The Bible tells us that God created all the great creatures of the sea, every living and moving thing with which the water teems, and every winged bird, on the fifth day of creation.1 The Bible, also, tells us that all wild animals, livestock and creatures that move along the ground, along with mankind, were created on the sixth day of creation.2
Quite often the question arises, "Could the six days of creation be longer than what we know as six days? Could this time period be thousands, or even millions of years?"
The biblical expression, "So the evening and the morning were the sixth day" would suggest that a day was a very short period of time. Remember, Adam and Eve (the first of mankind) lived past the sixth day; they saw the seventh day and even lived many years past that.3
1 (Genesis 1:21)
2 (Genesis 1:24-32)
3 (Genesis 2:2-3, 5:5)