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2-6 Armadillos

Adding Armadillos

(Adapted from ZPG’s Elementary Population Activities Kit)

In the wild, the nine-banded armadillo of North and South America lives about three years after reaching maturity, and mates and produces four litters of offspring each year. We will study one such armadillo family that begins with Mamadillo and Papadillo, and figure out what it looks like in three generations (when Mamadillo is a grandmother).

Mamadillo and Papadillo mate and have one litter a year for three years. Each litter is always four little female armadillos. We will assume that each female successfully finds a mate from some other litter.

Question 2.14.
What is the total number of baby armadillos borne by Mamadillo, her offspring, and their offspring, in the three years?

***Extra challenge!***

At this rate, how long would it take for there to be more than 2000 armadillos? Why aren’t there very many armadillos today?

Make a table like the one shown on the next page. Graph the population of armadillos from your results. Your independent variable is the time, and your dependent variable is the number of armadillos.

Remember that earlier in the book you read about what would happen if all the elephants born survived. Would the same situation occur eventually with armadillos? What limiting factors prevent us from being up to our arm pits in armadillos?


Table of Armadillo Population--Offspring of Mamadillo and Papadillo

Year A
Offspring from one year ago
[D, prev. line]
Offispring from two years ago
[D, 2 lines up]

Offspring from three years ago
{D, 3 lines up]

New offspring
[4F, 1 line up]

TOTAL females
[1 + D + E]

0 Originally there are two armadillos, Mamadillo and Papadillo ---- 0 1
1         0  
2         0  
3         0