Over time, the proportion of individuals with advantageous characteristics may increase due to their likelihood of surviving and reproducing.Natural selection is dependent on environmental conditions.Inherited characteristics affect the likelihood of an organism's survival and reproduction.Natural selection acts on the variation that exists in a population.There is variation within a population.Evolution results from selection acting upon genetic variation within a population.Information on controversies in the public arena relating to evolution.Alignment with the Next Generation Science Standards.The big issues – Pacing, diversity, complexity, and trends.Macroevolution – Evolution above the species level.Microevolution – Evolution within a population.Mechanisms: the processes of evolution – Selection, mutation, migration, and more.The history of life: looking at the patterns – Change over time and shared ancestors.An introduction to evolution: what is evolution and how does it work?.So, pocket mice here at White Sands National Park are not just an important species, but also one of many unique animals that call this park their home. Apache pocket mice aren’t the only ones to develop a white color other animals at White Sands, like insects and lizards, have done the same. Finally, it resulted in the white camouflage we see today. Over time, this natural selection caused the Apache pocket mouse population in the dunes to become lighter and lighter. These mice are less likely to be eaten and more likely to survive and pass on their light-colored genes. Over time, they evolved to be almost white in color! How? Well, here in the glaring white sand dunes, lighter colored mice are harder to see. The Apache pocket mouse ( Perognathus flavescens Apachii), a subspecies of the aforementioned plains pocket mouse, adapted to snow-white sand found in the park. So what can they do? Some stay in shrubbier areas of the park outside the dunefield, where there’s more cover and their typically light brown coats better match the soil. Coyotes, owls, snakes, kit foxes, bobcats, badgers, and even leopard lizards and pallid bats have been known to munch on mice.Ĭlearly, predation is a major threat to our resident rodents.
They’re a food source for many predators that live in or around the dunes. Their efficient kidneys minimize water loss and allow pocket mice to go weeks without drinking water, which is certainly a useful adaptation in the desert!Īs one of the few animals that can thrive in this arid desert environment, pocket mice are also an important link in the White Sands food chain. To cope with the lack of water, many species of pocket mice can get most of the water they need from the seeds they eat. These seeds make up the bulk of their diet and are quickly stored away, first in the mice’s cheek pockets and later in their burrows. At night, pocket mice emerge to forage for seeds. Solitary and nocturnal, these desert dwellers spend the day in their underground burrows, which stay much cooler than the surface temperatures. They manage by carefully conserving water and avoiding the heat. These pocket mice may not look like much, but they’re one of the few animals who can live in the gypsum sand dunefield. Meanwhile, silky and plains pocket mice (genus Perognathus) have soft, smooth fur. Rock and Chihuahuan pocket mice (the two with the genus Chaetodipus) have coarser fur with some long, bristly hairs that resemble weak spines. The main difference between the four species is the texture of their fur. In other words, they look like typical mice. They are small and unimposing with small, round ears, large eyes, and long tails. At White Sands, we’ve found four of these species: the rock pocket mouse ( Chaetodipus intermedius), the Chihuahuan pocket mouse ( Chaetodipus eremicus), the silky pocket mouse ( Perognathus flavus), and the plains pocket mouse ( Perognathus flavescens). These pockets are the uniting characteristic of over two dozen species of pocket mice that live throughout parts of Canada, Mexico, and the United States. Their pocket-possessing relatives include kangaroo rats and pocket gophers.
And pocket mice aren’t the only rodents to have them. That’s right –pocket mice have actual pockets! These fur-lined storage pouches are located on the outside of their cheeks. Pocket mice are members of the subfamily Perognathinae and are known and named for their pockets. Here at White Sands National Park one such rodent is the pocket mouse. Although small rodents may not be the most obvious animals to live in the desert, these tiny foragers are key parts of desert ecosystems. When you think of desert life, what kind of animals do you think of? Do you think of mice? What about rats? If not, maybe you should.
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