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Saturday, April 23, 2016

Territory and Trophic Levels

Some ecological terms define themselves. Territory is the area in which an animal will defend as theirs to live and feed. Competition between animals of the same species also includes animals of different species that feed alike.

A gentleman that did a Bird's of Prey presentation at Georgia Southern University spoke of how he was going to train a falcon to hunt with his Jack Russell. The training did not last long. The Jack Russell was unharmed from the falcon's instinct to take it down first. Species that compete for food are natural enemies.

Trophic level is the level at which an organism feeds. The first trophic level are the producers or green plants. There are a few organisms that live in the deep ocean that use chemosynthesis to produce food. They do not make nearly the amount of energy for the effort as green plants do.

The second trophic level are the herbivores.

The third trophic level are small organisms that feed on plants, animals, decaying matter or a combination of these items. Some animals are called opportunistic eaters. They eat whatever is available. Examples are bears, squirrels, opossums. There are videos of deer eating small birds. Many herbivores do eat animal matter in small quantities compared to their primary diet.

The fourth trophic level are carnivores or meat eaters. They have varying amounts of vegetative matter needs which are usually satisfied with whatever is in their herbivore's prey's stomach. When weak, sick or elderly, this group feeds more on dead and decaying organisms. This level would contain, hawks, eagles, foxes, panthers, wolves.

A truth of each level is that only ten percent of the food eaten by any organism is used to build new tissue. Ninety percent is used in day to day living of looking for another meal, maintaining body heat or reproducing. Interesting enough, a great deal of food is needed to maintain body heat.

The size of a large cat determines how much meat is needed each day. Non-domestic cats are obligate carnivores and their bodies are unable to break down plant material for the nutrients they need. A cat smaller than 40 kilograms (88 pounds or 6 stone, 4 pounds) needs about 4 percent of their body weight a day. That would be 12 pounds of meat for a approximately 14 kilogram (30 pounds or 2 stone, 2 pounds) cat  or 16 kilograms(35 pounds or 2 stones, 7 pounds) of meat for a 40 kilogram (88 pound) cat. Cats larger than 40 kilograms (88 pounds) require 1 1/2 to three percent of their body weight in meat.

An alligator needs to eat 8 to 10 percent of their body weight per week. Or about 1 to 1 3/7 percent of their body weight a day. Alligators and other reptiles are usually fed once a week. This suits their needs compared to how they would eat in the wild and their low metabolism. The drop in the amount of food needed compared to warm blooded animals should be noted. This is due to not having to maintain body heat. Like warm blooded animals, alligators decrease their food requirements with size and age.


  1. This is most informative. The food chain is a complex entity indeed!
    @yenforblue from
    Spice of Life!

  2. Great post. It's amazing how much energy is used generating heat and finding food.
    Amanda (from

  3. I wonder how much food in terms of weight to food ratio we'd need as a species? Enjoyed the read as always.

    Ninja Minion, A-Z 2016

  4. Wow! I haven't thought about biology or the delicate eco-system for a long time! Thanks for the refresher course. I enjoy your blog. Do you two of them?


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