lush waterways beyond, in particular the Río Magdalena (Magdalena river).


The hippopotamus (Hippopotamus amphibius) is native to sub-Saharan Africa, but has been introduced to South America.
Photo Credits.

Colombia turned out to be an ideal place for displaced hippos to prosper, especially the Antioquia region where a tropical climate keeps things warm and wet, and the Magdalena river system provides an ideal habitat due to its shallow and slow moving waters. Most of the regions in Africa from where hippos originate are annually subjected to extended dry periods where hippopotamus populations are forced to battle for survival until the rains return and the rivers swell once more; this is not the case in their new South American home and the Colombian hippos are free to frolic all year round. And ‘frolic‘ they did; Escobar originally smuggled 4 hippos into his zoo (3 females and 1 male) and in new ideal conditions, without adequate management, that population exploded and now there are estimated to be as many as 60 individuals in the area! The original male hippo, named El Viejo (The Old Man) produced several sons who would have been driven away from their maternal group when they reached sexual maturity which triggered their exodus from the zoo, out into the wild.

The hippos have expanded their kingdom quite extensively and there have been sightings as far as 250km away from the zoo. Encounters between local people and the animals has been becoming increasingly common; the region is very sparsely populated but those who live there are predominantly farmers and fishermen. The encounters usually take place on or around the water, but sometimes at night, when the animals come onto land to feed (often on farmers’ crops). We know that hippos can be extremely dangerous animals, one of the most dangerous animals on Earth, and certainly the most dangerous mammal, killing thousands of people every year in Africa, however, fortunately there have yet to be any deaths or serious injuries relating to the Colombian hippos, but it is perhaps just a matter of time. As encounters become more and more intimate, the odds of a deadly conflict increase and there are already reports of baby hippos being brought into homes and children swimming in ponds inhabited by the notoriously grumpy creatures.

The Open Mouth of a Hippo

Hippos use their formidable canines to attack rivals and threats. They are the most dangerous mammals on Earth.
Photo Credits.

So what is the future for these alien animals? That is a complicated question that has many answers. The hippos pose a potential safety risk to local people and threaten regional crops and livestock, but there is also an ecological risk; the hippopotamus does not belong in South America and the population is growing wildly out of control. Everyone involved agrees that something needs to be done, but no-one can seem to agree what is the best course of action. The one thing that is certain is that they can’t go back to the wild in Africa due to disease transmission risks, but there are several other proposed ideas:

  • A dedicated wildlife reserve should be created to house all of the animals once they have been rounded up.

  • All of the males should be identified and castrated so that the population will not grow any further, and eventually die off.

  • The animals should be hunted for food for the local people (apparently hippo tastes remarkably like pork).

  • A full scale culling operation should be used.

  • Every hippo should be captured and relocated to zoos.

Unfortunately, Colombia does not have the finance or resources for many of these options, and there are also serious ethical concerns on how to treat the animals.

Pablo Escobar has left a strange and controversial legacy in Colombia; to many he is a violent, drug dealing, criminal gangster who destabilised the region and caused death and corruption, to others he is a ‘Robin Hood’ character who battled a corrupt government and gave generously to poor people, personally funding schools and hospitals. The hippopotamus population he has left behind in his country is as fascinating and controversial as the man himself.

Colombia has the highest number of terrestrial mammal species of any country in the world and now hippos can join the list, at least until someone can figure out what to do with them!

Much love,