Why shouldn't I use UNIVERSAL::isa?

Question

According to this

http://perldoc.perl.org/UNIVERSAL.html

I shouldn\'t use UNIVERSAL::isa() and should instead use $obj->isa() or CLASS->isa().

This means

Answer 1

Update for 2020: Perl v5.32 has the class infix operator, isa, which handles any sort of thing on the lefthand side. If the $something is not an object, you get back false with no blowup.

use v5.32;

if( $something isa 'Animal' ) { ... }