Mexican researcher spends 25 years studying remarkable fish-eating bats that thrive in desert islands

A chance discovery on a remote desert island in Mexico’s Gulf of California has led to a quarter-century scientific odyssey studying one of nature’s most unusual mammals. José Juan Flores Martínez, now an academic technician at Mexico’s National Autonomous University (UNAM) Institute of Biology, first encountered fish-eating bats (Myotis vivesi) in the early 2000s while volunteering on a rodent control program near La Paz.

What began as routine conservation work turned extraordinary when Flores Martínez heard clicking sounds beneath his feet on Isla Partida Norte. Instead of finding bats in their typical cave habitats, he discovered them emerging from rock crevices in one of Mexico’s most extreme environments. These remarkable creatures survive in desert conditions ranging from sub-freezing temperatures to scorching heat above 122°F (50°C).

The fish-eating bat proved even more fascinating than its harsh habitat suggested. As the largest bat in its genus, reaching up to 6 inches in length, it possesses waterproof fur that enables it to hunt fish from ocean surfaces—an extremely rare feeding behavior among bats. This unique adaptation allows the species to thrive on islands where traditional bat food sources like insects are scarce.

Flores Martínez’s initial curiosity sparked a long-term research partnership with scientist Gerardo Herrera Montalvo. Their ongoing study has revealed crucial insights into how these specialized mammals have evolved to exploit marine resources in Mexico’s Gulf of California islands, contributing valuable knowledge about adaptation and survival in extreme environments. The research continues to uncover new details about these extraordinary desert-dwelling, fish-eating bats.