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Project Summary

Difficulty	3
Time required	Average (about one week)
Prerequisites	None
Material Availability	Readily available
Cost	Low ($20 - $50)
Safety	No issues

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Abstract

Objective

In this experiment you will compare the food intake of your family pets to find out which pet eats more for its body weight.

Introduction

Are you in charge of feeding your family pet? If so, then you know that your pet needs food! The need for food is something called a nutritional requirement. Food provides an animal with all of the nutrients it requires to survive: vitamins, minerals, protein, amino acids, sugars, and carbohydrates.

Do these sound familiar? That is because you need them too! After all, humans are animals, and we have nutritional requirements just like other animals do. It is interesting that different kinds, or species, of animals have different nutritional requirements. Different kinds of animals eat different kinds of foods, which provide different nutrients as part of their diet.

The amount of food that an animal eats can be due to many different factors, like: age, weight (body mass), diet (herbivore, carnivore, omnivore, insectivore), health (illness, obesity, pregnancy), activity level, or metabolism. In this experiment you will investigate which pets eat more than other pets by comparing the food intake of different species of pets. Food intake is how much food your pet eats, and can be measured by weighing the dry weight of your pet's food in grams and adjusting for body weight (body mass). Which pets in your experiment will eat the most?

	-VS-
Which species of pet will eat the most food for its size? (images courtesy of Tenderfoottraining.com and Chris Bennett, SFSU)

Terms, Concepts and Questions to Start Background Research

To do this type of experiment you should know what the following terms mean. Have an adult help you search the Internet, or take you to your local library to find out more!

• Nutrition
• Food intake
• Body mass
• Metabolism

• How much food does my pet consume?
• Considering the size of each pet, which pet eats more food per unit body mass?
• What types of pets eat the most food for their body weight?

Bibliography

• Petco has a great database of Animal Care Sheets that include information about diet and feeding requirements for many different pets, ranging from Dwarf Angelfish to Hairless Hamsters:
  PETCO, 2007. "Animal Care Sheets," PETCO Animal Supplies, Inc. [accessed June 6, 2007] http://www.petco.com/CareSheets/petco_CareSheets_Nav_154.aspx
• The Saint Louis Zoo has this interesting article about zoo animal nutrition:
  St. Louis Zoo, n.d. "Animal Food and Nutrition Center," St. Louis, MO: Saint Louis Zoo, Animal Food and Nutrition Center, Department of Nutrition. [accessed June 6, 2007] http://www.stlzoo.org/animals/animalfoodnutritioncenter/
• Want to know what a career in animal nutrition is like? Read this interview with Mark Edwards, an animal nutritionist for the San Diego Zoo in California:
  Sullivan, M., 2004. "An Interview with Animal Nutritionist Mark Edwards," National Science Teachers Association (NSTA). [accessed June 6, 2007] http://www3.nsta.org/main/news/stories/science_teacher.php?news_story_ID=49461

Materials and Equipment

• Two (or more) very different types of pets:
  • Dog
  • Turtle
  • Cat
  • Lizard
  • Frog
  • Rat
  • Rabbit
• Pet food for each type of pet tested
• Metric scale to weigh pets and pet food

Experimental Procedure

1. Prepare a daily log in a laboratory notebook to record your data. The data you will record each day will be the weight of food you feed your pets. Here is an example to help you design the data table in your log:

   Type of Pet	Weight of Pet (g)	Daily Weight of Food (g/day)							Average Daily Weight of Food (g/day)
   		Mon	Tues	Wed	Th	Fri	Sat	Sun
   Grover the Dog
   Rocky the Turtle
   Sneezy the Rat

2. Weigh each pet and record the weight in kilograms (kg) in your log book. For smaller pets, you can weigh the pet on a small metric kitchen scale. For larger pets, you can hold the pet and take your weight together, then subtract the weight of yourself to get the weight of your pet. You may also be able to get your pet's weight from your veterinarian, which is important if your pet is a horse or the family cow and too big for you to pick up!
3. Each day before you feed your pet, weigh the food in grams using a metric kitchen scale. Record the weight of the food in grams in your daily log. You will need to do this for one week.
4. At the end of the week, calculate the average daily mass of the food your pet ate during the week. Do this calculation by adding together the weights of a weeks worth of food, and then dividing your answer by seven.
5. Now you need to adjust (normalize) the amount of food each pet eats per day to take into account the body weight of that pet. This can best be expressed as the ratio of food weight in grams per kilogram of the pet's body weight (g/Kg of body weight). To calculate this ratio, first make yourself another data table:

   Type of Pet	Average Daily Food Intake (g/day)	Weight of Pet (kg)	Food Intake (g/kg/day)
   Grover the Dog
   Rocky the Turtle
   Sneezy the Rat

6. Divide the data in column two by the data in column three, and the answer will express the ratio of food weight (g) to pet weight (kg) and should be written into column four.
7. Lastly, make a bar graph (histogram) of your data so that you can analyze it. Make a scale on the left side of the graph for the ratio you calculated, and draw a corresponding bar for each pet in your analysis. Are they the same or different? Do you notice any patterns?

Variations

• Are there other ways to normalize (adjust) your data besides using body mass? What about measuring the heart rate of the pet? Then you can investigate if the amount of food a pet consumes is related to their metabolism. What about the age of the pet? Any other variables you can think of to test?
• You can do a similar experiment to investigate food choice amongst pets. Make a separate dish of each food you supply for your pet. Weigh each dish before and after you allow your pet to eat, and record a week's worth of data in a daily log. At the end of the week, the food that has the largest difference in weight before and after feeding is the food your pet prefers.
• What about your family? Who eats the most? Is it the person who weighs the most or the least? To find out, weigh your family members and keep track of what they eat for a week. But it is important to make sure they are all willing volunteers for this experiment first!

• For more science project ideas in this area of science, see Zoology Project Ideas.

Credits

This project was adapted from a student project submitted to the Marin County Science Fair in California.

Sara Agee, Ph.D., Science Buddies

Last edit date: 2007-09-17 23:00:00

Career Focus

If you like this project, you might enjoy exploring careers in Zoology.

	Zoologist and Wildlife Biologist Ever wondered what wild animals do all day, where a certain species lives, or how to make sure a species doesn't go extinct? Zoologists and wildlife biologists tackle all these questions. They study the behaviors and habitats of wild animals, while also working to maintain healthy populations, both in the wild and in captivity.			Animal Breeder Why is it that certain breeds of cattle produce more flesh or milk? Why is one horse faster than another? The answer is that these breeds were engineered to have these special characteristics. Animal breeders need to understand genetics in order to produce animals that are bigger, faster, or more beautiful. If you are interested in working with animals and are fascinated by the science of genetics, then you should investigate this career.
	Biologist Life is all around you in beauty, abundance, and complexity. Biologists are the scientists who study life in all its forms and try to understand fundamental life processes, and how life relates to its environment. They answer basic questions, like how do fireflies create light? Why do grunion fish lay their eggs based on the moon and tides? What genes control deafness? Why don't cancer cells die? How do plants respond to ultraviolet light? Beyond basic research, biologists might also apply their research and create new biotechnology. There are endless discoveries waiting to be found in the field of biology!

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