Whales may migrate because of climate changes, water temperature, depth, salinity, topography of the sea floor, or abundance of food. How they know is a good question and it may be because the same group of whales go to the same places each year, so the older whales may remember and lead the younger whales. Think about going to school, your parents may take you the first time but later on as you know the way you can go by yourself and even start taking your younger brother or sister and teaching them.

A large variety of factors go into play to determine why big groups of whales move to certain places.It mostly has to do with where there is food available, what the quality of the water is like, whether the water is getting warmer and cooler (which changes with the seasons), and whether it's time to go to where they usually mate (which is also related to all the previous factors). Just as you might know where to go to get a good snack, the whales also know where they should head to get some food, but for them this might change depending on the time of year. For more information on whale migrations, check out this website: