The brass rat

In 1929, a student committee assembled to design a standard MIT class ring. After debating whether to feature the Great Dome or the beaver on the bezel, they realized that many schools have a dome, but only MIT has such a clever and industrious mascot. The beaver won out and the brass rat was born. Every undergraduate class since has formed a “Ringcomm” to design and produce its own version of the iconic ring. Symbols in recent designs include the 2019 ring’s ripple in the river for LIGO’s discovery of gravitational waves and 2021’s depiction of the solar eclipse that occurred days after the class arrived at MIT.

The most recent addition to the brass rat is the "Hacker's Map," a guide to the tunnels underneath campus that now appears on the inside of the ring. MIT.nano was added to the Hacker's Map for the Class of 2021's ring.

Students wear their rings with the Boston skyline facing them; at graduation they flip the ring so the Cambridge skyline faces them, to represent their off-campus perspective as alumni.

The 2012 brass rat, which includes a model of the Apollo lunar lander on the Great Dome, traveled aboard the space shuttle Endeavor to the International Space Station in  February 2010. Astronaut T.J. Creamer, SM '92, received it.

In 2016, Stephen Meyer '64 was reunited with his brass rat 50 years after losing it while washing a car on a visit to Alabama.

The brass rat has appeared on the silver screen multiple times. Wearers include Tony Stark in the Iron Man movies and Erin Gilbert, the ghost-busting paranormal investigator and Columbia physicist in 2016's Ghostbusters.