Use selenium.webdriver.support.select.Select() and get the .options:
options
Returns a list of all options belonging to this select tag
from selenium.webdriver.support.select import Select
select = Select(driver.find_element_by_id('zoo'))
print [option.text for option in select.options]
where driver is a webdriver instance.
DEMO (using this w3schools page (yeah, sorry for w3schools :)):
>>> from selenium import webdriver
>>> from selenium.webdriver.support.select import Select
>>> driver = webdriver.Firefox()
>>> driver.get('http://www.w3schools.com/tags/tryit.asp?filename=tryhtml_select')
>>> driver.switch_to.frame('view')
>>> select = Select(driver.find_element_by_tag_name('select'))
>>> [option.text for option in select.options]
[u'Volvo', u'Saab', u'Opel', u'Audi']
Note that select element on this page doesn't have an id, so I just find it using find_element_by_tag_name(). Also note that there are iframes there, so I have to switch to the appropriate iframe to be able to find the element.
Hope that helps.