The declaration order is the problem - perl doesn't know about the locally declared classes in advance - try re-writing to read: 
#!/user/bin/perl -w
use strict;

############################
############################
package Animal;
{
 
  sub animalmethod
  {
    my ($self)=@_;
    print "I´m an animal. My name is $self->{Name}. I´m $self->{Age} y
+ears old\n";
  }

}

package Horse;
{

our @ISA=("Animal");

  sub new
  {
    my ($class, $name, $age) = @_;
    my $ref = {Name=>$name, Age=>$age};
    bless($ref, $class);
  }
 
  sub present
  {
    my ($self)=@_;

    if($self->isa("Animal"))
    {
        print "I'm an animal.\n";
    }

    else
    {
        print "I'm not an animal.\n";
    }
  }
}

package main;

my $horse1 = Horse->new("George the Horse", 12);
$horse1->present();
$horse1->animalmethod();

[download]
Doing so, then running the script gives 
$ perl tst.pl
I'm an animal.
I´m an animal. My name is George the Horse. I´m 12 years old

[download]
as expected.

A user level that continues to overstate my experience :-))

In reply to Re: Inheritance in Perl5 by Bloodnok
in thread Inheritance in Perl5 by tamaguchi

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.