In this episode, Matt and Kevin are joined by [Nicole Ackermans](https://nicoleackermans.com)
to discuss her recent review paper tracing human thoughts about headbutting
from 10,000 BCE to the present day.
How are animals like bighorn sheep and woodpeckers protected
from brain injury?
Actually, wait... **are** they protected from brain injury?
Matt and Kevin take a humbling look back a classic 1989 immunology paper
from the lab of David Baltimore (RIP)
in which the gene encoding RAG-1,
one of two genes that is responsible for
the VDJ recombination -
a mechanism for the generation of diversity
in the adaptive immune system.
