Blue Whales

• Blue whales are the largest mammals to ever live, and they may be the largest animal to ever live. They are found in all the oceans of the world. They are currently endangered, as whaling is believed to have killed off 99 percent of the population before the practice was made illegal in 1966. Prior to whaling, scientists estimated the blue whale population at 350,000. In 2008, the population is estimated at only 8,000 to 14,000. Research is currently being done on breeding habits, as the species' recovery has been relatively slow, and due to their enormous size, it would be extremely difficult to establish the kind of captive breeding programs utilized for other animals.
  
  

Breeding

• Blue whales reach sexual maturity when they are 6 to 10 years old. It is thought that some of their vocalizations, or "songs," are used to attract mates. Blue whales migrate to warm waters for mating, which takes place from late fall to very early spring. Even outside of mating season, blue whales are often seen together in male-female pairs, but it is not known if these are breeding pairs. Very little is known about what takes place in the breeding grounds, or if blue whales choose different partners every time.
  
  

Calves

• Females give birth every 2 to 3 years, almost always to a single calf. The gestation period is around 12 months, with births generally taking place at the very beginning of winter, in warmer, comparatively shallow waters. Calves are born tail first, and mothers make sure that they are near the surface, so the calf can take its first breath seconds after birth. The calf can swim after about 30 minutes; until then, the mother will help it to the surface with her flippers so it can breathe. Calves are 23 to 27 feet long and weigh 3 tons when they are born. They nurse for 7 to 8 months, drinking up to 100 gallons of milk per day. By the time they are weaned, they are about 52 feet long and weigh about 23 tons. The mother and calf stay together for at least a year, sometimes longer.