Bonairean Bats
Bonaire has the great good-fortune to have a total of 8 species of Bats that call this island their home. Photos and more information about them can be found on this page.
Molossus molossus »
(commonly known as the Pallas' mastiff bat or velvety freetailed bat. Photo: BCI)The body and head of this bat is together 5 to 10 centimetres (2-4 inch). The animal weights 10 to 30 grams (0.4-1 ounce). One of the most obvious characteristics is the tail. It extends beyond the edge of the tail membrane. Also, it can be quite long, ranging from 2 to 7 centimetres (1-3 inch).
The bats can rest horizontally. They do not hang, but clutch to the wall with their feet and wing claws. If disturbed, they tend to scurry to a safer place instead of flying away.
These bats can be frequently found in roofs, attics and in bat houses. They leave their resting place early in the evening, often before sunset. Then they start catching insects.
This kind of bat can be found from Mexico to Paraguay and in the West Indies.
Sometimes the presence of these bats under a roof may bother the human occupants. The worst thing to do is to fumigate. This will cause a lot of dead bats, followed by a terrible smell of decomposing bats. Much better is to contact a specialist.
Leptonycteris curasoae »
(also known as the lesser-long nosed bat. Photo: BCI)Together with the long-tongued bat (Glossophaga longirostris) and the small leaf-nosed bat (Ametrida centurio), the long-nosed bat is member of the Phillostomidae (leafnosed bats). It has a small leaf-like thing on his nose.
It is just a bit larger than the very similar long-tongued bat. The head and body are about 8 cm (3 inch) long, and the bat weights about 18 to 30 gram (0.6-1 ounce). There is hardly any tail visible. For human ears the bats can be quite noisy, inside the caves as well as pollinating cacti.
The bats that we found dead weighted between 12.5 and 14 gram and had a few skin parasites. We determined the causes of death being mostly collision with a rotating fan. Once a bat was killed by colliding with a car.
On Curaçao, and probably on Bonaire as well, young bats are born in the period of June to August. This period corresponds with the peak in flower production of the two main food supplying plants, the yatu and the kadushi. Thus when there is most food available, and the best chances for the young to survive, the young are born and raised.
Like the long-tongued bat it prefers nectar, pollen and fruit for diner. The long-nosed bat is specialized in pollinating the so-called kadushi (Subpilocereus repandus), a type of columnar cacti. They also consume nectar and pollen of for instance the agave (Agave spp.), the kalbas (Crescentia cujete), kapok (Ceiba pentandra) and banana plants (Musa spp.).
The relation of this kind of bat with columnar cacti is just remarkable. It's a relationship of interdependence. In other words, both are dependent on each other for survival. When there are no bats present, the cacti will hardly or not set fruit, thus be limited in their survival. The reverse is also true. Without cacti the survival of the bats will be against all odds. The way bats and cacti got so interdependent, is called in biological terms "coevolution".
The long-nosed bats are found in the most remote, quiet and dark parts of caves. Here they can be found in quite big numbers. Usually, these bats are closely packed together. Probably because they need each others body warmth. Because these bats are so susceptible to disturbance, it is for their survival of utmost importance to be careful with these spots.
Only 3 places are known on Bonaire where these bats dwell. Because these caves are not always near the food resources, it is very handy that the bats can fly distances of over 20 kilometres (12 miles).The bats can be found in Mexico and Central America, in Venezuela and on the ABC-islands, Aruba, Bonaire and Curaçao. It is not known yet if these bats can cross the distance Bonaire-Venezuela, which is about 80 kilometres or 50 miles.
Glossophaga longirostris »
(common long-tongued bat. Photo: Ellen Muller)This is a funny little bat that we encounter in many caves on Bonaire, always in groups of small numbers ranging from 1 to 20. Usually you find them close to the entrance, in the twilight zone where it is not yet completely dark. And if you are very carefull and quiet, you can approach them closely without disturbing them.
The lenght of the body including the head is only about 5 cm (2 inch). The tail is 7 mm (0.3 inch). And in total it weights about 10 grams (0.4 ounce). The two female Bonairean bats we weighted were a little heavier: 12.5 and 14 grams (0.4-0.5 ounce) respectively.
On the picture on the right (made by BAT member Mary) you can see one of its diagnostic features: the leaf on the nose. This makes it a member of the family of leaf-nosed bats (Phillostomidae), which also includes the long-nosed bat (Leptonycteris curasoae). Distinction between the long-nosed and the long-tongued bat is quite difficult. The best way is by looking at the tail-skin, which is clearly smaller in the Leptonycteris. To the Phillostomidae-family many other bats belong, such as the small leaf-nosed bat (Ametrida centurio) and even the vampire bat.
This long-tongued bat is not at all interested in blood. It is, however, very fond of nectar, pollen and fruit. It is even specialized in pollinating one of the three species of columnar cacti on Bonaire, the so-called yatu (Stenocereus griseus). Like the long-nosed bat it likes the flowers of the kapok tree, the banana plants and the calebash. To reach the nectar in the flower, it uses its huge tongue. This can be 7 cm long! That's why it got its name.
Together with the long-nosed bat, this bat and the columnar cacti are interdependent. This means without cacti no bats, and without bats no cacti. When a bat visits a cactus flower, a cactus fruit can be set. Most cacti flower and set fruits in the dry season, thus producing food for other animals (like lora, prikichi and iguana) as well.
