Israeli Zoo Reports Success in Breeding Rare Siamang

Finally isolated from those irritating orangutans, the siamang couple at the Ramat Gan Safari Park had a baby, which somebody finally noticed.

Siamang baby
The proud mother siamang Jambi with her new baby (the small thing clinging to her tummy), vocalizing as she swings in the trees (note the engorged throat sac). Tibor Jaeger

Mazal tov: The Siamang couple at the Ramat Gan Safari Park has had a second baby, three years after the first one born to Jambi and Yan failed to survive.

Actually the baby was born about a month and a half ago, not that the zookeepers knew, because the monkeys live in thick brush and the tiny thing was ensconced in his mother's fur. They had known however that mother Jambi, who is 8 years old, was pregnant: she had been in a terrible mood ("rather irritable") for weeks, and at some point her stomach began to expand.

The bonny baby, born bare-skinned except for a tassel on his head, has a downy coat of fur by now, but remains glued to his mother. He won't be walking about by himself for about four months. Meanwhile, 10-year old father Yan is showering affection on his mate. "He's always nice to her but now he's especially nice," says Safari spokeswoman Sagit Horowitz.

Pressed for detail, she explained that according to the keepers most familiar with the monkeys, the irritable male is keeping his temper in check: "He's become very gentle."

"When the baby is about a year old, the father also takes his turn looking after him, which is very unusual in the primate world," stated Horowitz. In siamangs, she says, the male will help groom the baby and play with him.

Breeding bugs

Siamangs are a species of large arboreal gibbon native to the jungles of the Malay Peninsula and Sumatra. Despite a propensity for swinging away from danger through the trees, they are in danger of extinction and are thus governed by the CITES treaties (I and II) , which among other things ensures that zoos do not trade in rare animals – they exchange them for breeding purposes. Jambi had come from England and Yan from France, says Horowitz.

The siamang family, father on right. (Photo: Tibor Jaeger.com)

In nature, siamangs eat mainly leaves, augmented by the odd egg, lizard or fruit – jungles have a lot less fruit than most people imagine. The Safari feeds its siamangs mainly on protein-rich insects, featuring the delicious waxy mealybug, which it breeds for them, says Horowitz. The monkeys also get fresh fruit and vegetables.

It's a good job that Jambi and Yan get along. The species usually, if not categorically, mates for life, unlike say bonobos or some people, though threesomes have reportedly been known.

Mother and baby siamang at the Ramat Gan Safari. (Photo: Tibor Jaeger)

In nature, siamangs are arboreal, swinging agilely from tree to tree with their long arms, a method of locomotion called brachiation. Spiderman, hang your head: the siamang may cover as much as 15 meters in a single jump, and can swing through the canopy as fast as 56 kilometers per hour, says the Safari. They do not cavil at major jumps as long as 15 meters, monkey experts adds.

So how does the Safari keep its siamangs in place, without bars? "They live on two islands with trees in the middle of an artificial lake and can get from one island to the other on swinging ropes," says Horowitz.

Yes, Safari visitors, that's the island complex that used to be occupied by gibbons. When the siamangs first arrived, they were put in with another primate species from the same area – the orangutans. That did not work out well.

"They used to fight with the orangutans. Jambi in particular kept bullying them," says Horowitz. "So we moved them to the island, where they live in isolation, and moved the gibbons in with the orangs."

The reasons siamangs are endangered include habitat destruction and encroachment, and their rather leisurely rate of reproduction.

For a monkey weighing only eight to 13 kilos, they have an extraordinarily long gestation of 7-8 months, which produces a single baby – that will only reach sexual maturity itself after 8-9 years. The Safari can only hope the new baby, which hasn't been named yet, will survive, unlike the first one. If it does, it will probably stay: if however the Safari establishes a breeding colony, it can continue the tradition of trading, to ensure the survival of the species by breeding it in as many places as possible.