Hyenas' laughter signals deciphered

Acoustic analysis of the 'giggle' sound made by spotted hyenas has revealed that the animals' laughter encodes information about age, dominance and identity. Researchers writing in the open access journal BMC Ecology recorded the calls of 26 hyenas in captivity and found that variations in the giggles' pitch and timbre may help hyenas to establish social hierarchies.

Frederic Theunissen, from the University of California at Berkeley, USA, and Nicolas Mathevon, from the Universite Jean Monnet, St. Etienne, France worked with a team of researchers to study the animals in a field station at Berkeley. Theunissen said, 'The hyena's laugh gives receivers cues to assess the social rank of the emitting individual. This may allow hyenas to establish feeding rights and organise their food-gathering activities.'

The researchers found that while the pitch of the giggle reveals a hyena's age, variations in the frequency of notes can encode information about dominant and subordinate status. These vocalisations are mainly produced during food contests by animals that are prevented from securing access to a kill, and have been considered a gesture of submission.

Theunissen and colleagues also suggest that the giggle may be a sign of frustration and that it may be intended to summon help. He said, 'Lions often eat prey previously killed by hyenas. A solitary hyena has no chance when confronted by a lion, whereas a hyena group often can 'mob' one or two lions and get their food back. Giggles could therefore allow the recruitment of allies. Cooperation and competition are everyday components of a hyena's life. When hearing a giggling individual, clan-mate hyenas could receive information about who is getting frustrated (in terms of individual identity, age, status) and decide to join the giggler, or conversely to ignore it or move away.' The researchers plan to further test these hypotheses with playback experiments in the field.

http://www.sciencecentric.com/news/article.php?q=10033024-hyenas-laughter-signals-deciphered

Horrible hyena a real pussycat

01 December 2009

We are not all zoologists. Even so, most of us are quietly confident of three 'facts' about the spotted hyena.

These so-called facts are that they first, are some kind of dog; second, have the most powerful bite for their weight of any land animal; and third and above all, are definitely loathsome, cowardly scavengers.

Those three so-called facts are all wrong, but then it gets even weirder in Hyena
Land.

Not only does the female spotted hyena outrank the male, but she also has an organ that looks exactly like the male's penis.

Even stranger, this is what she gets pregnant through, and even gives birth through.
In Africa, the hyena was believed to be a tool of demons and witches, much like the black cat in medieval European society. Witches and sorcerers were thought to travel either by riding on its back, or by magically turning into a hyena.

They also believed that the 'laughter' of the spotted hyena could not only closely imitate the human voice, but could also call potential victims individually by name, to their doom.

Even though the Masai of Africa traditionally despise the hyena, they will leave out their dead for the hyena to eat.

So let's look at these myth conceptions about the hyena, one at a time.

Firstly, hyenas are actually not a variety of dog. Strange but true, hyenas are closer to the cat.

Cats and dogs are related, in that they are carnivorous mammals with spinal cords. That is, they breastfeed their young and they eat meat.

But about 50 million years ago, there was a splitting of the ways. Dogs padded off along one pathway that led to the family which today includes dogs, wolves and foxes.

The other pathway that led to cats, mongooses and (yes) hyenas continued on, quite separately from dogs.

So, by 15 million years ago, there were at least 30 different species of hyena. But today, only two subfamilies survive.

One subfamily has the aardwolf hyena, which live entirely off termites. Apart from the canines, the teeth have dwindled to mere pegs that can no longer chew meat.
These solitary animals will lick to death up to 30,000 termites each night. So, they're not a particularly ferocious beast.

The other subfamily has: the striped hyena (about 30 to 40 kilograms); the slightly larger brown hyena (about 40 kilograms); and the king of the hyenas, the spotted, or laughing, hyena.

They can all be nasty. The spotted or laughing hyenas can weigh up to 85 kilograms, with the females being larger and heavier than the males. They live south of the Sahara, in rainforests, deserts, swamps and mountains.

They are the most numerous predators in the Serengeti. They have a ginger colour and a unique pattern of spots. The 'laugh' is a signal of fear, or excitement, or being chased.

So the hyenas of today are very closely related to civets and mongooses, closely related to cats, and rather distantly related to the canids, which include dogs, wolves and foxes.

By the way, the early hyenas did not have the bone-crushing molars of today's hyenas. These teeth evolved into existence only some five to seven million years ago.

The largest hyena that we know of was a 200-kilogram hyena, Pachycrocuta. It lived from three million to half-a-million years ago, and had massive teeth that could crush the bones of elephants.

Now mentioning teeth brings us to the second myth about hyenas. This myth conception claims that, weight-for-weight, hyenas have the most powerful bite of any animal.

I myself used to believe this, until I read a fascinating paper by Stephen Wroe from the University of Sydney.

This paper was called Bite Club, and it compared the bite-force quotient of various animals, as related to their body weight (the bite-force quotient is scientific talk for how hard an animal can squeeze its jaws together).

Dr Wroe studied animals both alive and extinct, and both mammal and marsupial. The bite-force quotient was higher in marsupials than in mammals, and it was also higher in animals that consistently attacked animals larger than themselves.

This makes sense. If you want to attack something bigger than yourself, you want to bring some good weapons to the fight.

The spotted hyena scored 117 on the bite-o-meter, only slightly ahead of the lion at 112, but behind the tiger (127), the African hunting dog (142) and well behind the Tasmanian devil at 181.

The all-time winner was the now-extinct Australian marsupial lion at 196.

So hyenas do not have the strongest bite of any animal.

