Transmitters implanted in orangutans for tracking after release into the wild

For the first time transmitters have been implanted in orangutans to track their daily movements. The Sabah Wildlife Department (SWD) has implanted transmitters into three orangutans that have been released back into the wild from Sepilok Orangutan Rehabilitation Center in the Malaysian state of Sabah on the island of Borneo.

"Over the years, we have been actively releasing a small number of orangutans back into the forest, however we have had no way of monitoring them after release," explained SWD Director Laurentius Ambu in a statement. Placing a radio-tracking collar on orangutans has proven unworkable, because the great apes quickly learned how to take off the collars.

The three orangutans with transmitters are doing just fine, according to SWD Chief Field Veterinarian, Dr. Senthilvel Nathan.

The transmitter implanted into the orang-utans are 35 millimeters in diameter and 10 millimeters wide.
"After the surgery to place the implants, we have been watching them closely and our rangers have had time to practice with the tracking equipment within the jungle of Sepilok, we are confident about using this method," said Senthilvel. "The transmitter is placed in the neck area where the skin is thick and has fat deposits. We can also turn the device on and off using a magnet without having to surgically remove it first." Each transmitter is about 35 millimeters in diameter and 10 millimeters wide.

Prior to the transmitters being inserted into rehabilitated orangutans, they were tested on captive apes.

"Before coming to Sabah, Dr. [Christain] Waltzer and Dr. [Thierry] Petit tested this method on captive orangutans in France on the 18th of March this year to see whether it had any harmful effects to the orangutan," explained Laurentius. "Following their success in France, my Department then proceeded with their assistance to implant three orangutans in Sepilok late September."

Laurentius said that the safety and welfare of the animals implanted with the transmitters was the most important factor.

Thousands of orangutans are in rehabilitation centers. Many of these apes were orphaned after their mothers were killed by palm oil plantation workers or loggers as pests. Large-scale deforestation and human-started fires can lead starving orangutans into palm oil plantations for food. In addition, orangutans are often captured for the illegal pet trade.

Bornean orangutans are classified as Endangered by the IUCN Red List, while Sumatran orangutans are considered Critically Endangered. Both species' populations are on the decline.


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