mikkipedia:

Did you know that because of their migration patterns—from Alaska to Baja and back, every year—Pacific gray whales have alternating colors in their ear wax? After they die, you can extract the big core of ear wax and see how old they are by counting the rings. JUST LIKE TREES.

mikkipedia:

Did you know that because of their migration patterns—from Alaska to Baja and back, every year—Pacific gray whales have alternating colors in their ear wax? After they die, you can extract the big core of ear wax and see how old they are by counting the rings. JUST LIKE TREES.