Largest offspring

In the two months before it is born, the weight of a blue whale (Balaenoptera musculus) increases by as much as 2 tonnes (4,400 lb) - it grows about 1000 times faster than a human baby in the womb.  The newborn calf is 6-8 m (19-26 ft) long and weighs 2-3 tonnes (4,400-6,600 lb).  Everyday the baby drinks about 200 litres (351 pints) of its mother's milk and gains as much as 90 kg (198 lb) in weight (approximately the same as weight of an adult human being).  By the time it is weaned, at 7 months old, it has roughly doubled in length and weighs an amazing 20 tonnes (44,000 lb).