Hear me roar! Every lion has its own unique vocal pattern that individuals use to recognise each other and can help scientists to track population movements, study finds
- Researchers recorded the iconic vocalisations of various lions out in the wild
- They then trained a machine learning algorithm to identify specific lion’s roars
- It found that changes to the lowest frequency of full-bodied roars were key
- These are distinct enough between individual lions that they can be told apart
Every lion has its own unique roar, one that lets the ‘kings of the jungle’ recognise each other and could be used to track population movements, a study has found.
Researchers from Oxford used machine learning to analyse the roars of various lions — picking out the distinguishing frequency that can be used to tell them apart.
According to the experts, lions’ calls are usually issued in a set — with one or two soft moans followed by several loud, full-throated roars and finishing with grunts.
Previous research had suggested that lions could distinguish their peer’s roars from each other — allowing them to identify distant friends and hostile neighbours.
However, it had not previously been clear what aspects of the calls’ structure allowed them to discriminate between those made by different individuals.
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Every lion has its own unique roar, one that lets the ‘kings of the jungle’ recognise each other and could be used to track population movements, a study has found (stock image)
‘African lion numbers are declining and developing cost effective tools for monitoring and ultimately better protecting, populations is a conservation priority,’ said paper author and zoologist Andrew Loveridge of the University of Oxford.
‘The ability to remotely evaluate the number of individual lions in a population from their roars could revolutionise the way in which lion populations are assessed.’
In their study, the researchers developed a wearable device they have dubbed a ‘biologger’ — which, when attached to a lion’s GPS collar, can log both audio recordings and movement data.
From this data, the team were able to cross-reference sounds and locations and associate each lion with their own characteristic roar.
Next, the team trained a pattern-recognition algorithm to ‘learn’ the characteristic features of each individual lion’s roars and then put it through its paces analysing vocal sequences that it had not ‘heard’ before.
The researchers found that the algorithm could assign a recording of a roar to a particular lion with a 91.5 per cent accuracy.
The software revealed that the key to distinguishing between each individual lion’s calls lay in looking at the changing shape of the fundamental, or lowest, frequency of one of the full-throated roars typically made in the middle of a set of vocalisations.
These shapes, the team said, have common features across all lions’ calls — but are also distinct enough between individuals that lions can likely pick up on the subtle differences to tell each other apart.
The software revealed that the key to distinguishing between each individual lion’s calls lay in looking at the shape of the fundamental frequency — or ‘ƒ0‘, highlighted on a spectrogram — of one of the full-throated roars typically made in the middle of a set of vocalisations
‘Being able to accurately distinguish between individual roars […] could facilitate the development of alternative techniques for assessing population density and tracking individual movements across the landscape,’ added paper author Andrew Markham.
With their initial study complete, the researchers are now looking to conduct play-back experiments with modified roars — with the aim of seeing if the call’s frequency alone contains enough information to allow for vocal recognition.
The full findings of the study were published in the journal Bioacoustics.
LIONS: SOME KEY STATISTICS
Modern lions, part of the cat family, first appeared in south and east Africa, before evolving into two groups.
One now lives in eastern and southern Africa, while the other includes lions in west Africa and India.
Like many other animals, male lions are much larger and heavier than females, with the average weight for a male around 416 lbs (189 kg), while for a female it’s 277 lbs (126 kg)
The heaviest male lion recorded was spotted in Kenya and was 600 lbs (272 kg).
Much smaller in comparison, the heaviest female, found in South Africa, was 335 lbs (152 kg).
That is heavier than the weight of more than 50 female domestic cats put together.
Lions have three types of teeth: Incisors, used for gripping and tearing meat; Canines used to rip skin and tear away meat; Carnassial teeth act like a pair of scissors to cut meat.
Lions can open their jaws to up to 11 inches (28 cm) wide, giving them one of the animal kingdom’s biggest bites.
A lion’s paws are similar to a pet cat’s, with five toes on the front paws and four on the back.
Lions have retractable claws, which can grow up to 1.5 inches (38 mm) in length. A fifth toe on the front paw has what is called a deathclaw, which acts like a thumb for holding down prey when eating.
Lion cubs are born with a greyish woolly coat, with dark spots covering most of the back, legs and face which act as camouflage.
At around 12 to 14 months old, male cubs begin to grow longer hair around their chests and necks.
This is the beginning of their mane, which will not have grown properly until they reach the age of two.
Lion cubs are born blind and don’t begin to open their eyes until around three to four days old.
Their eyes are a blue-grey colour at first and begin to change to an orangey brown by the age of two to three months.
Lions have scent glands around their chin, lips, cheeks, whiskers, tail and in-between their toes.
These glands produce an oily substance to keep their fur healthy and waterproof.
If you ever see a picture of a lion curling up its top lip and pulling a funny face, the chances are it’s using something called its
This is a small area in the roof of the mouth that allows a lion to ‘taste’ smells in the air.
By showing their teeth and sticking out their tongues, lions are able to catch hold of a smell to work out if it’s coming from something worth eating.
Lions also have good sense of hearing, and can turn their ears in different directions to listen to sounds all around them.
They are able to hear their prey from a mile (1.6 km) away.
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