So next time, I'll continue our saga of the amazing hyena, debunking the myth of the cowardly scavenger, and delve into its crazy society and mysterious female anatomy.

http://www.abc.net.au/science/articles/2009/12/01/2758761.htm?site=science/greatmomentsinscience

Horrible hyena a real pussycat

01 December 2009

We are not all zoologists. Even so, most of us are quietly confident of three 'facts' about the spotted hyena.

These so-called facts are that they first, are some kind of dog; second, have the most powerful bite for their weight of any land animal; and third and above all, are definitely loathsome, cowardly scavengers.

Those three so-called facts are all wrong, but then it gets even weirder in Hyena
Land.

Not only does the female spotted hyena outrank the male, but she also has an organ that looks exactly like the male's penis.

Even stranger, this is what she gets pregnant through, and even gives birth through.
In Africa, the hyena was believed to be a tool of demons and witches, much like the black cat in medieval European society. Witches and sorcerers were thought to travel either by riding on its back, or by magically turning into a hyena.

They also believed that the 'laughter' of the spotted hyena could not only closely imitate the human voice, but could also call potential victims individually by name, to their doom.

Even though the Masai of Africa traditionally despise the hyena, they will leave out their dead for the hyena to eat.

So let's look at these myth conceptions about the hyena, one at a time.

Firstly, hyenas are actually not a variety of dog. Strange but true, hyenas are closer to the cat.

Cats and dogs are related, in that they are carnivorous mammals with spinal cords. That is, they breastfeed their young and they eat meat.

But about 50 million years ago, there was a splitting of the ways. Dogs padded off along one pathway that led to the family which today includes dogs, wolves and foxes.

The other pathway that led to cats, mongooses and (yes) hyenas continued on, quite separately from dogs.

So, by 15 million years ago, there were at least 30 different species of hyena. But today, only two subfamilies survive.

One subfamily has the aardwolf hyena, which live entirely off termites. Apart from the canines, the teeth have dwindled to mere pegs that can no longer chew meat.
These solitary animals will lick to death up to 30,000 termites each night. So, they're not a particularly ferocious beast.

The other subfamily has: the striped hyena (about 30 to 40 kilograms); the slightly larger brown hyena (about 40 kilograms); and the king of the hyenas, the spotted, or laughing, hyena.

They can all be nasty. The spotted or laughing hyenas can weigh up to 85 kilograms, with the females being larger and heavier than the males. They live south of the Sahara, in rainforests, deserts, swamps and mountains.

They are the most numerous predators in the Serengeti. They have a ginger colour and a unique pattern of spots. The 'laugh' is a signal of fear, or excitement, or being chased.

So the hyenas of today are very closely related to civets and mongooses, closely related to cats, and rather distantly related to the canids, which include dogs, wolves and foxes.

By the way, the early hyenas did not have the bone-crushing molars of today's hyenas. These teeth evolved into existence only some five to seven million years ago.

The largest hyena that we know of was a 200-kilogram hyena, Pachycrocuta. It lived from three million to half-a-million years ago, and had massive teeth that could crush the bones of elephants.

Now mentioning teeth brings us to the second myth about hyenas. This myth conception claims that, weight-for-weight, hyenas have the most powerful bite of any animal.

I myself used to believe this, until I read a fascinating paper by Stephen Wroe from the University of Sydney.

This paper was called Bite Club, and it compared the bite-force quotient of various animals, as related to their body weight (the bite-force quotient is scientific talk for how hard an animal can squeeze its jaws together).

Dr Wroe studied animals both alive and extinct, and both mammal and marsupial. The bite-force quotient was higher in marsupials than in mammals, and it was also higher in animals that consistently attacked animals larger than themselves.

This makes sense. If you want to attack something bigger than yourself, you want to bring some good weapons to the fight.

The spotted hyena scored 117 on the bite-o-meter, only slightly ahead of the lion at 112, but behind the tiger (127), the African hunting dog (142) and well behind the Tasmanian devil at 181.

The all-time winner was the now-extinct Australian marsupial lion at 196.

So hyenas do not have the strongest bite of any animal.

So next time, I'll continue our saga of the amazing hyena, debunking the myth of the cowardly scavenger, and delve into its crazy society and mysterious female anatomy.

http://www.abc.net.au/science/articles/2009/12/01/2758761.htm?site=science/greatmomentsinscience

Mr Hyena can't be late for dinner

Wednesday, March 25, 2009
Forgetting to feed your pets once in a while is not the end of the world – but it could be a matter of life and death for one man, who has a savage loyal following.

Fearless Yosef Mome has been feeding a pack of hyenas every night for more than 50 years and is too afraid of the consequences to miss a mealtime.

'Impossible. It would be too dangerous. The animals would besiege the house and threaten my family,' said the 60-year-old, who has earned the nickname The Hyena Man.

In fact, the pack has become so tame they sometimes snatch the meat from skewers Mr Mome holds between his teeth to spice up dinner time.

He performs the bizarre spectacle after dusk outside the ancient walled city of Harar in Ethiopia for the benefit of tourists and curious locals.

Despite being attacked by a hyena as a child, Mr Mome says he has no fear of the animals – only respect. 'One must know them and understand them, then nothing will happen.'

He said the feeding tradition began 80 years ago.

His parents had several dogs and the hyenas were attracted to the family house by the smell of leftovers his father would bring home from the butcher's.

'And hungry hyenas are not what we want,' said Mr Mome, so his father started to feed them.

Ever since then, the hyenas – which have the strongest jaws in the animal kingdom – have continued visiting.

Mr Mome plans to train his son Abbas to carry on the ritual – and ensure the continued safety of his family.

http://www.metro.co.uk/news/article.html?Mr_Hyena_cant_be_late_for_dinner&in_article_id=597045&in_page_id=34