Predators and Prey

How do fish catch dinner?

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Challenge: Hunting for Food and Escaping Predation.

• Review the worksheet section on predation and swimming from Visualizing Life Histories of Tuna, Stingray, Jellyfish and retrieve your fish from Constructing a ‘Fish’. 
• Divide the class in half as Predator and Prey Teams
  • Prey: The prey team will pull their fish by the string attempting to escape from predation as they slowly walk around the room. Before the activity begins, teams will secretly discuss strategies for evading predators (e.g., rapid swimming, hiding, ducking, squeezing into tight spaces, etc..). Multiple prey teams may work together on their strategies if desired.
  • Predators: The predator teams will also discuss their strateg(ies) to chase and then ‘tag’ the prey fish by touching it with their balloon. Predator teams may also collaborate on their predation strategies if desired.
• When ready, the prey teams are given a 5 second head start to begin moving around the room pulling their fish by the strings. The predator teams will then pull their fish towards the prey fish. Students should walk at a steady pace rather than run.
  • If the classroom is too crowded, some teams can potentially move out into the hall or outside to simulate other oceanic environments (for example, a crowded classroom could be compared to a coral reef with lots of hides, while an empty hall would resemble open ocean).
  • Think about the demands of each environment. Where is agility and maneuverability the most advantageous? What about speed? What are the benefits and drawbacks of each? (Hint: Would it be easier or harder for a fish swimming very fast to make sharp turns? How does body shape and size play into it? Would it be useful to predators in open ocean to make tight turns in the first place?)
• Successful predation occurs when a predator fish balloon touches a prey fish balloon. Each round lasts a max of two minutes, so that multiple rounds may be played.
  • Prey and predator teams may switch roles if enough time is left over. 
• After each round, teams discuss what strategy worked well. Fins, tails, or weight may be adjusted as needed to improve efficiency. 
• What forces were apparent? What additional body parts or forces would be helpful to add to your fish (i.e., propulsion mechanism?)

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Extension Activity using a Fish Example

Manta Ray example

In the predation simulation, we modelled hunting behavior off of solitary mechanics used by the animals introduced. But sometimes, independent hunters may group together to improve their yield. Manta rays, for example, are intelligent and capable of complex social interactions including group hunting and play behaviors. Watch this video to see group hunting in action.

As shown in the video, the mantas ‘stack’ on top of one another to enable the leader to consume more plankton, and take turns so each participant gets a fair share. If this mechanism works well for the rays, why not be group animals all the time? What are the benefits and drawbacks of working together or working independently in mantas, as well as the other organisms (tuna and jelly) we have discussed today? (Hint: Think about the environment. How easy is it to find other individuals out in the open ocean? What about competition for resources?)

Climate Change

Perhaps….as the water warms due to climate change in the North Atlantic, will the warmer water impact how jellyfish move with current or how fish swim? We do know that warm water holds less dissolved oxygen, and that commercially important fisheries are moving northward (e.g., cod).  Will tuna be impacted?  Learn more about tuna from NOAA here.

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Next Steps

Have you built a BLIMP? If so, you can start to put what you have learned into action with practicing Collective Behaviors using your BLIMPs.

If you are not yet ready to build a BLIMP, consider diving into Form and Function or return to the Curriculum to pick your next steps.

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Last updated: November 22, 2022.