http://www.ck12.org Chapter 11. Understanding Biodiversity: Animals: Mammals
Habitat
D. virginianalives in North and Central America. It lives in many areas including rainforests, urban settings, and
wetlands.
Biology
Cell Biology
D. virginiana, like all mammals and other animals, has eukaryotic cells. Eukaryotic cells have nuclei and other or-
ganelles. Organelles are like micro-sized organs. They include the endoplasmic reticulum, Golgi bodies, ribosomes
and mitochondria. The Golgi bodies are carry protein within and out of the cells. Ribosomes produce protein in
the cell, and mitochondria is where the cell burns sugar for energy. All animals have eukaryotic cells in their body,
so that is not unique to the opossum.
Evolution
Marsupial evolution has dated back to 130 million years ago during the Cretaceous period. The Cretaceous period
was the the time period when the dinosaurs died out. The earliest form of the marsupial wasSinodelphys, which is
an extinct animal now. Early marsupials were very small, and ate small insects.
Ecology
Possums don’t interact with other species as much because the Virginia opossum is prey to many animals. Opossums
are prey to coyotes, bears, foxes, mountain lions, and other large mammals. The opossum’s diet however consists of
insects, frogs, snakes, small mammals, roadkill, and trash. Opossums mate 2-3 times a year, so they could possibly
give birth to 75 young a year. The mother can have 25 babies at a time. When the babies are born, they attach to the
mother’s feeding stations. However, the mother only has 13 feeding stations, so 12 out of 25 will not survive. Even
for the fortunate babies that have latched on to the mother, they can grow ill very quickly.
Anatomy and Physiology
Virginia Opossums have 50 teeth, more than any mammal. Male opossums have a forked penis, and female opossums
have a forked vagina. Virginia opossums tend to have many young. When Opossums give birth, they can have up to
25 offsprings. The Virginia Opossum, like all other mammals, has mammary glands.
Behavior
Opossums are not normally aggressive, but they will be if threatened or harmed. They will hiss defensively, warning
the predator to stay back. If in terror, they will drop and mimic death.
References
- Encyclopedia of Life, http://eol.org/.