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,

-Nick

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Tom and Jerry: Fatal attraction or something else?

How many of us grew up watching Tom the cat and Jerry the mouse constantly fighting and teasing each other to our own amusement? This show created in 1940 has been a source of entertainment for millions of children worldwide for decades. It shows us the reality of the animosity between cats and mice, but how real is it?
Do cats and mice really hate each other? Do they fight? Do naughty mice track down, tease and get cats in trouble?
The answer to all these questions might be slightly different than you think.

Domestic cats and urban mice are natural enemies the same way that lions and zebras are. One is the predator and one is the prey and while the former does whatever it takes to track down and hunt the other, the latter would do all it can to avoid that fate. They don’t exactly hate or fight each other for their own entertainment, they just do what they need to do to in order to survive.

Tom the cat chasing Jerry the mouse. From Warner Bros

Tom and Jerry   © Warner Bros

So why does Jerry keep on trying to chase and annoy Tom? Wouldn’t he just leave him alone and try to be sneaky and quiet as a mouse to the best of his abilities as that would be the difference between survival and being a snack?
Scientifically speaking there is one very good explanation to why Jerry does this (apart from the fact that they are clearly just cartoons and not realistic interpretations of cat-mouse interactions).

There’s a very well known parasite called Toxoplasma gondii that is the source of one of the most feared diseases for pregnant women, toxoplasmosis. While in humans it can cause life long damage if passed from pregnant mother to fetus, in mice the consequences are quite different.

Mice have evolved a healthy avoidance of predators, especially cats, for millions of years. They can detect signs of the presence of felines and alter their behaviour in order to avoid crossing its path. If it wasn’t for this trait passed from generation to generation we wouldn’t have mice nowadays.

But this is nothing special. All living beings strive for survival and that doesn’t exclude the parasitic protozoan, Toxoplasma gondii. Our friend gondii, even though it is able to live inside almost any warm blooded animal, has a thing for cats. They live their lives either inside a cat or doing whatever they can to convince another animal to get inside one. Over millions of years of evolution they have perfected their technique.

 

This is a conversation I imagined went between gondii pals:

  • “Hey Steve have you seen Carlos recently? Ever since he met that cat he’s doing well in his life. He can even reproduce sexually now!”
  • “No way Andre! I thought we could only reproduce asexuality. I must try this cat technique. How does this cat thing work?”
  • “It seems that we need to get ourselves inside a cat’s stomach and once we’re there it’s like heaven or something. That’s what Carlos told me though but he tends to overreact, you know that.”
  • “I must try this anyway. The problem is that we are inside a mouse now and they hate cats. How can we make this work?”
  • “Hum.. I know it! Let’s just make this mouse think that cats’ smell is the best smell in the world. Instead of avoiding it, it must get so excited about it that it will do its best to find the cat. Once it finds it we know what happens.. the cat will just eat our host, the mouse, and we end up in the cat’s stomach just as planned!”
  • “Dude, you’re a genius. Let’s do this!”

 

And this is pretty much what happens (with some creativity from my part). Toxoplasma gondii is capable of permanently changing the mouse host’s behaviour for its own benefit. This parasite increases the activity of the limbic regions of the mouse’s brain to react to a cat’s urine with sexual attraction instead of fear, forcing the mouse to seek the sexy company of the cat instead of hiding and escaping it.

The funny thing is that studies even show that this fatal attraction doesn’t happen with other species, only between cats and mice. It takes a Tom and Jerry for this scene to happen and all the other normal behaviours, senses and general health of the mouse remain unaltered. They just seem to suddenly feel extremely attracted to sexy cats..

That would explain why Jerry is so obsessed with Tom; always trying to get him in trouble, tease him and being naughty in general. He’s just a mouse in love..

 

Jerry the mouse kissing Tom the cat. From Warner Bros

Tom and Jerry   © Warner Bros

That’s all folks!

~Sofia.

 

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Is Immortality Real?

Immortality has been a subject that has fascinated human beings for the longest time. Many legends and mythologies discuss the possibility of supernatural beings and creatures with everlasting life and tell tales of heroes and adventurers seeking the fountain of youth or the elixir of life. In reality, humans are forced to be content with what little time we have on this Earth but left wondering; is immortality possible?

