Assertion or assert may refer to: Assertion (software development), a computer programming technique. assert.h, a header file in the standard library of the C programming language. Assertion definition language, a specification language providing a formal grammar to specify behaviour and interfaces for computer software.
Grass snakes prey mainly on amphibians, especially the common toad and the common frog, although they may also occasionally eat ants and larvae. Captive snakes have been observed taking earthworms offered by hand, but dead prey items are never taken.
1 Snakes are predators and eat many animals thought to be pests, such as mice, voles, snails and slugs. Other prey items include insects, birds and their eggs, fish and frogs.  Snakes have hinged jaws that allow them to consume food that is wider than their bodies.