Scientists have deciphered the secrets of gibbon “speech” – discovering that the apes are sophisticated communicators using separate and distinct whispers to talk to their companions.
The research is so significant that it could provide clues on the evolution of human speech and also suggests that other animal species could speak a more precise language than has been previously thought, according to lead author Dr Esther Clarke of Durham University.
Her study found that gibbons produce different categories of “hoo” calls – relatively quiet sounds that are distinct from their more melodic “song” calls.
These categories of call allow the animals to distinguish when their fellow gibbons are foraging for food, alerting them to distant noises or warning others about the presence of predators.
In addition, Dr Clarke found that each category of “hoo” call can be broken down further, allowing gibbons to be even more specific in their communication.
A warning about lurking raptor birds, for example, sounds different to one about pythons or clouded leopards – being pitched at a particularly low frequency to ensure it is too deep for the birds of prey to hear. The warning call denoting the presence of tigers and leopards is the same because they belong to the same class of big cats, the research found.
10 best zoos in the UK
10 best zoos in the UK
1/10 Marwell Zoo
This 140-acre park near Winchester is home to hundreds of exotic and endangered species, ranging from ring-tailed coatis to majestic giraffes, endangered tigers to frilled lizards, curious meerkats to pygmy hippos all set in beautiful, landscaped surroundings. This summer the zoo is opening Wild Explorers, their biggest exhibit to date, hosting some of Africa’s most spectacular wildlife. Online adults £17.26; child £13.62. Under 3s go free. www.marwell.org.uk
2/10 Paignton Zoo
This leafy, shady gem of a zoo was one of the first places in the UK to combine zoological and botanical gardens. It now boasts around 2,000 animals and 1,600 plant species, making for a wonderful place to explore, plus it's been leading the zoo world in ethical trading for years. Watch out for the new male lion Lucifer. Online adults £16.50; child £12. Under 3s go free. www.paigntonzoo.org.uk
3/10 Bristol Zoo
Though this zoo may be a modest 12 acres, it is home to over 450 species. What’s more, being one of the smaller zoos of the world, they’ve been forced to use their space cleverly and efficiently. The new gorilla house, for instance, is an award-winning enclosure, with a glass-roofed viewing area that you can walk over – a world first. New for 2015 are 13 huge and incredibly life-like animatronic Big Bugs, that will make the zoo their home for six months this summer. Online adult £14.53; child £9.09. Under 2s go free. www.bristolzoo.org.uk
4/10 Chester Zoo
This is the most visited zoo in the UK and rated among the top 15 zoos in the world. There’s an impressive 12,0000 animals from over 400 species, as well as a particularly exciting £30m project underway that will take visitors on a personal conservation expedition through the Philippines, Bali, Sulawesi, Sumb and Sumatra, just like the great explorers. Online child £14.72; child £11.86. Under 3s go free. www.chesterzoo.org
5/10 Howlett’s Wild Animal Park
Howlett’s, which was initially set up as a private zoo and is celebrating its 40th birthday this year, made news for unfortunate reasons back in the 90s – the keeper was eaten by a tiger. Even though you can still have close encounters with the big cats, they’re thankfully not that close, and there are lots of other amazing animals in this fabulous, natural-looking 90-acre park too. Online adult £19.95; child £15.95. Under 3s go free. www.aspinallfoundation.org/howletts
6/10 ZSL London Zoo
This is the world’s oldest scientific zoo and currently home to more than 750 different species. Having opened the world’s first aquarium, reptile house and insect house, innovation is still high on its agenda and whilst last year witnessed a brand new Pygmy hippo exhibit, this year’s exciting news is the new ‘In with the Lemurs’ exhibit, which opens on Saturday 28 March. Online adult £21.81; child £15.91. Under 3s go free. www.zsl.org
7/10 Whipsnade Zoo
The UK’s largest zoo is set in a beautiful 600 acres, featuring over 2,500 animals, many of which are jumbo size, such as the elephants, rhinos, tigers, African lions, brown bears, zebras, moose and hippos. It’s also got the UK’s largest herd of Asian elephants, which you can watch getting taken for a stroll around the zoo most afternoons. Don’t miss out on the steam railway, which offers great views of many of the animals. Online adult £25; child £18. Under 3s go free. www.zsl.org/zsl-whipsnade-zoo
8/10 Edinburgh Zoo
This 82 acre zoo is the only zoo in the UK to care for giant pandas and koalas. Other animal highlights include a young baby chimp in their award winning Budongo Trail enclosure, a baby tapir, Indian rhinos, sun bears and a famous daily penguin parade. From April 3 to November 1 the zoo has the added bonus of a life-size animatronic exhibition of dinosaurs – Dinosaurs Return! Online adult £17.00; child £12.50 Under 3s go free www.edinburghzoo.org.uk
9/10 Welsh Mountain Zoo
Some TripAdvisor reviewers complain about the hills. But the zoo’s name should be a bit of a giveaway that it’s not flat. Yes, you’ll be tired, but there’s so much that make it worth it, including an amazing sea lion show, the macaws flying around you, and animals including snow leopards, tigers, otters, lemurs and bears. The keepers are keen to answer questions. Online adult £10.95; child £8.25. Under 3s go free. www.welshmountainzoo.org
10/10 Colchester Zoo
This delightful zoo with over 270 species in 60 acres is particularly child-friendly, with lots of hands on experiences and over 50 daily displays, as well as four adventure play areas and an undercover soft play area. It stays fresh by continually expanding and kids will love the Madagascar Express road train. Online adult £21.99; child £14.99. Under 3s go free www.colchesterzoo.org
Dr Clarke says that she set out to analyse the loud and conspicuous songs that gibbons are mainly known for. But sitting in the forests of north-east Thailand she began to notice distinct variations – and patterns – in the way that the quieter calls were being used.
“It’s amazing. I went out to study the song but I started to see other patterns and started to analyse them. The hoo made when a raptor approached was noticeably more nasally than the others,” said Dr Clarke, adding that the discovery that gibbon communication is far more sophisticated than previously thought has implications across the animal kingdom.
“It could be that, to give a hypothetical example, we think of a cat as having, say, five calls – well maybe it actually has 25 calls and we’ve been lumping lots of distinct calls together when they are actually graded,” she said.
Gibbon hoo calls were first identified in the 1940s, yet their intricacies have gone largely unanalysed because they are so quiet and virtually indistinguishable to the human ear. They are also difficult to record.
“These animals are extraordinary vocal creatures and give us the rare opportunity to study the evolution of complex vocal communication in a non-human primate,” said Dr Clarke.
“In the future, gibbon vocalisations may reveal much about the processes that shape vocal communications, and because they are an ape species, they may be one of our best hopes at tracing the evolution of human communication.”
The researchers spent almost four months following groups of lar gibbons around the forests of north-east Thailand. The gibbons were usually followed from the first encounter in the morning until they had located their evening sleeping tree, while researchers recorded their hoos and noted the event that elicited the response.
From the recordings they extracted a total of more than 450 hoo sounds and used computer analysis to find links between audio patterns and the context in which they were recorded. While both male and female gibbons displayed similar hoo calls, female calls were lower in frequency than the male ones, according to the research, published in the journal BMC Evolutionary Biology.
Females also did not produce hoo sounds when they were encountering neighbours and often remained passive and removed, while males, however, engaged and interacted with neighbouring individuals, the research found.