http://www.ck12.org Chapter 11. Understanding Biodiversity: Animals: Mammals
Habitat
The range that this rabbit lives in is the western United States, as far north as eastern Montana and south into Mexico.
S. auduboniican be found in several communities: grasslands, desert areas and woodlands. The plant communities
that can be found where this organism lives are sagebrush and shrublands. You can find this rabbit in elevations from
below sea level to 6,000 feet.
Biology
Cell Biology
Audubon’s cottontail rabbit has eukaryotic cells. This means they have a nucleus and lots of organelles. Organelles
are like microscopic organs. These organelles include the Golgi bodies, cellular membrane, and the ribosomes. The
DNA (deoxyribonucleic acid) is not an organelle but a chemical and consists of genes with “codes” to make proteins.
Ribosomes are where proteins are made. The Golgi bodies help transport the proteins in the cell or to the cellular
membrane.
Many animals have red blood cells, but in mammals they have no nuclei. Red blood cells carry oxygen from the
lungs all around the body using hemoglobin.
Mitosis is a form of a kind of cell division, where the nucleus of a cell divides, and two new cells with the same
DNA as the original cell are formed. Another form of cell division is meiosis, in which gametes are made with one
half the chromosomes of the original cell.
Evolution
The first species ofS. auduboniiwere found in mountains of Texas, Mexico and other southern mountains. Later a
subspecies was found in the Guadalupe Mountains of Texas and New Mexico. The first of the family’s fossils were
found in North America.
The earliest traces of mammals came from cynodonts. Placental mammals are thought to have evolved just after the
extinction of dinosaurs about 65 million years ago.
Ecology
SinceS. auduboniieats grass, fruit, and nuts, they are herbivores. Audubon’s cottontail eats things that are mostly
low in protein, high in fiber. These rabbits are a good source of food for coyotes, foxes, hawks, badgers, and the
bobcat. The cottontail is also a disperser of seeds. This means that the cottontail helps plants grow by carrying the
seeds all around.
On averageS. auduboniihas three young per litter, and up to five litters a year. Audubon’s cottontail rabbit gives
birth during mid winter and late summer. Their age of maturity is three months. The lifespan in captivity is around
7.8 years, but the lifespan in the wild is about 1-3 years.
Anatomy and Physiology
S. audubonii, like other mammals, has mammary glands in the mother, and babies drink milk. When a cottontail is
born it is blind and naked. Audubon’s cottontail can run as fast as 15-18 mph. They have large back legs with large