Gray rice rat facts for kids
Quick facts for kids Gray rice rat |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Eremoryzomys
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| Species: |
polius
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| Range in northern Peru | |
| Synonyms | |
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The Eremoryzomys polius, also called the gray rice rat or Marañon oryzomys, is a type of rodent. It belongs to the rice rat group, known as Oryzomyini, which is part of the Cricetidae family. This family includes many small rodents like hamsters and voles.
Scientists first found this rat in 1912. It was described in 1913 by Wilfred Osgood. At first, it was put into the Oryzomys group. But in 2006, a study showed it was different from other Oryzomys species. So, scientists gave it its own special group, called Eremoryzomys.
The gray rice rat is quite large with a long tail. It has gray fur and small ears. It lives only in a small area of central Peru, near the Marañón River. Scientists don't know much about this rat. Because of this, its conservation status is "Data Deficient". This means we need more information to know if it's in danger.
Contents
Meet the Gray Rice Rat: What It Looks Like
The Eremoryzomys polius is a big rice rat with a long tail. Its fur is gray on top and lighter underneath. The hairs on its belly are gray at the bottom and white at the tips. Its ears are short, and its tail is dark on top and light below.
Special Features of Its Feet
This rat has special patches of hair on its hindfeet. These are called ungual tufts. They are found along the edges and between its toes. This feature is quite rare among rice rats. The soles of its hindfeet also have well-developed scales.
Size and Other Details
The length of its head and body is about 138 to 164 millimeters (5.4 to 6.5 inches). Females have eight mammae, which are milk glands for feeding their young. Like most rice rats, it has 12 vertebrae in its chest area.
Skull and Bones
The front part of its skull, called the rostrum, is long and strong. The braincase, which holds the brain, is rounded. Older rats might have more bumps or ridges on their skulls. The bony palate inside its mouth is quite short. The skull also has special openings and grooves that show how blood flows to its head.
Where Does the Gray Rice Rat Live?
The Eremoryzomys polius lives in a small part of central Peru. It can be found at heights from 760 to 2100 meters (2,490 to 6,890 feet) above sea level. It prefers forests in the dry lowlands near the upper Marañón River. This area is east of the main Andes mountains.
Conservation Status and Threats
Because we don't know much about this rat, the IUCN Red List calls it "Data Deficient". This means there isn't enough information to properly assess its risk of extinction. However, its home is being destroyed to create land for cattle. This could be a big threat to the gray rice rat. It has not been found in any protected areas.
How Scientists Study This Rat
The first two gray rice rats were collected in 1912 by Wilfred Osgood and M.P. Anderson. Osgood described them in 1913. He named the species Oryzomys polius. He noted that it didn't seem closely related to any other known species.
Changing Its Scientific Name
For a long time, its relationships to other rats were unclear. Then, in 2006, a scientist named Marcelo Weksler did a big study of rice rats. He used both physical features and genetic information. His study showed that O. polius was not closely related to the Oryzomys group.
Because of this, Weksler and other scientists created a new group, or genus, for it. They called this new genus Eremoryzomys. The name Eremoryzomys comes from a Greek word meaning "lonely place." This refers to its unique and isolated home. So, its full scientific name became Eremoryzomys polius.
Relatives of the Gray Rice Rat
In 2011, a new rice rat called Drymoreomys albimaculatus was found in Brazil. Scientists now think this Brazilian rat is the closest known relative to the Eremoryzomys. This connection between a rat from the Andes and one from the Atlantic Forest is quite unusual. Most similar cases involve animals from humid forests, but the gray rice rat lives in a dry area.
Eremoryzomys is now one of about 28 groups in the Oryzomyini tribe. This tribe has over a hundred species, mostly found in South America. The Oryzomyini tribe is part of a larger group called Sigmodontinae. This group includes hundreds of species found across North and South America. Sigmodontinae is the biggest subgroup of the Cricetidae family, which also includes voles, lemmings, and hamsters.
Images for kids
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Eremoryzomys occurs in the basin of the upper Río Marañón.
See also
In Spanish: Eremoryzomys polius para niños
