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Latest Field News 30/05/2014

Zoo dental study helps wild orangutans

A study on the dental health of orangutans at Chester Zoo could play an essential role in protecting their wild counterparts thousands of miles away in Borneo and Sumatra.

Orangutan

In a bid to help vets in Malaysia and Indonesia, our keepers are gathering new information on the emergence of teeth in their young orangutans.

The research is helping to improve age estimations of orangutans observed in the wild and orphaned orangutans in rehabilitation facilities in South East Asia, whose dates of birth are usually unknown.

Chester Zoo vet Steve Unwin, who also leads the Orangutan Veterinary Advisory Group (OVAG), a community of mostly Malaysian and Indonesia vets working in rehabilitation centres in those regions, said:

“An orangutan is reliant on its mum for the first eight years of its life. But it’s very, very difficult indeed to tell the ages of young orangutans. So, if a rehabilitated youngster is thought to be eight years old but is actually only five, this can potentially affect its chances of survival when it’s reintroduced into the forest.

“That’s where dental emergence studies on zoo-based orangutans which, we of course know the dates of birth of, could be highly relevant for improved age assignment of confiscated orphans in Indonesia and Malaysia.

“This is an excellent example of how zoos, and captive populations of species, can aid conservation efforts in the wild.”

Orangutan dental health
Sumatran orangutan Tripa shows off his baby teeth

Keepers at the zoo are now busy recording when first teeth start to appear before they later wobble and fall out.

“Whereas most people don’t tend to look forward to a trip to the dentist, our orangutans seem to really like having their teeth checked,” said primate keeper Kate Brice.

“That’s because to encourage them to open nice and wide we often use honey which we smear on a surface for them to lick off. As soon as they come over we then have to take a photograph of the insides of their mouths as quick as we can, as before you know it the honey is gone!

“Currently we’re monitoring baby tooth timings for our two young Sumatran orangutans - Tripa and Tuti - who are both just over one year old. We first saw signs of teeth when they reached five months.

“We know orangutans have 20 baby teeth and 32 permanent adult teeth but what we need answers to in particular is whether or not timings relating to the development of permanent incisors, canines and premolars is different in males and females and between Sumatran and Bornean species of orangutans.”

Orangutan dental health - Chester Zoo

Felcity Oram, programme development advisor and PhD student with the orangutan research unit of Chester’s Zoo’s partner in the field – Hutan/Kinabatangan Orangutan Conservation Programme (KOCP), added:

“Better understanding of basic life history is important in order to ensure the continued viability of orangutans in the wild, especially as they increasingly live in human-transformed landscapes.”

Orangutans - or old man of the forest as they are also known - are one of human’s closest relatives. But in the wild the demand for timber, palm oil, roads, agricultural land and space for mining means huge areas of forest have now been lost, taking with it the homes of both Bornean and Sumatran orangutans and pushing them perilously close to extinction.

In October, we're launching a campaign to help further protect orangutans in the wild. Go Orange for Orangutans will urge schools, families, businesses and individuals to help do their bit to save the critically endangered animals. All funds raised through the campaign will help conservationists continue their work to protect orangutans in the forests of Borneo and Sumatra.

Visit www.actforwildlife.org.uk/orange to find out more.

Fast facts

  • Orangutans (and humans) only get one set of molars but two sets of premolars
  • Orangutan dental emergence is markedly slower than in chimpanzees and more closely parallels humans
  • They have 32 permanent adult teeth
  • They have 20 baby (deciduous) teeth
  • New data for tooth emergence is urgently required in four-15 year-olds as permanent teeth emergence timings are especially data deficient. Chester Zoos orangutans in this age range are therefore important participants in this study. This age range is a very important time in the life of a free ranging orangutans, whether a rehabilitant or in the wild, as it is a time of marked growth and developmental change. Better age estimation of animals in this age range could be critical to their survival chances in the wild of a rehabilitant and aid in our understanding of normal maturation in the wild
  • New data is also needed as regards baby or deciduous teeth emergence timings, especially to see if Sumatran and Bornean are different
  • Zoo-based orangutans can therefore supply some key information to help their fellows living in Malaysia and Indonesia both in the wild and orphan rehabilitants
  • Chester Zoo currently has 10 Sumatran and 10 Bornean orangutans (including four which are from Blackpool Zoo who are being looked after whilst their home is being refurbished)
  • Sumatran orangutans are critically endangered and could become the first great ape to become extinct in the wild. Borneans are also critically endangered
  • Chester Zoo is home to the oldest orangutan in the UK, Martha, who arrived in 1965
  • Orangutans are the only non-African great ape
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