A new study shows that the muscle mass of Bornean orangutans was significantly lower during periods when less fruit was available. Habitat destruction and threats connected to climate change makes the situation even more challenging.
Habitat loss is one of the biggest threats to the orangutans in Borneo, declared critically endangered by the IUCN. Now a new remarkable study emphasizes that protection of the rainforest is absolutely vital for the survival of the orangutans.
The researchers behind the study found that the muscle mass of the Bornean orangutan dropped significantly when fruit availability was low. This is a remarkable finding, as orangutans are known to be particularly good at storing and using fat for energy and managing through periods when food is scarce.
As climate change and clearing of rainforests are making it harder to find food, the fat reserves the orangutans build up during periods of high fruit availability is simply not enough for periods when fruit is scarce. This makes it quite clear that further disruption of the orangutans’ fruit supply could have consequences for their survival.
“Conservation plans must consider the availability of fruit in forest patches or corridors that orangutans may need to occupy as deforestation continues across their range,” said lead author Caitlin A. O’Connell, at Rutgers University-New Brunwick, in a press release.
Males and females of all ages lost muscle mass
The researchers measured the amount of the waste product creatinine in wild orangutan urine to estimate how much muscle mass the animals had during periods of low availability of fruits compared to when fruit was abundant.
The 1,130 samples examined were collected between 2009 and 2017.
Both male and female orangutans of all ages were found to have reduced muscle mass during periods when fruit was scarce. This means that the primates had used up most of their fat reserves and burned muscle mass instead.
“Orangutans seem to go through cycles of building fat and possibly muscle mass and then using fat and muscle for energy when preferred fruits are scarce and caloric intake is greatly reduced,” says Erin Vogel, senior author of the study and head of the Laboratory for Primate Dietary Ecology and Physiology, that conducted the research.
Research results help protect orangutans
The study, published in the scientific journal Scientific Reports, is led by researchers at Rutgers University and based on data collected in the Mawas area in Borneo, at the Tuanan Research Station that Save the Orangutan collaborates with.
“Research results such as these are important in relation to the prioritization of our efforts to save the critically endangered orangutan,” says Hanne Gürtler, director at Save the Orangutan.
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