My 11 year old daughter is doing an extensive report on blue whales and have been unable to find the answer to the below questions. 1. What brings danger to blue whales? 2. What are their defenses? 3. Have there been any blue whales to be beached? 4. At what age do baby blue whales leave their mother? 5. Is there a difference in female and male blue whales? 1) Killer whales hunt blue whales. It is why they are called killer whales -- they are dolphins that kill whales, from the Basque "balaena assasina." A quarter of a century ago humans hunted blues. Ocean pollution also brings danger to blue whales. An ocean dirty with chemicals reduces the oceans' abilities to produce food for the great whales, and hence they would starve. Along the same line, a change in climate changes the ocean's properties. When an El Niņo event (warm water years) hit the Pacific coast of the Americas, upwelling (necessary for producing great amounts of krill, a primary blue whale food source) shuts down. Rarely, ships on the high seas are a danger for blue whales (collisions). 2) The greatest defenses for the blue are its speed and endurance. Although a killer whale can swim as fast as a blue (about 22 kts), they cannot do so for as long. Killer whales tire out after about 20 minutes. Blues can keep going at flank speed for much longer. The same ability helps in the food hunt. Blues are long-range travelers and can go hundreds of miles in days searching for food. 3) Occasionally, a blue whale is beached, but it is almost always after it had died at sea, and the carcass is brought to shore on the winds and tides. 4) Not a whole lot is known about the early life of blue whales, but calves do not stay with the mother more than a year -- especially if there is a new calf. Rarely, if the mom does not have a new calf the next year, a tenacious calf my hang around into its second year. Most baleen whales abandon their calves within about 7 to 10 months. 5) Other than the obvious differences in plumbing, male and female blues look essentially the same, except that females measure in about 2% larger than males of a similar age. I hope this helps. Pieter Folkens \\| \| Y _ ,~------------------------/ \___^___^._ | ~ ~.~ ~.~.~.~.~.~.~.~.~.'~`^--^_,''/ | @ _ ~,~.~'~.~,~'~.~,~.~ ~ ~ ~ ~.~ { \_________ \_l ~,~,~,~,~,~'.~.____'-----'__` \ ~ ~ `----------------------\__'--' ` `\ ~ ~