Lions are big. Lions are impressive. Lions are also threatened by hunters and habitat loss. So here are seven reasons why we should celebrate their existence.

We still don’t know why they roar

Only certain species of cats roar, the ‘great’ cats, such as lions, tigers and jaguars, which have a specialised structure in their throats. Lions are thought to roar to communicate, especially over longer distances. But we still don’t know why they roar so deeply.

In 2010, Dr Gustav Peters and Dr Marcell Peters at the Alexander Koenig Zoological Research Museum in Bonn, Germany analysed the average frequencies of long-distance calls made by 27 different species of cat. They confirmed that cat species living in more open types of habitat, such as lions and sand cats, have deeper calls, whereas cats living in denser, forested habitats, such as wildcats, clouded leopards and the little known marbled cat, communicate at a higher pitch.

But that doesn’t make sense, as previous research has found that high pitch calls are disrupted by dense vegetation. Low pitch calls meanwhile are disrupted by air turbulence in open spaces, which means a lion’s deep roar may not travel that well across the open savannah of Africa.

Another suggestion is that big cats simply produce sounds at a lower frequency.

That would explain a lion's roar compared to a smaller cat's miaow, but when the researchers took into account the genetic heritage of each species studied, they found body weight has no effect on the dominant frequencies of its call.

And their manes have long been mysterious

Unique among cats, male lions grow a huge mane of fur around their necks. Consisting of hair up to 23 centimetres long, in colour from almost white to black, the mane covers, to varying degrees, the heads, necks, shoulders and chests of male lions.

It was long assumed that this mane helps protect fighting male lions from injury, an idea even posed by Charles Darwin, one of the originators of evolutionary theory.

But there is another reason why male lions might have manes – it acts as a sexual signal to female lions, indicating the male’s health and virility – for example, males with darker manes show higher levels of testosterone, longer life expectancy and greater survival after wounding, and their cubs enjoy higher survival.

To help resolve the enigma, in 2006 scientists compared patterns of injury, mane development and adult mane morphology in a population of African lions.

They found no compelling evidence that the mane protected male lions against wounding, essentially disproving Darwin’s idea. Though manes may have first evolved for this function, it seems more likely male lions use them to show off to females.

Lions can count

Lions appear to have a rudimentary ability to count.

When a pride of lions hears the roar of a single approaching lion, two or two females, rather than a lone greeter, will always go out to meet the stranger.

But if two approaching lions can be heard, then the resident females up the ante, sending out four of their own and so on.

In their own way, the big cats seem capable of keeping track of how many companions and strangers are around.

Lions can pull funny faces

When a lion smells something interesting it will wrinkle up its nose, retract its lips and clench its teeth, pulling a somewhat pained expression.

This is known as the Flehmen response, and the cats are drawing in the scent through their nostrils, holding it in for several seconds. Other animals also do this, including cat species and ungulates such as horses.

The behaviour helps pass the sent over a specialised sensory organ in the roof of a lion’s mouth, known as the omeronasal organ or Jacobson's organ, which samples the chemicals in the odour.

Lions form street gangs

Lions are the only species of cat that habitually live in large groups, called prides. Across Africa and Asia, lions form prides of varying sizes comprising one or more males and often numerous females and cubs.

But why they do so has remained a mystery. A long-standing idea is that female lions socialise in order to hunt cooperatively. But despite the common sight of multiple females working together to outflank and bring down large prey, there is no clear link between how many lions hunt together and their hunting success.

Another is that lions gather to protect territory. Indeed, a range of animals from social insects to primates form social groups that defend territories against competitors. But while there has been anecdotal evidence that bigger groups have a competitive advantage, the idea had never been rigorously tested over long periods of time.

Only in 2009 did objective evidence emerge for why lions form prides. Ecologists Anna Mosser and Craig Packer of the University of Minnesota in St Paul, US published a 38-year study that analysed the behaviour of 46 lion prides living in the Serengeti National Park, Tanzania.

It revealed lions form prides to defend territory against other lions, not to improve their hunting success.

In doing so, they act much like street gangs, gathering together to protect their turf from interlopers. The bigger the gang, the more successful the lions are at controlling the best areas. Larger prides with more adult females not only produced more cubs, as might be expected, but the females within these prides were less likely to be wounded or killed by other lions.

Lions had an uncertain origin

Humans have likely been aware of lions since the literal dawn of humanity, with our  ancestors long having to live alongside the big cats in Africa. Despite this, we only discovered the details about where lions came from in 2014.

Unravelling the history of the lion has been difficult. Animals living in tropical areas tend to leave fewer fossilised remains behind. Lions have also been persecuted during their recent history, with whole populations being wiped out by human activity. Such gaps in the fossil record, and in the distribution of lions, makes it difficult to reconstruct their past.

So an international team of scientists led Dr Ross Barnett of Durham University, UK turned to the ancient DNA within lion specimens held in collections and museums around the world, including from different subspecies, including the extinct Barbary lion of North Africa, the extinct Iranian lion, and lions from Central and West Africa.

The research confirmed that modern lions' most recent common ancestor lived around 124,000 years ago.
Modern lions then evolved into two groups; one lives in Eastern and Southern Africa, the other includes lions in Central and West Africa, and in India.

This second group is now endangered, meaning half the genetic diversity of modern lions is at risk of extinction.

The research also taught us that lions in West Africa and Central Africa are actually more closely related to the Indian lion than to lions in Somalia or Botswana.

And some lions have suffered an enigmatic fate

There are a few subspecies of lion, some of which are quite enigmatic.

As well as living in Africa, lions also live in India. The last population of free-ranging Asiatic lion (Panthera leo persica) lives in the Gir Protected Area in Gujarat State, western India.

Once critically endangered, this population has been steadily increasing in response to successful conservation initiatives spanning five decades. It still remains at significant risk, though recent studies show that local farmers feel positively about the presence of lions in the area, considering them an integral part of their natural heritage.

Another subspecies, the Barbary lion, is one of the most enigmatic of all large predators, both due to its impressive appearance and uncertainty over its fate.

Once numerous across north Africa, the Barbary lion was the most physically distinctive type of lion, including those living elsewhere in Africa and Asia.

It had an extensive mane, and differences in the shape of its head included a more pointed crown and narrow muzzle. People at the time also talked of it being larger, with different coloured eyes to other lions, though it is unclear whether either difference was real.

Historical records suggest that certain behaviours in Barbary lions were also distinctive, for example, they tended to live in pairs or small family groups rather than the prides familiar in Africa. The last firm record of a Barbary lion is an animal shot in Morocco in 1927, though there is circumstantial evidence that Barbary lions may have survived in the wild in the Atlas Mountains till 1942.

But the subspecies may have lived on, within the blue-blood line of a stock of Royal lions once owned by the Sultan of Morocco, and since bred in zoos. Genetic research is ongoing to establish if the subspecies did survive.

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