AY Honors/Mammals - Advanced/Answer Key
1. Have the Mammals Honor
2. What mammals in your locality are protected by law? Why?
Most mammals are protected by law in the form of hunting seasons and licenses. It is illegal to kill most medium-to-large mammals in most parts of the United States without a license, and these licenses are only good during certain seasons. Mammals which are considered pests or vermin, such as rats, mice, and groundhogs, are not protected in this way. They can be exterminated at any time. But deer, squirrels, opossums, beaver, muskrat, weasels, mink, fishercats, bobcats, mountain lions, and wolves either have a designated season, during which a licensed hunter may kill them, or they enjoy a total ban on hunting.
The purpose of these laws is to prevent population crashes. Generally, hunting seasons are in the autumn, and this is to allow the mammals to reproduce in the spring and summer, but be culled out in before winter sets in. In many cases, hunting is the only predation a mammal knows, and without a hunting season, the population would explode. Large populations of deer, for instance, cannot survive the winter, as the available food resources are limited.
In other cases, mammals are protected because they have been listed as endangered. This means that in our unenlightened past, man hunted them to the brink of extinction, or has eliminated so much of the animal's habitat, that it cannot survive without legal protection.
3. How do the processes of birth and care for the young differ in monotremes and marsupials from all other orders of mammals?
Monotremes
Monotremes include the platypus, echidna, and several other species. Monotremes lay eggs. However, the egg is retained for some time within the mother, who actively provides the egg with nutrients. Monotremes also lactate, but have no defined nipples, excreting the milk from their mammary glands via openings in their skin.
Marsupials
Marsupials include kangaroos, opossums, and several other species. The pregnant female develops a kind of yolk sac in her womb which delivers nutrients to the embryo. The embryo is born at a very early stage of development (at about 4-5 weeks), upon which it crawls up its mother's belly and attaches itself to a nipple (which is located inside the pouch). It remains attached to the nipple for a number of weeks. The offspring later passes through a stage where it temporarily leaves the pouch, returning for warmth and nourishment.
4. Name five different ways in which mammals protect themselves and their young, and cite an example of each.
5. What mammals are agents for the transmission of tularemia, bubonic plague, trichinosis, and rabies?
- Tularemia
- Rabbits are a major agent for the transmission of Tularemia, which is also known as rabbit fever.
- Bubonic plague
- Rodents, primarily rats are responsible for the spread of bubonic plague.
- Trichinosis
- Trichinosis, also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating raw or undercooked pork and wild game products infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm.
- Rabies
- About 50% of the rabies cases in the United States are found in raccoons, though dogs, cats, skunks, and bats are also common sources of the disease. All mammals are susceptible to rabies.
