Long-whiskered rice rat facts for kids
Quick facts for kids Long-whiskered rice rat |
|
|---|---|
 |
|
| Skull from Cerro Azul, Panama, seen from above | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Transandinomys
|
| Species: |
bolivaris
|
 |
|
| Distribution of Transandinomys bolivaris in southern Central and northwestern South America | |
| Synonyms | |
|
|
The Transandinomys bolivaris, also known as the long-whiskered rice rat, is a type of rodent (like a mouse or rat) that belongs to the family called Cricetidae. You can find it in wet forests from Honduras all the way to western Ecuador. It lives in areas up to about 1,800 meters (5,900 feet) above sea level.
This animal was first described in 1901. Over the years, it has had six different scientific names! For a long time, it was known as Oryzomys bombycinus. But in 2006, scientists moved it to a new group, or genus, called Transandinomys. Now, its official name is Transandinomys bolivaris.
It's a medium-sized rice rat that stands out because of its super long vibrissae (whiskers). The whiskers above its eyes can be up to 50 millimeters (2 inches) long! Its fur is soft and thick, usually dark brown on top and light gray underneath. Young rats have even darker fur. This rat has long feet, and its tail is about the same length as its head and body. The skull is narrow, with a wide area between the eyes. This species usually lives on the ground. Even though it's not seen very often, scientists believe its conservation status is secure, meaning it's not currently in danger of disappearing.
Contents
How Scientists Classify This Rat
In 1901, a scientist named Joel Asaph Allen described four new types of rice rats. Three of these were from Ecuador, and he gave them names like Oryzomys bolivaris, Oryzomys castaneus, and Oryzomys rivularis. He noticed small differences in their color, size, and tail length.
Later, in 1912, another scientist, Edward Alphonso Goldman, described a similar rat from Panama and called it Oryzomys bombycinus. He thought it was related to other rice rats. Over the years, more scientists studied these rats, and some thought these different names might actually be for the same animal.
It wasn't until 1998 that scientists, led by Guy Musser, finally confirmed that all these different names—bolivaris, castaneus, rivularis, bombycinus, alleni, and orinus—were all for the same species! They decided to use the name Oryzomys bolivaris for it.
In 2006, scientists used DNA and body features to study how different rice rats are related. They found that many species in the old Oryzomys group needed to be moved to new groups. That's when Oryzomys bolivaris was moved into the new genus called Transandinomys. This new group also includes another similar rat, Transandinomys talamancae. The main thing these two rats share is their very long whiskers above their eyes.
This rat is often called the "long-whiskered rice rat." Other names have been used too, like "Long-Haired Rice Rat" or "Bolivar Rice Rat."
Physical Features
The Transandinomys bolivaris is a medium-sized rice rat. Its most noticeable feature is its very long whiskers above its eyes, which can be over 50 mm (2 inches) long. These whiskers are so long they reach past its ears when laid back! Another similar rat, T. talamancae, also has long whiskers, but not as long as the T. bolivaris. The whiskers above its mouth are also long. Most of its whiskers are dark, but the tips are clear.
Its fur is soft, thick, and dense. On its back, it's dark brown to gray, becoming blacker in the middle and yellowish-brown on the sides. The fur on its belly is a different color; it's dark gray at the bottom of the hairs and white at the tips, making the belly look grayish-white. Young rats have darker, finer, and softer fur.
The tail looks bare and is usually about the same length as its head and body, or a little shorter. Its color can vary, but it's often dark brown on top and lighter brown or white underneath. The scales on its tail are smaller than those on T. talamancae.
Its front legs are dark gray. Its front feet are light-colored, and white hairs surround its claws. The rat has long, narrow hindfeet, which are longer than those of T. talamancae. The three middle toes are much longer than the two outer ones. There are six pads on the bottom of its feet. The top and sides of its hindfeet are white and look bare, though they have short, white hairs. Long, white or gray hairs surround its short, light-colored claws.
Here are some average measurements for the Transandinomys bolivaris:
| Region | n | Head and body | Tail | Hindfoot |
|---|---|---|---|---|
| Nicaragua | 5 | 108.2 (99–119) | 115.2 (99–126) | 28.8 (27–32) |
| Costa Rica, western Panama |
9–13 | 118.7 (103–134) | 113.2 (96–125) | 30.3 (27–33) |
| Central Panama | 13–15 | 120.7 (111–140) | 120.8 (111–130) | 30.0 (27–33) |
| Eastern Panama | 5 | 116.8 (107–125) | 117.6 (109–126) | 28.0 (25–29) |
| Colombia | 8 | 127.4 (115–141) | 121.3 (100–135) | 30.5 (29–32) |
| Ecuador | 8–9 | 119.4 (111–133) | 114.8 (100–127) | 29.7 (28–32) |
| Measurements are in millimeters and in the form "average (minimum–maximum)". | ||||
Its head and body length is usually between 100 to 140 mm (3.9 to 5.5 inches). Its tail is 90 to 130 mm (3.5 to 5.1 inches) long. Its hindfoot is 27 to 35 mm (1.1 to 1.4 inches) long, and its ear is 16 to 21 mm (0.6 to 0.8 inches) long. It weighs between 39 to 75 grams (1.4 to 2.6 ounces). Female rats have four pairs of nipples. Like most rice rats, it has 12 chest bones (thoracic vertebrae) and 7 lower back bones (lumbar vertebrae).
Skull and Teeth
The skull of the Transandinomys bolivaris is quite long. It has a long, narrow snout and a wide area between the eyes. The back part of the skull (braincase) is narrow. The cheekbones are wide and run almost parallel to each other.
The front part of the roof of its mouth has holes that don't reach its back teeth (molars). The roof of the mouth ends past the molars and has small pits. The bones that hold the inner ear are large.
The lower jaw is thick and has a long projection at the back. The front teeth (incisors) are large and smooth. Their enamel (the hard outer layer) is orange. The molars (back teeth) are low and have two rows of main bumps, with deep valleys between them. The first upper molar is wider than in T. talamancae. Each upper molar has three roots, and each lower molar has two roots.
Where It Lives and How It Behaves
The Transandinomys bolivaris is not a very common species. It lives in humid forests from northeastern Honduras, through Nicaragua, Costa Rica, and Panama, and into western Colombia and Ecuador. It can be found from sea level up to about 1,800 meters (5,900 feet) high in Ecuador. This area is known for its wet "Transandean forest." It prefers forests at middle elevations (around 600 to 900 meters or 2,000 to 3,000 feet) and often lives near water.
Not much is known about its daily life. This rat mostly lives on the ground. However, some young rats have been found climbing in plants, up to 1.5 meters (5 feet) above the ground. They are often caught "under logs, around the roots of large trees, or among rocks along streams."
Scientists have found pregnant females with four babies in Panama in June, one with two babies in Nicaragua in September, and one with four babies in Costa Rica in December. A very young rat was found in Costa Rica in March.
Conservation Status
The Transandinomys bolivaris is listed as "Least Concern" by the IUCN Red List (a list that tracks how endangered animals are). This means it's not currently in danger. It lives in a wide area and is thought to have a large population. Many of these rats live in protected areas, which helps keep them safe. However, the cutting down of forests (deforestation) could be a threat to them in the future.
