The term “black snake” in North America typically refers to two common non-venomous species: the Eastern Rat Snake and the Eastern Racer. Found across diverse habitats, these opportunistic predators play a significant part in the ecological balance of their regions. Their varied diet shifts throughout their lives.
Primary Prey of Adult Black Snakes
The diet of a fully grown black snake is largely centered on warm-blooded animals, with a strong preference for rodents. Adult Eastern Rat Snakes are constrictors that primarily consume small mammals like mice, voles, and rats, subduing prey before swallowing it whole. Their exceptional climbing ability allows them to hunt in barns, attics, and trees, searching out nests of rodents and birds.
Birds and their eggs also make up a substantial portion of the rat snake’s food intake, especially during nesting season. While they may opportunistically consume amphibians or lizards, their large size makes calorie-rich mammalian and avian prey more efficient targets. In contrast, the Eastern Racer is a more active, visual hunter. Racers pursue smaller prey items, including small rodents, lizards, and other snakes, reflecting their different foraging strategy and smaller body mass.
How Diet Changes with Snake Size
The feeding habits of black snakes change significantly as they grow from hatchlings into large adults. Juvenile snakes possess a smaller gape size, meaning they cannot consume the large mice and rats that sustain their parents. Young black snakes, particularly those less than two feet long, focus on invertebrates like insects, small amphibians such as frogs and toads, and small lizards. As the snake increases in length and girth, the variety and size of prey expands. They gradually transition to the warm-blooded mammals and birds that define the adult diet.
The Benefit of Their Appetite to Humans
The predatory habits of black snakes translate directly into a substantial benefit for human communities, particularly in agricultural and residential settings. Their consistent consumption of rodents positions them as highly effective natural pest controllers. By preying on mice and rats, which contaminate food and cause structural damage, the snakes help mitigate significant economic losses. A single black snake can eliminate numerous rodent pests over a season, providing a form of biological control that reduces the need for chemical rodenticides. Furthermore, their appetite for small mammals helps to check the spread of diseases carried by these pests, such as hantavirus.