March 22, 2025

Did you know that Thailand is the only country in the world, alongside Myanmar, to be home to the smallest mammal on Earth? Meet the bumblebee bat, also called Kitti's hog-nosed bat (or Kitti's pig-nosed bat). This miniature creature, no larger than a thumb, is found primarily in Kanchanaburi Province, in the Khwae Noi River basin in central-western Thailand. Here's what you need to know about it...

What is the Bumblebee Bat?

The bumblebee bat, scientifically known as Craseonycteris thonglongyai, is a species of bat belonging to the order Chiroptera. It is the smallest bat species in the world and the tiniest mammal on the planet. Its name, in fact, stems from its diminutive size—it resembles a flying insect.

As Soisook explains, the mammal curator at the Princess Maha Chakri Sirindhorn National Museum of Nature in Thailand, these creatures are so small that they "look just like black dots on cave walls; you might not realize they're actually bats unless you went to look more closely."

It is also nicknamed Kitti's hog-nosed bat (or Kitti's pig-nosed bat), a name inspired by the zoologist who discovered the species in 1973 in a limestone cave within Thailand's Sai Yok National Park: Thai zoologist Kitti Thonglongya. The term "pig-nosed" simply refers to its snout, which resembles that of a small pig.

Where is the Bumblebee Bat Found in the World?

The bumblebee bat is a cave-dwelling species, like other members of the Chiroptera order. Its distribution is found exclusively in Thailand and Myanmar, making it an exceptionally rare species. According to studies conducted between 1997 and 2008, Kitti's hog-nosed bat has been recorded in only 44 caves in western Thailand and 5 caves in Myanmar.

What Does the Bumblebee Bat Look Like?

The bumblebee bat is considered the world's smallest mammal due to its size: it measures just 2.9 to 3.3 cm in length and weighs approximately 2 grams. To put this in perspective, it's smaller than a thumb! However, it is not the lightest mammal in the animal kingdom. By comparison, the Etruscan shrew, a European insectivore, measures 5.4 to 8.4 cm but weighs only 1.8 grams.

Beyond its diminutive dimensions, Kitti's hog-nosed bat is characterized by a small head featuring tiny eyes largely concealed by fur and ears wider than its head. It has a swollen snout with fine, vertical nostrils whose shape resembles a pig's nose.

Its fur is brown, reddish, or gray with paler undersides. It has broad wings with a wingspan of 7.5 cm, enabling it to glide and hover in flight. It has the distinctive feature of lacking an apparent tail and calcar (a spur-like cartilage found in most bats).

What is its Lifestyle Like?

The bumblebee bat spends most of its time sleeping, suspended from the ceilings of caves and caverns by its claws. This nocturnal animal emerges only twice daily: approximately 20 minutes at dawn and 30 minutes in the evening after sunset. These brief forays allow it to feed.

To hunt insects, Kitti's pig-nosed bat uses echolocation. This technique, comparable to sonar, involves emitting sounds (often very high-pitched and inaudible to humans) and listening to their echoes to navigate its environment and locate prey.

But what does the bumblebee bat eat? Its preferred diet consists of small flies (such as Chloropidae, Agromyzidae, and Anthomyiidae), hymenopterans, and psocopterans. It captures them primarily in flight by plucking them from the air with its feet. It also occasionally consumes fruit, giving it a role as a pollinator and seed disperser. In any case, it is renowned for regulating populations of pest insects.

The bumblebee bat typically lives in colonies of varying sizes. Some colonies comprise as few as 15 individuals while others reach 100 or more. After breeding, females give birth to only one young per year, typically in April.

Is the Bumblebee Bat Threatened?

As a rare species found in only two countries worldwide, the bumblebee bat was classified as an endangered species on the IUCN Red List for nearly 12 years. In 2008, following the discovery of new populations at the Thailand-Myanmar border, it was reclassified and has since been listed as a near-threatened species.

Nevertheless, the species remains vulnerable and is particularly sensitive to environmental disturbances. Among the threats facing the bumblebee bat are:

• Habitat degradation: deforestation, urbanization, quarrying, agriculture, and guano collection significantly affect the bats' resting and feeding areas;
• Human activities: according to ecologists, human presence in caves (such as monks using caves for meditation and unregulated tourist visits) can have a severe impact on the species by disrupting their lifestyle;
• Pesticide use: pesticides used to control pest insects reduce the food sources available to bats;
• Climate change.

In Thailand, the bumblebee bat is legally protected. Nature reserves and population monitoring programs have been established to ensure the species' survival.

Where Can You See the Bumblebee Bat in Thailand?

Wondering where you can find Kitti's pig-nosed bat in Thailand? The bumblebee bat population is restricted to a single region: Kanchanaburi Province, specifically in caves and caverns around the Khwae Noi River drainage basin. It is found primarily in caves within Sai Yok National Park and occasionally in Erawan National Park.

Guided excursions allow tourists to attempt viewing bumblebee bats up close. These include Khang Khao Cave, a limestone grotto situated just 2 km from Sai Yok National Park's visitor center, and Lawa Cave.

How to see the bumblebee bats without disturbing them?

As mentioned earlier, human presence can disrupt their balance. Therefore, we recommend selecting an operator committed to animal ethics. Furthermore, it is strongly advised to remain outside the caves to avoid disturbing them.

The ideal approach? Plan an outing at dawn or sunset and stay about ten meters from the cave entrance to watch them emerge and return during their feeding forays. Avoid sudden movements, loud noise, and do not use camera flashes.

Also, try to avoid visits during April and May, which correspond to breeding seasons.

Are Thai and Burmese Populations Undergoing Speciation?

Recent research suggests that bumblebee bat populations in Myanmar and Thailand may be two distinct species, or at least undergoing speciation—an evolutionary process by which new living species form from common ancestors. Although data is lacking to confirm this phenomenon, a study examining echolocation call frequencies revealed notable differences between the two populations.

As Soisook explains: "We cannot designate them as different species, but at least, we know they are currently in the process of speciation. This offers scientists a fascinating opportunity: they might be able to study a mammal splitting into two species, or subspecies. But for that to happen, ecologists must, of course, ensure that neither of these two populations disappears."

For further reading on the same topic, discover also:

• What animals can you see in Thailand?
• The must-do activities in Kanchanaburi

Florine Dergelet

Florine Dergelet

A web writer for over 10 years, Florine Dergelet is a traveler driven by the desire to discover the world with an open heart. Each of her articles is an invitation to slow down, to listen, to understand. For her, travel is not about ticking countries off a map, but about building connections—often invisible but always powerful—with places, peoples, and all creatures of the animal kingdom. Her motto? Advise travelers with ethics, raise their awareness of animal welfare, respect for cultures, and the importance of humble and sustainable tourism. Because the most beautiful memories are often born far from the spotlight, in the shadow of a trail, at the edge of a conversation, or in the quiet breath of a world we finally take time to listen to…