Getting different number of aws snapshot than existing

When I try to do :

conn = boto.connect_ec2(access_key = "xxxxxxx", access_secret = "yyyyyy")
snapshots = conn.get_all_snapshots()

I get different number of snapshots(more than snapshots I see on console)

but when try to execute

snapshots = conn.get_all_snapshots(owner="xxxxxyyyyyyy")

I get real number of snapshot that I see on console.

Why is that behaviour in boto. Where I can find those extra snaphots.