The mysterious mouse

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A baby house-mouse after an undesired bath in the turtle tub.

A baby house-mouse after an undesired bath in the turtle tub.

The species of Homo sapiens, also known as the thinking human, has spread over the surface of the earth using all kinds of inventions. By leg power, boats and, especially the last couple of decades, by airplanes. There is almost no place left on terrestrial earth which has not been visited one time or another by a human individual. The unexplored en unvisited places are becoming scarcer by the day.
The big trouble is, Homo sapiens has the persistent tendency to bring along stowaways. It doesn’t matter whether these are species of flora which are brought along consciously or unconsciously as seeds, or species of fauna which have adapted their lifestyle to such an extent that all life processes take place in the immediate vicinity of man. Mankind almost never arrives alone!


History of mankind is filled with examples of animals which were intentionally or unintentionally brought along on world travels and were introduced on locations where they have not existed before. The consequences can be disastrous for the ecology of the new countries where these stowaways end up. Who doesn’t know the example of the Dodo on the Pacific island of Mauritius? Besides the fact that humans ate this bird, even though it was known to be disgusting to eat, introductions of invasive species of rats and mice made sure this bird went extinct. These rodents not only ate the eggs but also stole the young birds. The Dodo went extinct in a very short amount of time, and many more species of birds suffered the same fate on other islands, which were visited by the Europeans as well.

House mice… world citizens

The house-mouse, the species of mouse which motivate many people to start screaming when it jumps out of a closet or wanders around in the house, and can usually be found in the direct environment of humankind, has its origins in Eurasia, but has now spread out all over the world, thanks to human introductions. The animals live in warehouses, barns and other places where they can find enough food, often also in large fields of agricultural areas.
The house-mouse (Mus musculus) is omnivorous. This entails that food consists of plant materials such as grains, seeds, fruits and leafs, as well as animal based foods such as worms and insects. Eggs of smaller species of birds are also in danger when this mouse is around.
The distribution stories of the Mus musculus is quite diverse in relation to locations. In the United States for example, the reigning theory is that the animals were introduced as early as the American Revolution. On Curacao presumable the species was introduced when the first European ships reached the island.
In historical books there are often references to the house-mouse as being a pest. On plantations where sorghum was cultivated, the mice developed into a big nuisance as they ate large quantities of grains. Warehouses would often fall victim to large quantities of mice which wreaked havoc on food supplies. People still hate mice in these modern times for the damage they cause to agricultural areas, in warehouses where food is stored, our kitchen cabinets because they nibble on everything in search for food and nesting materials. But also because they pie en poop on everything and like to build their nests in between your photo albums if you are not careful.
Humankind has become quit driven in the invention of all kinds of eradication tools to try to withdraw the animals from living areas, something which, up to this moment has not been very successful.


The original specimen of the Hummelinck's vesper mouse in Naturalis.

The original specimen of the Hummelinck’s vesper mouse in Naturalis.

Most people on our island think of the house-mouse when the word mouse is mentioned. Not many people know however that Curaçao has a real native species of mouse, which almost never lives in the direct vicinity of humans. This mysterious small species of mouse with white paws is the Hummelinck’s vesper mouse (Calomys hummelincki).

The Hummelinck’s vesper mouse

The Hummelinck’s vesper mouse was found on Curacao for the first time at the St. Thomas College, Plantage Jongbloed in 1945. According to the book ‘Zoogdieren van de Nederlandse Antillen’ by Pieter Wagenaar Hummelinck, some remains were found in the owl pallets of Barn Owls in the neighbourhood of Savonet. On Aruba the first individual was found by Pieter Wagenaar Hummelinck in 1930 at Seroe Blanco and Baranca Corá.
Nobody knew it was a new and different species, and scientists only discovered that it was indeed different from the Mus musculus when they started observing the specimens a little better. Then they discovered that the Hummelinck’s vesper mouse was much smaller than the common mouse (6 cm instead of the 8cm of length of the house mouse) and had other features as well which distinguished it from the common mouse.
Dwerghamster_Wikipedia-CommonsThe Hummelinck’s vesper mouse  has a shorter tail in relation to its body size in comparison to the house mouse. The tail is not only shorter than its body length, it also has a white tuft at the very end of its tail. Its back feet are also smaller and are densely covered with white hair. The animal itself has a light brown color with yellowish sides.

A mysterious animal

The Hummelinck’s vesper mouse has been described officially for the islands of Aruba and Curaçao, but I have no idea whatsoever if the species still exists on the island. Most people will not go more than the usual distance when seeing a mouse, and as such it can well be that animals in rural areas are identified as being normal house mice when in reality they are Hummelinck’s vesper mice. Usually the animals will not live in areas where humans live but might eat grains like sorghum.

Hummelinck's vesper mouse as drawn in the book 'Zoogdieren van de Nederlandse Antillen' by Pieter Wagenaar Hummelinck

Hummelinck’s vesper mouse as drawn in the book ‘Zoogdieren van de Nederlandse Antillen’ by Pieter Wagenaar Hummelinck

A couple of years ago Curaçao was the host of a researcher who came to the island especially to search for the mysterious rodent. After spending weeks in the field, and catching dozens of mice, she still had not found the Hummelinck’s vesper mouse. She went back to her country of origin with empty hands. It might be possible that the animal still exists on the island, and lives in places where humans, with their mouse traps, mouse venom and cats, do not visit. But we have no proof for this conclusion.
A mysterious and small Curaçaoan. I sincerely hope to have the chance to encounter this animal at least once. It would be really dramatic to include this species on the already  unacceptably large list of species of flora and fauna which became extinct because of human kind.



About Michelle da Costa Gomez