Naked-tailed voalavo facts for kids
Quick facts for kids Naked-tailed voalavo |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Voalavo
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| Species: |
gymnocaudus
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| Known records of Voalavo gymnocaudus (red) and Voalavo antsahabensis (green) | |
The northern voalavo (Voalavo gymnocaudus) is a small, mouse-like animal. It is a type of rodent, which means it's related to mice and rats. This special animal lives in the Northern Highlands of Madagascar, a large island country.
Scientists first found the northern voalavo in 1994. They officially described it in 1998. It is the main species in its group, called Voalavo. Its closest relative is the eastern voalavo, which lives in a different part of Madagascar. Scientists use DNA sequencing (looking at an animal's genetic code) to understand how different animals are related. This research suggests the northern voalavo might be more closely related to another rat called Grandidier's tufted-tailed rat than to other similar species.
You can find the northern voalavo high up in the mountains, between 1,250 and 1,950 meters (about 4,100 to 6,400 feet) above sea level. It lives in wet and dry mountain forests in areas like Marojejy and Anjanaharibe-Sud. This animal is nocturnal, meaning it is active at night, and it lives alone. It mostly stays on the ground but can also climb trees. It probably eats plants. Even though it lives in a small area, the northern voalavo is not in danger. This is because its home is mostly in protected areas, and there are no big threats to it. So, it is listed as a species of least concern.
The northern voalavo is a small, mouse-like rodent. It has soft, grey fur that is a little darker on its back than on its belly. Its ears are short and round. Its long tail looks mostly bare, without a bushy end like some other rats have. It is very similar to the eastern voalavo, but they have slight differences in their body measurements. The northern voalavo's skull is delicate. It has a long, narrow front part and a narrow area between its eyes. Its teeth are also special, being relatively high-crowned. This little animal weighs between 17 and 25.5 grams (about 0.6 to 0.9 ounces).
Contents
Discovery and Family Tree
How it was Found and Named
Before the 1990s, scientists hadn't studied the rodents in the Northern Highlands of Madagascar very much. In 1994, a team explored the Anjanaharibe-Sud Reserve. This trip helped them find two new species: Grandidier's tufted-tailed rat and the northern voalavo. The northern voalavo was the first known species of its group, called Voalavo.
Two scientists, Michael Carleton and Steven Goodman, officially described both species in 1998. The name Voalavo is a general word for rodent in the Malagasy language. The second part of its name, gymnocaudus, means "naked tail." This name helps tell it apart from other similar rats that have bushy tails. In 2000, the northern voalavo was also found in the nearby Marojejy National Park.
Understanding its Relatives
Scientists use special methods, like looking at DNA, to figure out how animals are related. In 1999, a study looked at the DNA of native Malagasy rodents. The results suggested that the northern voalavo and Grandidier's tufted-tailed rat might be more closely related to each other than to other species in the Eliurus group. This means the way scientists group these animals might need to change.
However, they couldn't study the DNA of all related species, so more research was needed. Later studies in 2003 also supported the idea that the northern voalavo and Grandidier's tufted-tailed rat are close relatives.
In 2005, another species of Voalavo, the eastern voalavo, was discovered in central Madagascar. These two Voalavo species look very similar, but they have small, consistent differences. Their DNA also shows about a 10% difference. When closely related animal species have more than a 5% difference in their DNA, it can mean there are "cryptic species" – species that look almost identical but are actually distinct.
Physical Description
Outside Appearance
| Location | Number of animals | Head-body length | Tail length | Hindfoot length | Ear length | Weight |
|---|---|---|---|---|---|---|
| Anjanaharibe-Sud | 4 | 86–90 | 119–120 | 20–21 | – | 20.5–23.5 |
| Marojejy | 5 | 80–90 | 113–126 | 17–20 | 15–15 | 17.0–25.5 |
| Number of animals: How many specimens were measured. All lengths are in millimeters, and weight is in grams. |
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The northern voalavo is a small rodent that looks like a mouse. It is very similar to the eastern voalavo, but the northern voalavo usually has a longer tail. It also looks like smaller species of Eliurus rats, but its fur is darker, and it does not have a bushy tail tip.
Its fur is soft, short, and thick. It looks dark grey on most of its upper body and a bit more brownish on its sides. The hairs on its back are three colors: mostly grey, with a narrow light band and a black tip. Longer, black hairs also stick out. The fur on its belly is similar in color, but the individual hairs are grey with white tips. The hairs on its chin are all white.
The northern voalavo has long whiskers on its upper lips that can reach its ears when pressed back. Its ears are short and round. They are bare inside but covered with short brown hairs on the outside.
Its toes and feet are mostly covered with white hairs. There are small tufts of hair around the base of its claws. It has five pads on its front feet and six pads on its back feet. On its back feet, the fifth toe is almost as long as the middle three, and the first toe (like a thumb) is much shorter. The tail is longer than its head and body. It looks mostly bare, but you can see fine hairs near the tip. The tail skin is grey, with fine dark brown hairs along most of its length and white hairs near the tip.
Inside its Body: Skeleton and Teeth
The northern voalavo has a delicate and lightly built skull. The front part of its skull is narrow and fairly long, shorter than in the eastern voalavo. The cheekbones are narrow. The area between its eyes is narrow and short, without any extra ridges. The part of the skull that holds the brain also lacks these ridges.
Its teeth are also unique. The front teeth (incisors) in the upper jaw are straight and have yellow to light orange enamel. The lower incisors have fine ridges on their enamel. The rows of molars (back teeth) are longer than in the eastern voalavo. Like in Eliurus rats, the molars are high-crowned. The individual bumps on the molars have joined together into ridges. The first and second molars are similar in size, but the third molars (both upper and lower) are noticeably smaller. Each upper molar has three roots, and each lower molar has two roots.
Where it Lives and How it Behaves
The northern voalavo has only been found in two mountain areas in the Northern Highlands of Madagascar: Anjanaharibe-Sud and Marojejy. However, it might live in a wider area.
In Anjanaharibe-Sud, it has been found in wet mountain forests at 1,950 meters (about 6,400 feet) above sea level. Here, it lives alongside other native rodents and even the introduced black rat. It also lives in drier forests at about 1,300 meters (about 4,300 feet). In Marojejy, it lives in similar habitats between 1,250 and 1,875 meters (about 4,100 to 6,150 feet) high.
The northern voalavo likely spends most of its time on the ground. However, it can climb in plants. It prefers areas with many roots, where it moves through natural tunnels and paths. This animal is nocturnal, meaning it is active at night. It lives alone and probably eats fruits and seeds. It can have up to three babies at a time.
Like many animals, the northern voalavo can have tiny creatures called arthropods living on it. These include different types of mites and sucking lice. In 2007, a new species of mite was even discovered on a northern voalavo! It can also have a tiny internal parasite called Eimeria.
Conservation Status
Even though the northern voalavo lives in a small area and is not very common, scientists don't know of any major threats to it. Almost all of the places where it lives are protected areas, like national parks or reserves. Because of this, the species is listed as "Least Concern" on the IUCN Red List. This means it is not currently in danger of disappearing.
