Lund's amphibious rat facts for kids
Quick facts for kids Lund's amphibious ratTemporal range: Late Pleistocene to Recent (Lujanian)
|
|
|---|---|
 |
|
| Lectotype partial cranium of L. molitor. The illustrated mandible represents a different species. | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Lundomys
|
| Species: |
molitor
|
 |
|
| Distribution of Lundomys molitor in South America. The current distribution is in red, and fossil records outside the current range are in blue. | |
| Synonyms | |
|
|
The Lundomys molitor, also known as Lund's amphibious rat or the greater marsh rat, is a special type of rat. It loves water and lives in southeastern South America.
This rat is a semiaquatic animal, meaning it spends part of its life in water. It is a large rodent with a long tail and big back feet. Its fur is long and thick.
Today, you can find L. molitor mainly in Uruguay and southern Brazil. But long ago, it lived further north in Brazil and south into Argentina. Scientists think the rats from Argentina might have been a bit different from the ones alive today.
Lundomys molitor builds its nests above the water, using reeds for support. It is not currently in danger of disappearing.
Contents
What is Lundomys molitor?
Lundomys molitor is one of the largest living rats in its group. It looks a lot like another rat called Holochilus brasiliensis. Because of this, scientists used to get them mixed up.
However, other features show that Lundomys molitor belongs to its own unique group, called Lundomys. It is part of a larger family of rodents called Cricetidae. Within this family, it belongs to a group of special water-loving rodents called Oryzomyini. This group also includes Holochilus, Noronhomys, Carletonomys, and Pseudoryzomys.
How Scientists Classified This Rat
The Lundomys molitor was first described in 1888. A Danish scientist named Herluf Winge studied rat bones found in caves in Brazil. He named it Hesperomys molitor.
Later, in 1955, an American scientist named Philip Hershkovitz found similar rats in Uruguay. He thought they were a new species and named them Holochilus magnus. He noticed they had flat-topped teeth, which was a special feature.
In 1980, another scientist, Elio Massoia, saw that Winge's Hesperomys molitor and Hershkovitz's Holochilus magnus looked very similar. He suggested they were the same species.
Finally, in 1993, American scientists Voss and Carleton studied Winge's original bones. They agreed that the two rats were the same species. They also found enough differences from other Holochilus rats to create a brand new group for it. They named this new group Lundomys, honoring Peter Wilhelm Lund, who first collected the bones. Since then, the rat has been known as Lundomys molitor.
Scientists continue to study these rats to understand their family tree. They look at features like teeth and even DNA to see how closely related different species are.
Physical Features of Lundomys molitor
Lundomys molitor is a very large rat. Its head and body are about 160 to 230 mm (6.3 to 9.1 in) long. The average length is about 193 mm (7.6 in). Its tail is even longer than its body, measuring about 195 to 255 mm (7.7 to 10.0 in).
- Tail: The tail is dark and has very little hair.
- Fur: The fur is long, thick, and soft. It is yellowish-brown on the sides, darker on top, and lighter underneath.
- Hindfeet: The back feet are large and have clear interdigital webbing, like a duck's foot. This helps it swim. It also has fringes of hair along the edges of its feet.
- Forefeet: The front feet have very long claws, which is unusual for rats in this group.
- Teeth: Its molars (back teeth) are slightly high-crowned. They have special ridges and cusps that help scientists identify them.
- Skull: The front part of its skull is wide. It has a strong cheekbone structure.
- Chromosomes: This rat has 52 chromosomes.
Where Lundomys molitor Lives
Today, Lundomys molitor lives in Uruguay and a part of southern Brazil called Rio Grande do Sul. It is not often seen, which might mean it's rare or just hard to find.
This rat prefers places with warm winters (over 12 °C (54 °F)), warm yearly temperatures (over 18 °C (64 °F)), and lots of rain (over 1,100 mm (43 in) per year). It usually lives in swamps or near streams.
Scientists have found Pleistocene fossils of L. molitor in places where it doesn't live now. For example, fossils were found far north in Minas Gerais, Brazil, and in Buenos Aires Province, Argentina. These fossil findings suggest that the climate in those areas was warm and wet long ago. Some of the Argentine fossils might even be from a slightly different type of Lundomys.
Natural History and Life Cycle
Lundomys molitor is a semiaquatic animal, meaning it spends a lot of time in the water. It is active at night and is an excellent swimmer. It is even better at swimming than its relative, Holochilus.
- Nests: It builds round nests among reeds in water up to 1.5 m (4.9 ft) deep. The nest is usually about 20 cm (8 in) above the water. The nest is made of reeds and has three layers around a central room. A ramp made of reeds connects the nest to the water.
- Diet: Scientists have found green plant material in their stomachs. This suggests that Lundomys molitor is a herbivore, meaning it eats plants.
- Reproduction: One female rat was found to be pregnant with three babies.
- Other Animals: Other rodents like Scapteromys tumidus and Holochilus brasiliensis are often found living in the same areas as Lundomys molitor.
Conservation Status
The Lundomys molitor is currently listed as "least concern" by the International Union for Conservation of Nature. This means it is not considered to be in immediate danger.
It lives in a fairly wide area, and there is no strong evidence that its numbers are decreasing. Some areas where it lives are protected. However, the destruction of its habitat (the places where it lives) could still be a threat in the future.
