Review Food Web-12

The Common Raven is often a scavenger, but its beak is not strong enough to tear through the thick hide of a winter-killed deer.

It will sit near the carcass and call loudly, attracting other ravens. As the mob gathers, they start making distress calls. That usually attracts a large predator, such as a wolf or coyote. They wait until the predator tears into the carcass.

At that point, 3 or 4 of them will start harassing the predator, keeping its attention, while the other ravens steal parts of the carcass. They then share what they get with the ravens that kept the predator busy.

This is an example of what kind of relationship?

  1. mutualism

    Yes! In mutualism, both organisms benefit. The ravens help the predator find the carcass, and the predator tears it open so that the ravens can eat some too. Both get a benefit from the relationship.
  2. commensalism

    No. In commensalism, one organism benefits, and the other is not affected. In this case, the ravens and the predator both benefit.
  3. parasitism

    No. For parasitism, one organism benefits, and the other is harmed. Neither the raven nor the predator is harmed by this relationship.
  4. predation

    No. In predation, one organism eats another. Neither the raven nor the predator gets eaten in this relationship.

Click to see which state standards this question tests, and which of my videos, experiments, and other resources support that topic.


SC.7.L.17.2 Compare and contrast the relationships among organisms such as mutualism, predation, parasitism, competition, and commensalism.
Secondary Consumers video, ClosedCaptions
Review Food Web-11 practice
Review Food Web-12 practice


UT.8.II.2.a Categorize the relationships between organisms (i.e., producer/consumer/decomposer, predator/prey, mutualism/parasitism) and provide examples of each.
Secondary Consumers video, ClosedCaptions
Producers video
Primary Consumers video, ClosedCaptions
What is a Food Web? text page
Review Food Web-9 practice
Review Food Web-10 practice
Review Food Web-11 practice
Review Food Web-12 practice
Review Food Web-2 practice
Review Food Web-1 practice
Review Food Web-3 practice
Review Food Web-4 practice
Review Food Web-5 practice
Review Food Web-6 practice
Review Food Web-7 practice
Review Food Web-8 practice


MS-LS2-2 Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.