Located in the southern province of Dong Nai around 150 kilometers north of HCMC, Cat Tien National Park, recognized as a world biosphere reserve by UNESCO, has become a major tourism destination.

But a relatively new form of tourism in the park, night excursions, has gained in popularity.

The one-hour trip, costing VND150,000 ($6.5) per person, allows visitors to sit on an open-top truck. Spotlights are used to observe the animals come out to feed at night. The 71,000-hectare national park is home to about 1,500 species of animals including Asian elephants, sun bears, gaur and a variety of smaller mammals.

Dinh Sy Dat, a ranger at the national park, said wildlife-watching tours attract around 10,000 visitors every year.

"The purpose of nighttime wildlife watching tours is to raise public awareness of conservation efforts and it has become a popular adventurous experience at Cat Tien National Park," he said.

However, many Vietnamese online users have pointed out that the use of spotlight would frighten the animals and amounts to harassing them in their natural habitat, disturbing their normal activities.

Cong Dinh, a VnExpress reader, said it would affect the habitat of species. These mammals always go out for food at night but if tourists keep training their flashlights on them, they would get frightened and flee.

Another reader, Nguyen Nguyen, also noted that the wildlife avoid the crowds in daytime and look for food to survive at night, but they continue to be harassed by humans. "Let them enjoy their freedom," Nguyen wrote.

"The tour is destroying the nightlife of wildlife, because they are not used to the appearance of humans (at that time)," wrote Long, another VnExpress reader.

Daniel Willcox, an expert with Save Vietnam’s Wildlife, a non-profit organization, told VnExpress International that the impacts of these night tours on animal welfare are probably not much. He said the night drives at the park happen at a certain speed and the lights are rarely shone on the animals for very long.

"None of the animals that one typically sees at night in Cat Tien show much reaction to the torchlight, other than to move off if it gets too irritating," he said.

"Night spotting is a fantastic opportunity to see wildlife that people rarely see, but people doing it should stick to trails and the main road for safety and not go into the forests at night," he said.

The Cat Tien National Park is part of the wet tropical forest complex and one of the specious natural forests remaining in Vietnam. Its worldwide importance has also been recognized.

In 2001, the park was listed by UNESCO as the 411th biosphere reserve zone in the world.