Very few functions in Perl does that. It will emit a warning instead.
As to why that is, perhaps someone with more Perl knowledge can chime in. I suspect it has to do with undef being inconvenient for signalling failure, since its evaluation will be context dependent (an array of undef is true but a numeric undef is false).
Type conversion is built into the language at a fundamental level. Languages that borrows the syntax but not the type model can be confusing in cases, but Perl is pretty consistent once you get the basics.
