Exercise 17.2

1. Human beings who perfume themselves are not much different from other animals.

2. Animals as varied as insects and dogs release pheromones, chemicals that signal other animals.

3. Human beings have a diminished sense of smell and do not consciously detect most of their own species’ pheromones.

4. The human substitute for pheromones may be perfumes, especially musk and other fragrances derived from animal oils.

5. Some sources say that human began using perfume to cover up the smell of burning flesh during sacrifices to the gods.

6. Correct.

7. The earliest historical documents from the Middle East record the use of fragrances, not only in religious ceremonies but on the body.

8. In the nineteenth century chemists began synthesizing perfume oils, which previously could be made only from natural sources.

9. The most popular animal oil for perfume today is musk, although some people dislike its heavy, sweet odor.

10. Synthetic musk oil would help conserve a certain species of deer whose gland is the source of milk.

17.3

Baby red-eared slider turtles are brightly colored, with bold patterns on their yellowish undersells which serve as a warning to predators. The bright colors of skunks and other animals signal they will spray nasty chemicals. In contrast, the turtle’s colors warn large mouth bass that the baby turtle will actively defend itself. When a bass gulps down a turtle, the feisty baby claws and bites, forcing the bass to spit it out to avoid a similar painful experience. The bass will avoid other baby red-eared slider turtles. The turtle loses its bright colors as it grows too big for a bass’s afternoon snack.