Illinois Natural History Survey - University of Illinois

snakes.TIFAnimals Make Scents—The Pheromone Game  by Carolyn Nixon and Michael Jeffords

Scents are important to animals in more ways than just defense. Different scents may be used to mark territory or attract a mate. Scents produced by an animal to give a chemical signal to other animals are called pheromones. Pheromones help many animals to find mates. To demonstrate how pheromones work, let’s play the Pheromone Game.




• 18 baby food jars with lids

• aluminum foil or black paint

• a punch or a sturdy nail and a hammer to punch holes

• 3 each of 6 different common food items with distinct odors: (examples include garlic, slices of lemon or orange, chocolate, peanut butter, cotton ball soaked with coffee or vanilla extract)




1.  Cover each jar with aluminum foil or paint the jars black. Punch five or six holes into each jar lid. Number the jars consecutively, 1 through 18. Place a sample of one of the six items with distinct odors into each of the jars; replace the lids and number the jars.  There should be three jars of each food item. Record which items are in which jars on a sheet of paper. Randomly place the jars about the room.


2.  Write the names of each of the six items on separate slips of paper, one for each player. racoons.TIF


3.  This is a silent exercise and no talking or other communication will be allowed. Ask each player to list the numbers from 1 through 18 on a sheet of paper and to carry this list and a pencil throughout the exercise. Show each player one of the six slips of paper; this is the special odor for which they are to search; no other odor is of interest to them. Players then sniff the contents of each jar and place an X opposite the numbers on their lists that correspond to the numbers on the jars that they think contain the special item for which they are searching.


4.  After the sniffing has concluded, reveal the contents of each numbered jar so that players can check the accuracy of their noses. An accurate nose should have detected the same scent in three different jars. 


If players successfully identified the correct scents, they would have been able to reproduce.  If they made mistakes, they would have failed in those attempts.  


Teachers Guide to The Naturalists Apprentice

Notes for Teachers and Parents


Explain that if animals make errors in choosing a mate, they will not be able to reproduce.  This would be a dead end. Injury or death may result if the wrong mate is chosen.


Closely related species occasionally produce hybrids (a cross of two different species). Include some scents that are similar (orange and tangerine slices, for example) and determine what percent of the population would make mistakes when picking a mate.  Explain that most hybrids either die or are sterile (unable to reproduce themselves), so this would likely be a dead end. A common example of a hybrid is a mule, which is a cross between a horse and a donkey.


Classes can be divided into six groups, each representing one species, but each student must sniff and record his or her results individually.


“The Naturalist’s Apprentice” presents educational activities for middle school students. Teachers are invited to
photocopy this page for classroom use.

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