Hai Phong Cat Ba langurs , the world's most endangered species, have grown from 57 to 76 individuals but are still negatively impacted by tourism.
In mid-June, Mr. Mai Sy Luan, 41 years old, a project officer for the conservation of Cat Ba langurs, woke up at 4am to go to Lan Ha Bay according to a half-month field trip plan. He took a canoe from Cat Beo wharf, Cat Ba town, and traveled around the islands marked with the presence of langurs such as Cua Dong, Ham Lon, and Nam Cat. "Every day I have to search, record their movements, and living habits. This work has been repeated for 14 years," Mr. Luan said.
Mr. Luan has been following the Cat Ba langurs for 14 years. Photo: Xuan Hoa
The Cat Ba langur (Trachypithecus poliocephalus) is one of five primate species endemic to Vietnam, along with the Delacour's langur, Tonkin snub-nosed monkey, grey-shanked douc langur, and Oriental black-crested gibbon. This species is listed in the Vietnam Red Book and the International Union for Conservation of Nature (IUCN) Red List, and is classified as the most endangered primate in the world.
Mr. Luan said that there was once a view that the Cat Ba langur and the white-headed langur in southern China were the closest relatives. However, according to research by the Cat Ba langur conservation project and the Göttingen Primate Research Center, Germany, both species evolved from the Francois langur (white-cheeked black langur). The Cat Ba langur separated from the Francois langur about half a million years earlier than the white-headed langur and is currently not found anywhere else in the world outside the Cat Ba archipelago.
The Cat Ba langur is quite large with a body length of 47-53 cm, and a tail nearly twice as long as its body, helping it maintain balance when moving. The yellow tuft of hair on its head will fade over the years. The lifespan of the Cat Ba langur is about 25 years.
Cat Ba langurs in the Cua Dong area are eating leaves. Video: Neahga Leonard
Female langurs give birth to one baby at a time, after 6 months of pregnancy. The baby langurs have orange-yellow fur, turning black after about 2 months. The baby langurs cling to their mother, and must feel truly safe and in a private area to explore the world on their own. When moving, the baby langurs will be held against the chest of their mother or other older members of the group. When they reach 6 years old, the langurs will be expelled from the group. When they feel strong enough, the male langurs will challenge the leader to become the leader.
After a battle for survival, if the new male wins, he will try to kill the old male's young. This is a natural behavior but also causes many young to be born without being able to mature.
Cat Ba langurs often climb tall trees or jagged, sharp limestone mountains near the sea to forage. Their food is leaves, forest fruits, and even many poisonous ones like lacquer fruit. "They also know how to dip their tails into the sea water to try to drink when the sun is strong, there is a drought, and the rocky mountains have no water," said Mr. Luan.
When the weather is still cool, the langurs will move to the limestone mountain area near the sea to find leaves and fruits. At around 9am, they go into the forest and only go into the cave to rest at night. That is why Mr. Luan's work often starts very early. "The cave entrance often has yellow streaks left by the langurs' urine. We rely on those traces to find them," Mr. Luan explained.
Cat Ba langurs in the Cua Dong area of Lan Ha Bay. Photo: Neahga Leonard
While the herd is foraging and playing, the leader will stand on a high mountain peak to observe, occasionally making warning howls and growls. If it senses great danger, the leader will alert the herd to retreat to a safe place.
In addition to large herds, many male langurs live freely or gather in groups to wander deep in the forest. At times, some males disappear for months and then reappear. "This makes counting very difficult. We have to make a convention that any animal that has not appeared for 6 months will be removed from the count list," said Mr. Luan.
The langurs also have the ability to sit still for a long time, especially the male leader. "Sometimes we sit and compete with them but have to give up," said Mr. Luan, adding that because of the nature of his job, he often has to work alone, so the langurs are his friends, helping him and his colleagues not feel lonely.
"Those who come with us for the first time enjoy it. But in fact, the work is very hard and stressful. Sometimes the boat stalls in the hot sun for hours, and sometimes it falls into the water. Phones and belongings fall into the sea like it's a daily occurrence," Mr. Luan confided.
Through many scientific and meticulous counting methods, conservation project staff have relatively accurately determined that the Cat Ba langur population currently has 76 individuals, an increase of 19 compared to 5 years ago.
A baby langur with unique yellow fur in its mother's arms. Photo: Neahga Leonard
In the past, Cat Ba used to have thousands of langurs. However, the habit of living off the forest, hunting animals in the past of the people and the increase in population on the island has affected and seriously reduced this population.
To prevent the extinction of the Cat Ba langur, in 2000, the Muenster Zoo and the Zoological Society for the Conservation of Species and Populations (ZGAP) of Germany funded and implemented a conservation project. At that time, there were only about 50 left. Since 2019, the Leipzig Zoo has been responsible for funding and managing the project.
Over the years, the project, together with Cat Ba National Park and local people, has tried to minimize human impacts to ensure the growth and avoid the risk of extinction of the langur species.
However, Mr. Neahga Leonard, Director of the Cat Ba Langur Conservation Project, said that the langur population is still very "fragile" because the population is small and fragmented, disturbed by humans. Langurs living on Cat Ba Island have been in a special protection area since 2006, but are under "continuous and most frequent attack" by increasing numbers of tourists while tourism management is weak.
The increase in the Cat Ba langur population is about 3% per year on average.
"The cruise ships, along with the noise and pollution, create extreme stress for the langurs here," said Neahga Leonard, adding that the project has recorded many langurs abandoning their sleeping caves and safe living areas because of human noise.
Statistics from the People's Committee of Cat Hai district show that in 2022, there were more than 2.3 million visitors to Cat Ba island. In 2020, there were 1.5 million visitors and in 2019, there were more than 2.8 million visitors.
Le Tan
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