Stephens's kangaroo rat facts for kids
Quick facts for kids Stephens's kangaroo rat |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Dipodomys
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| Species: |
stephensi
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The Stephens's kangaroo rat (Dipodomys stephensi) is a small rodent that lives only in Southern California in the United States. It is mostly found in western Riverside County. This special rat is named after an American animal expert, Frank Stephens, who lived a long time ago.
This kangaroo rat lives in open, grassy areas called temperate grasslands. Sadly, many of these natural homes have been destroyed or changed for farms and buildings. Because of this, the Stephens's kangaroo rat is now listed as an endangered species. This means it needs special protection to survive. It lives near another type of kangaroo rat, the agile kangaroo rat. But the Stephens's kangaroo rat likes areas with fewer bushes and rocky soil. The agile kangaroo rat prefers places with more dense bushes.
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What Does It Look Like?
The Stephens's kangaroo rat is a medium-sized rodent in its group, called Dipodomys. It is about 27.7 to 30 centimeters (11 to 12 inches) long from its nose to the tip of its tail. It usually weighs around 67 grams (about 2.4 ounces). Its tail is quite long, measuring about 16.4 to 18 centimeters (6.5 to 7 inches). This means its tail is about 1.5 times longer than its body!
Its fur has two colors. The top part of its body is tan to dark brown. Its belly and underside are white. The bottoms of its back feet are a bit dark. It also has some white hairs on the tufts of its tail. You can see white stripes running along the top and bottom of its tail too.
Where Do They Live?
Stephens's kangaroo rats used to live in a few specific areas in southern California. But because of new buildings and homes, their natural living spaces have shrunk. Now, you can only find them in special nature reserves. These reserves are in places like San Jacinto Valley, San Bernardino, and northwestern San Diego counties in California.
Many of the places where they live are surrounded by roads. Busy, paved roads can be dangerous for them because of cars. However, these kangaroo rats have been seen living and even making homes along dirt roadsides. This might be because they like the type of habitat found there.
They prefer open areas with not too much plant cover, about 15% cover. They like annual grasslands with only a few low sagebrush plants. They also like areas that have been kept open by fires, grazing animals, or farming. It is important for them to have gravelly soil that is not too hard. This is because they need to dig tunnels and burrows in the ground. These tunnels are their homes and where they store food.
What Do They Eat and How Do They Find Food?
Since they live in open areas, these rats create clear paths or trails on the ground. They use these trails to move easily from one food source to another. These trails also help them stay safe while looking for food. If a predator appears, they can quickly run along these clear paths straight back to their burrow.
Even though they use trails to escape predators on the ground, they still need to watch out for birds of prey from the sky. To avoid these aerial predators, they often look for seeds under the bushes that are still standing. Seeds are the main part of their diet, which means they are "granivorous" (seed-eaters).
Scientists have studied the stomachs of these kangaroo rats. They found that their diets mostly include seeds from plants like red brome (Bromus rubens), common Mediterranean grass (Schismus barbatus), and red-stemmed filaree (Erodium cicutarium). All of these plants were brought to North America from other places. They also eat some insects like ants, chewing lice, and darkling beetles, but not as much as seeds.
How Do They Help Their Environment?
Stephens's kangaroo rats have a big impact on their environment, almost like a "keystone" species. Here are some ways they help:
- Digging Burrows: When they dig their tunnels, they help the soil become healthier. The soil gets more nutrients, and water can soak into the ground better. This leads to more types of plants growing in the area.
- Burying Seeds: They often bury seeds to hide them and save them for later. This is called "seed caching." Sometimes, they don't find all the seeds they buried. These forgotten seeds can then sprout and grow. This helps create a greater variety of plants around their burrows.
- Controlling Invasive Plants: There is an invasive plant called Erodium that can take over and push out native plants. The Stephens's kangaroo rat helps control this plant by eating its seeds. This helps keep the natural plant diversity in their habitat.
- Clearing Patches: These kangaroo rats clear patches of ground by removing some plants. This helps keep the environment in a "seral stage," which means it stays open and grassy. This also helps keep down the number of other rodents that eat seeds. This gives other plants a better chance to grow and develop fully.
How Their Populations Are Doing
Because the groups of Stephens's kangaroo rats are spread out, they have become separated from each other. This means they don't mix and share genes as much as they used to. For example, one type of genetic marker, called haplotype A, was found in two groups. But it was not found in groups that lived further away. This shows that there is less "gene flow" or genetic mixing between different groups of these kangaroo rats.
Another genetic marker, haplotype CC, is found in many places. However, it is not spread randomly. Haplotype CC is mostly found in the southern areas, with very little in the northern and central regions. This high amount of haplotype CC in the south suggests that a "population bottleneck" happened there. This means the southern population likely grew back from a very small group of rats. This makes sense because they live in a valley that is disconnected from the central and northern populations.
