http://www.moscowzoo.ru/for-visitors/tickets/

the official site of the Zoopark...suppose the lines will be 3x around the block, so better either be there early or plan to be there the better part of the day. Monday is still - sanitation day-. grown ups 500 rubles 8.30 to 5 pm. 5 pm to 9 pm 600 rubles. kids till 17 go in for free. and of course the -usual- exemption for certain groups of people...