Living in groups

Why do bats live in massive groups in Texas?

Bats have to be in all place at one -

• Eat moths that migrate

• High body T and metabolic rate, need very reliable source of food

Where have bats moved out of the cave and into in Texas?

Under bridges

Are juveniles bigger from bridge or cave roosts? Why?

Bridge roosts

• Competition, parasites, disease?

  • There must be cost of living in cave for bats

What do groups of prey attract?

Groups of predators

What is the cost of living in groups?

Predation

What is the selfish herd theory?

individual is less likely to be attacked if they’re clustered together

• animals join group to protect themselves rather than their group

Does being in the group protect the animals from getting eaten?

Yes

What are the reasons to group to avoid predation?

• Selfish herd theory

• Predator satiation

• Reduced vigilance

• Predator confusion

What is predator satiation?

Higher density protects - predators can only eat so much at once

• Prevents predator aggregation - allows satiation mechanism to work .

How does group allow group vigilance and how is this beneficial?

• Bigger groups - more time foraging

  • Don’t have to look around as much

How does predator confusion work?

More individuals - lower success rate for attack