Self-study
In the spring and fall, eastern pipistrelle bats roost deep inside caves. ████ ████ ██ █████ ██ ██████ ███████ ███ ████ █████ ███ ████ ██ █████ █████ █████ ██████ ███████ ███ ████ ████ ████████ ██ ████ ██████ ████ ██ ████ █████ ███████████ █████ ████ ████ ████ ████ █████ ███ █████ ██ ████ ██████ ████ ██ ████ ███████ ████ ██████ ███ ███████████ ██████ ███ █████ █████ ███ ████ █████ ███████ █████████ ███ ████ ████ ███ █████ ██ ███ █████
"Surprising" Phenomenon
Bats leave their caves more often on warm, food-abundant nights than on cool nights, despite seemingly not having any way of knowing it’s a warm night outside the cave.
Objective
The right answer will be a hypothesis explaining how bats know it’s warm out despite their caves not changing temperature. The explanation must provide some way for bats to know the temperature without feeling the temperature directly.
4.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████████ █████████
a
The researchers studied ████ ██████ █████ █████ ██████ ██ █████ ████ ███████ ██ ████ ██████ ████ ███ ███ ████ █████
We don’t care about how many bugs the bats are catching. We need to know why more bats are leaving their caves on warm nights to begin with.
b
Eastern pipistrelle bats ███ ██████ ███████ ██ ██████████ ████████ ██████ ███ █████ ████ █████████ ███████ ████ ███████ ██ ███████████ ███████ ███ ██████
Even though the temperature in the caves doesn’t change, the barometric pressure does. And barometric pressure is closely linked to temperature changes outside the cave. Thus, bats have a way of knowing if it’s a warm night.
c
Eastern pipistrelle bats ███ █████████ ██ ████ ███████ ██ █████████ ████████ ███████ ███ ████████ █████ ██ ████ ████ ██████ ███ ████ █████████
This still doesn't explain how the bats can tell if it's warm when the cave stays the same temperature. We need something to explain how bats know if a night is warm or not.
d
Because of the ████ ██████ ██ ██████ ███████████ ███████ ███████████ ████ ████ ██ ███████ ████ ███████ ███ ███ ██ ███ ██████ ███ ████ ████ ██ ███ ███████
All we're concerned with is the bats' behavior during the spring and fall seasons. This doesn’t explain how bats know if it’s a warm or cool night.
e
During the periods ██ █████ ███ ███████████ ███████ ███ █████ ██ ████ ████████ ████ ████ ██ ███ ████ ████ ███ █████ ██ ██████ ██ █████
It doesn’t matter how many total bats are leaving their caves. We need to know why more bats are leaving their caves on warmer nights, despite bats seemingly having no way of knowing the weather while in their caves.