Caves, like the Hato caves: bat condominiums

This post is also available in: Dutch.

For most people caves and bats are virtually synonymous. And with good reason. A significant number of bat species prefer caves to live in. Those humid, dark rooms are perfect hiding places for the dangers of daytime. What’s more, caves even out temperature fluctuations, and in colder climates provide the perfect place for hibernation.

A Long-nosed bat visiting a Kadushi flower

At least 8 species of bat have turned Curaçao into their home. Some even went as far as to adapt themselves in such way, that they now are considered endemic. These 8 species belong to three groups, based on their food preferences. Some of them are specialized in catching insects, which they’ll locate with their highly sensitive echo location system. They emit very high pitched sounds, higher than humans can perceive. When a bug flies by, some of these signals bounce off the insect for the bat to capture. It processes them instantaneously, and aims for the insect which generally ends up in the bat’s stomach. Only the real lucky ones survive. Imagine, one of these little winged mammals is able to devour up to 600 mosquitoes in one hour. Much better than insecticides, if you’d ask me!
One bat species on the Island feeds on fish. The Bulldog bat (Noctilio leporinus) is able to detect the minute vibrations caused by fish sleeping just below the water surface. With its long hind toes, and the membrane in between its hind legs it scoops unlucky, but tasty fish from the sea.

Below are images of some of these species. The image on the far left is of a group of Mormoops megalophylla intermedia (endemic!). These bats have a bizarre facial structure which is specially adapted to guide the ‘sonar waves’ to their huge ears. They do (still) have eyes, and are able to see (the lore that bats are blind is just not true!), but they will not use this ability much.
The tiny fur ball in the middle is a Natalus tumidirostris. Also insectivorous. On the right a picture of a Noctilio, much bigger in size. Beautiful animals.

The species of the third group are extremely important for the survival of the terrestrial ecology in its entirety. The nectarivorous bats, the ones living on nectar from flowers and also fruits, have been proven to be the main pollinators of the columnar cacti on the Island. And these cacti are the only plant species that produce flowers and fruits during the dry season, which provide the survival ration of lots of animals, like lizards, iguanas, fruit-eating birds and so on. Hence, without bats there would be no cactus reproduction. And if bats would be eradicated, ecological collapse is eminent.

The two species that provide these indispensable services are the Long-nosed bat (Leptonycteris nivalis curasoae), and the Long-tongued bat (Glossophaga elongata). The first one, on the left in the picture below, is endemic for Curaçao and Bonaire. On Curaçao, we have counted about 1400 individuals of this species, and on Bonaire there occurs about the same number. These are scaringly small population sizes if you would compare that to the 3 million or so individuals in caves in Mexico and the United States. The Glossophaga, on the right, is more common, also in other Islands in the Caribbean and northern South America.

No wonder they call them Long-tongued bats!

The Glossophaga is the species that you’ll encounter in the Hato caves. Contrary to most other species on the Island, the Long-tongued bats are not that afraid of humans. They are even quite inquisitive. During daytime they lock their toes around small imperfections on the ceiling of the caves, hence spending half of their lives upside down. During the night they leave the caves to perform their majestic part in the cycle of life.

 

 

 

 

 

Leon Pors

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