Multiple rows into one row

Hello,

I can't find any reference in PostgreSQL documentation, if this is
possible:

I want to have some rows in one column, with the values separated for
example by a comma.

SELECT name FROM animals WHERE customer_id = '5'

- cat
- dog
- turtle

I would like to have this like this:

- cat, dog, turtle

So I could issue a SELECT like this:

SELECT customer.name, (SELECT name FROM animals WHERE customer_id =
customer.id) AS animals FROM customer

name animals
------- -----------
Peter dog,cat
Lisa turtle
Anthony bird,elephant

I could find info about PIVOT and some other extra functionalities
from other databases like Oracle, SQL server, ...

thanks,

raimon