The first time we found female bats with grown up babies on Bonaire was July 2001. There are also signs that these bats will move to another place (i.e. cave) for the reproduction period. Research continues....
Mormoops megalophylla »
(also known as the Peter's Ghost-faced bat. Photo's: BCI)The face of this bat is very remarkable, as you can clearly see in the picture. It is formed by the complex folding of the skin.
These bats weight about 12 to 20 gram (0.4-0.7 ounce). The head and body are 6 to 8 centimetres (2.5-3 inch).
They are insect eating bats, catching their prey by flying low above water and ground. Sometimes you can hear a typical rattling sound that the bat makes by chattering his jaws.
The bats start flying about 10 minutes before it is completely dark. But they are most active around 23.00hr.On Curaçao, and probably on Bonaire, the period of the newborn young is around October. This coincides with the start of the rainy season, the period of the highest concentrations of insects.
They live in caves. Here the bat is often seen hanging on both legs instead of just one leg like most bat species. The bats form colonies, but they hang separately. On Bonaire so far only one cave is known to have a population of the ghost-faced bat, in a limited number of about 50 individuals. In the world, there is a colony known of 500.000 individuals. The bats can be found along the Caribbean coast of South America.
Probably this bat is an endemic subspecies.
Noctilio leporinus »
(sometimes referred to as the fisherman bat or greater bulldog bat. Photo: BCI)This is the largest bat that can be found on Bonaire. The head and body are together 9 to 13 centimetres (4-5 inch) and the bat weights 60 to 80 grams (2-3 ounce). It has a very clear white line across its back.
The most remarkable feature of this bat is his ability to catch little fish. When these fish are close to the surface, they make a little rippling. The bats see, or better said hear, this rippling with their echo-location. Then he catches the fish with his long feet and toes. The bats forage in both fresh and seawater.
Other bat species also tip the water, but don't make the mistake to call them fisherman bats. Those bats need to drink and tip the water with their mouth.
Their jaws are more or less elastic and can be opened widely. This is very useful when eating a fish.
Caves where the fisherman bats are dwelling, can be recognized by the strong musky smell. Those caves can be close to the sea, but also inlands.
The bat used to be seen often on the leeward side of the island, above the sea. But after hurricane Lenny struck the island, no sightings of the bats are recorded yet. There are positive indications of his presence however.
The bats are active around dusk and at night. But also they have been seen late in the afternoon, in the middle of a group of pelicans. They are then skimming the surface, zigzagging, in small groups or individually.
Natalus tumidirotris »
(the funnel eared bat)The ears of this bat are very pronounced. They are formed like a funnel, hence its name. If you look at the bat's face you hardly see the eyes. They are well hidden under the big ears. The bat itself is quite small, the head and body of is 3 to 5 centimetres (1-2 inch).
The bat has with a sweet looking face, a white belly and a big tail membrane. With this membrane it catches insects. It is flying like a butterfly, fluttering. Then it makes an audible but very soft sound, like a sewing machine.
We found 3 bats of this species that were killed by a ceiling fan rotating overnight. Two males and one female. We weighted them: only 10 gram, so that is 3.3 gram (0.1 ounce) each! This is about the weight of 3 raisins.
On Curaçao, and probably on Bonaire, the period of the newborn young is around October. This coincides with the start of the rainy season, when there is the highest concentration of insects to be found.
They can be found in caves individually or in big groups up to 1000 animals. On Bonaire, 2 caves with funnel-eared bats are found. But they are in low numbers, about 100 to 150 all together. There used to be a big colony in a cave that collapsed due to building practices.
The species Natalus tumidirostris can also be found in Venezuela and the Guyanas. Probably the subspecies is endemic to Bonaire.
Photo credit: University of Alaska Fairbanks
Myotis nesopolus
(little brown bat)On first glance, this bat is very similar to the funnel-eared bat. It is small, the head and body are together 3 to 5 centimetres (1-2 inch). It weights 4 to 7 grams (0.14-0.3 ounce). And it has a big tail membrane, and that is on purpose. They use it as a dip net to catch insects.
These bats fly with fast wing beats and many dives and turns to catch their prey.Myotis-bats can be found in caves, in tree cavities, rock crevices and in buildings. They normally rest in groups. The Myotis family is a big family. It comprises 3 genera and 97 species, with a wide distribution over the world.
Our species, M. nesopolus, can be found in Venezuela and the islands nearby. The family of these bats comprises 3 genera and 97 species.
On Bonaire, a bat has recently been encountered dead and another one has been caught during research. It has not been found in caves yet.
So far we don't have pictures of this species. But that will change in the future, we hope. In the meantime enjoy the splendid flying bats (source: CCCOE).
Ametrida centurio »
(small leaf-nosed bat)This bat is only once seen and caught on Bonaire, when it entered a house in 1958. It is also found in Venezuela and Trinidad. Some time ago the bat caught on Bonaire was thought to be a different species, A. minor. Research revealed that the bats all belong to one species, A. centurio.
Characteristics of this bat: the lenght of the head and body is about 4 cm (2 inch), and the bat has no tail. It weights about 8 gram (0.3 ounce). And being family of the leaf-nosed bats, it has a fine little leaf on the nose.
The diet of this bat is unknown, but will probably be fruits.
Photo credit: University of Alaska Fairbanks