Silent Rattler

Target Species: Santa Catalina Rattlesnake, Crotalus catalinensis, and San Esteban Rattlesnake, Crotalus estebanensis
Location: Isla Los Lobos, Baja California Norte; Isla San Esteban, Sonora, and San Ignacio and Isla Santa Catalina, Baja California Sur, Mexico
Director: Roger Finnigan

Location: Baja California stretches approx. 1000 miles (1700km) south from Tijuana, an arid desert peninsula with numerous isolated offshore islands.

Mission Statement:

Rattlesnakes evolved rattles as audible warnings to protect themselves from short-sighted herds of heavy-footed mammals like buffalo, on the prairies of southwestern USA. However, some rattlesnakes are evolving away from owning a rattle, they don’t need to deter large animals because they live in habitats without such a threat. The rattleless rattlesnake of Santa Catalina Island in the Mexican Sea of Cortez has gone to whole way and lost its rattle completely. It neither requires a rattle for protection, nor, since it climbs bushes to catch birds, does it want a rattle. Mark and Baja California reptile expert Prof Lee Grismer set out to explore the gradual loss of the rattle in mainland and island rattlesnakes along the arid and forbidding Baja California peninsula. [Lee Grismer also introduces Mark to a curious group of lizards which feed on salt-rich marine isopods and have evolved a way of coping with otherwise fatally excessive levels of salt using large excretory glands on their snouts, but this section did not make the final film.]

A close view of the Santa Catalina Island rattlesnake (Crotalus catalinensis), note the complete absence of a rattle.

Species recorded during ‘Silent Rattler’