Mateo Rull learned about Quetzalcoatl and Xolotl, the Aztec gods of life and death, while growing up in Monterrey, Mexico. 
In the Aztec creation story, Quetzalcoatl and Xolotl travel to the underworld to fetch the bones of creatures from past worlds so that they can fashion them into new life for the present world, the world of the moving sun. 
All of the gods agree to sacrifice themselves so that this new sun will move across the sky – all, that is, except Xolotl. To escape death at the hands of the wind god, Xolotl transforms himself into a salamander and hides in Lake Xochimilco beneath the Aztec capital of Tenochtitlán, now Mexico City. 
When Rull arrived at UMass Lowell as a first-year psychology student, he found a work-study job in the Biology Department. There, he met Asst. Prof. Nicolai Konow – and discovered that he was working with axolotls (pronounced “ax-uh-lot-uhls”), the “Mexican salamander” that the Aztecs worshipped as avatars of the god Xolotl. Rull asked to work in Konow’s lab.
“If that’s not a sign, I don’t know what is,” Rull says, laughing. “I fell in love with the axolotls, and that’s what drew me into the research at first. They’re so beautiful and so fascinating, and the Aztecs really revered them.”
Rull had originally planned to do research in mental illness as a neuroscientist, after moving to western Massachusetts at age 16 and taking an AP psychology class in high school. But over time, he became more interested in Konow’s work in evolutionary and functional biology.
Axolotls are widely studied because they can regenerate any part of their body that’s been damaged. Konow studies them because they also represent an evolutionary link between fish and some of the earliest land-based vertebrates. Although axolotls spend their lives underwater in nature, they have lungs and feet. In rare cases in the wild or under carefully controlled laboratory conditions, they can undergo metamorphosis and live on land like their close cousin, the tiger salamander.
Rull added a second major in biology and joined the Honors College, continuing his research in Konow’s lab with financial support from an Honors College Student Fellowship and the Urban Massachusetts Louis Stokes Alliance for Minority Participation, a National Science Foundation program.
In the spring of his junior year, Rull published a paper as lead author, with Konow and Jacob Solomon ’17, on the mechanisms of food processing in aquatic axolotls. It appeared in the biology journal Proceedings of the Royal Society B. 
The following summer, Rull worked in an animal movement research lab at the University of Chicago through The Leadership Alliance’s Summer Research-Early Identification Program. Because of the COVID-19 pandemic, Rull worked virtually, analyzing X-ray videos showing the movements of the rhesus monkey’s tongue bone as it vocalizes and eats.
Now Rull is planning to apply to Ph.D. programs and pursue a career in animal movement research. He’s endlessly fascinated by animals and all of their evolutionary adaptations.
“With cheetahs or mountain-climbing goats or fish that can swim at incredible speeds, you get to look at how powerful Mother Nature is in creating specialists that can deal with their environment,” he says.