# Time Resources in Animals (UMAP)

### Author: Kevin Mitchell and Steven Kolmes

This unit presents an alternative to the classical optimal foraging models in behavioral ecology. The model presented in this reading is concerned with a time-budgeting process dependent only upon whether an animal is hungry or satiated at a given moment. The analysis of the model is carried out using simple Markov chains.** Table of Contents:TIME RESOURCES** The Daily Pie

Key Concepts

**THE THERMOSTAT MODEL OF FEEDING**

The Activity and Appetite Functions

Changing Activities

**MODEL I: AN OVERSIMPLIFIED EXAMPLE**

Putting the Model Together: Catepillars

Keeping Track of Changing States

Western Tent Catepillars

Generating Data by Computer Simulation

The Relationship Between d and Resting Time

The Relationship Between b, d, and Resting Time

Eastern Tent Catepillars

**LAZINESS**

MODEL II: VARYING PREY VALUES

The Heron as Forager

MODEL II: VARYING PREY VALUES

The Assumptions about Herons

Two Special Cases

The Relationship Between c, d, and Rest Time (b = 0)

Combining the Results

**A DIFFERENT ANALYSIS: RATES OF CHANGE**

MODEL III: ENERGY LOSS DURING FORAGING

The Cat as Forager

MODEL III: ENERGY LOSS DURING FORAGING

The Mathematical Assumptions

A Single Simplification

A Comment on Desperation

**MODEL IV: THE POSSIBILITY OF STARVATION**

The Changes of State for the Stressed Cat

New Questions: Surviving the Winter

Improving the Rate of Successful Foraging

The Effect of Lowered Energy Loss at Rest

Moderating Winter

Tentative Conclusions

**CONCLUSION**

ANSWERS TO SELECTED EXERCISES

REFERENCES

ACKNOWLEDGMENT

ABOUT THE AUTHORS

APPENDIX: COMPUTER PROBLEMS

ANSWERS TO SELECTED EXERCISES

REFERENCES

ACKNOWLEDGMENT

ABOUT THE AUTHORS

APPENDIX: COMPUTER PROBLEMS

#### Mathematics Topics:

#### Application Areas:

#### Prerequisites:

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