January 10, 2001

Mammals/Trade Rats

Learning Links: Trade Rats -- Facilitator Page

 

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Trade Rats (packrats) belong to the rodent genus Neotoma. They are common in western North America and one species extends into the eastern USA. They are rat sized and only weigh around half a pound, so moving an item as large or heavy as a coffee cup is difficult, if not impossible. Middens, which are large piles of materials protecting the nest, commonly are made of such things as sticks and cactus pads, but almost anything draggable will be used (bones, cow "pies", tin cans, cartridges, gloves, wallets, etc.).

Concept: Play "Fill the Midden" to teach learners how trade rats collect items to use in their middens. This game can also be modified to resemble "Old Maid", where each player could end up with the "Empty Midden" card. Students get an idea of what sorts of things trade rats might collect. They could also use their knowledge to create their own playing cards.

Goals (Measurable): Learner will be able to identify five things a trade rat might collect for its midden. Learners will also be able to name at least one natural and one man-made hazard that could damage or destroy a midden.

Objectives (Not measurable): Learners will enjoy the process of playing a game with others. They will see how luck plays a role in what trade rats keep in their middens.

Materials/Supplies needed

• Two copies of each "Midden Cards" page is available in Adobe Acrobat format (requires Adobe Reader, available as a free download). Cards should be printed out on card stock and cut apart. Remove BOTH "Wild" cards and BOTH "Empty Midden" cards from the deck. Depending on which version of the game you play, you will add one of these cards and possibly remove another card from the deck.

Activity

(Standard form - up to 4 players)

• Randomly remove one of the object cards from the deck, but keep the identity of this card a secret. Add one "WILD" card to the deck, in place of the card removed.
• Shuffle cards. Deal eight cards to each player. Place the remaining cards face down in the center of the players. Players now look at their cards. If they have any two cards that match (two seed cards, for instance), students can put these down, face up, as a pair they have in their "midden". The goal of this game is to get the most things for your midden. Players should NOT put the wild card down at this time - it will be crucial at the end of the game.
• The first player chooses another player and asks for a specific card (you CANNOT ask for the wild card - only for something you already have in your hand). For instance, the player might say "Debbie, do you have a "hat" card?" If Debbie has that card, she must give it to the asker, but since we are trade rats, Debbie will get to randomly choose from the asker's hand, too. This happens AFTER the asker has put down the pair of hats s/he now has. If Debbie gets a match, she can also put down her pair.
• If Debbie does NOT have the card requested, she replies "Go Search", and the asker must take the top card from the deck. S/he does not have to replace it with another card, this time, but if s/he has a match, it can be put down as a pair. Play now continues with the player to the left becoming the new "asker".
• If, at any time, a player puts down his/her last pair, that player must draw one card from the deck. In this way, play will continue until all the cards have been used.
• As the game is coming to an end, the wild card and the card whose mate has been removed will eventually be the only two cards left in play. Whoever is able to get both these cards at the same time can put them down into his/her midden. (Possible modification: you could let players pair the wild card earlier, IF that player is convinced s/he knows which card is missing a mate. If, however, that player puts the wild card down with a card that has the mate, the person holding the mate should show everyone that the other player chose the wrong card. The player will have to give up ALL his cards, both those with mates and those without, and shuffle them into the deck. S/he could be given the "empty midden" card to show what the mistake cost!)
• Once all the cards are down in the middens of all the players, each player counts the number of PAIRS in his/her midden. The player with the most objects wins.

("Empty Midden" form - up to 4 players)

• Insert ONE "Empty Midden" card into the deck. It will be the only card without a mate, and it is card players will want to get rid of, if possible.
• Shuffle and deal eight cards to each player, and play as specified above, with each player requesting (and exchanging or drawing) cards until all the cards have been played. The player left holding the "Empty Midden" card loses. If you wish, you could say that this player had a natural disaster (a mud slide, for instance) or human vandalism destroy his/her midden.

Conclusion:. Discuss with learners what a midden is and why trade rats have them. What sorts of things could destroy a midden (both natural and man-made)? Are the trade rats in any danger because of things they may pick up? (Do you think a trade rat might pick up a bullet, for instance, or some other human item that can be dangerous to play with?)

Resources

• Bailey, V. 1931. Mammals of New Mexico. North American Fauna no. 53:1-412.
• Betancourt, J. L., T. R. Van Devender, and P. S. Martin (eds.). 1990. Packrat Middens, The Last 40,000 Years of Biotic Change. University of Arizona Press, Tucson, 467 pp.

(Note that these are only some of the possible standards one could cover with this activity. Depending on how each person uses the activity, it may be used to support different standards.)

Texas Essential Knowledge and Skills (TEKS) - Science
• Students use models, recognizing their strengths and weaknesses
• Students identify components of the natural world
• Students compare various characteristics and adaptations, realizing that these help species survive in the natural world.
• Students understand the impact of human activity on the natural world. They are aware that the environment changes over time as a result of both natural and human factors.
• Students understand that a change in the environment can affect the survival of individuals and species.
• Students can predict how natural or human events may contribute to the extinction of some species. They understand the need for conservation.
• Students consider the impact of different catastrophic events on the earth.
National Science Education Standards - Content Standards
• Unifying Concepts and Processes
• Evidence, models, and explanation
• Science as Inquiry
• Characteristics of organisms
• Organisms and their environment
• Diversity and adaptation of organisms
• Behavior of organisms


Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.