Ageing and eventually dying are natural processes that are a part of the rules of life, however, there are a few organisms that are capable of bending or even breaking these rules.

The animal kingdom is richly diverse and, as you might expect, different animals have vastly different lifespans and many have very brief lives, for example, the worm-like gastrotrich only has a few precious days of life in which to do all of its eating, fighting and mating.

 

Gastrotrich

A gastrotrich is a tiny worm-like aquatic creature that has one of the shortest lifespans in the natural world, only a few days. Photo Credits.

On the other end of the scale are animals that are extremely long-lived. An Aldabra giant tortoise (Aldabrachelys gigantea) that died in a zoo in India in 2006 was believed to have been born in around 1750 making him over 250 years old! The oldest mammals are believed to be bow-head whales (Balaena mysticetus); one individual caught in 2007 was found to have a 19th century harpoon embedded in its neck!

These remarkable cases might make our human lifespans seem measly by comparison, however, there are some organisms who live on a time-scale far beyond what we could ever experience. Some species of Antarctic glass sponges, hexactinellids, could live for as long as 15,000 years! Imagine a life longer than the whole history of human civilization.

 

Antarctic Hexactinellid Glass Sponges

Hexactinellids are glass sponges found in Antarctic waters. They are actually animals and may live for as long as 15,000 years! Photo Credits.

Longevity is impressive, but it is quite different from immortality. As unbelievable as it may seem, however, there are organisms that may be able to live forever.

Lobsters (family: Nephropidae) are animals that we are quite familiar with (mainly as an expensive meal), but they have some fascinating characteristics, most notably; they do not age. Lobsters grow continually throughout their lives but they do not get weaker or lose any function as they go, indeed, it has also been suggested that they become more and more fertile as they grow. A giant lobster (named George) was caught off the coast of Newfoundland in 2008 and was believed to have been approximately 140 years old! It is theorised that if left alone, lobsters might have the potential for immortality, growing indefinitely until they are killed by an external force such as a predator or disease. Lobsters achieve their longevity thanks to enzymes that repair damage to their DNA.

 

Lobster

Lobsters are a family of marine crustaceans. They grow continually throughout their lives but do not age. Photo Credits.

Turritopsis dohrnii is a species of tiny jellyfish that has a unique lifestyle that potentially qualifies it as immortal. These creatures live their lives up until a certain point, when conditions are right, when they will regress back to their infant form, a polyp. Almost like Benjamin Button, they age in reverse but they can repeat this cycle many times, potentially forever. Each time they revert to their immature stage, they are also capable of budding and producing whole new colonies of individuals.

So it seems as if some creatures have unlocked the secrets of immortality, however, immortality is quite different from invincibility. The process of ageing is also called senescence; this is where cells and organs deteriorate over time, whether as a result of being exposed to the stresses of everyday living, or the gradually increasing ineffectiveness of DNA replication. However, organisms that have beaten senescence are not guaranteed never ending life, there are my threats to their existence such as disease, fatal injury, predation etc. For example, the ‘Benjamin Button jellyfish’ rarely gets to even complete one of its life cycles in the wild because it is usually eaten by something first!

There are creatures that also attempt invincibility too: Tardigrades (sometimes called by the cuter names water bears or moss pigs) are microscopic animals that have a remarkable ability to survive extreme conditions; they earn the title of ‘extremophile‘. It seems to be very hard to kill a tardigrade; they can survive extreme sub-zero temperatures as easily as boiling water, they can survive the extreme pressures of the deep ocean as easily as the vacuum of space, they can survive without any food or water for years on end and can even tolerate extremely strong radiation. They can be found almost everywhere on Earth and have lived happily for tens of millions of years. Individual tardigrades can live for several decades depending on environmental conditions; not immortal but pretty close to indestructible!

 

A Tardigrade, or Water Bear

Tardigrades, or Water Bears, are microscopic animals that can survive almost any extreme condition. Photo Credits.

Humans have accomplished many great things, but sometimes we are reminded how fragile we are as animals. The natural world is full of amazing creatures with abilities that can humble us. Perhaps there are things we can learn from them and someday have a chance at immortality ourselves!

Thanks for reading!

Much love,

-Nick

 

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