lower1. 1  to cause to descend; let or put down: to lower a flag. 2  to make lower in height or level: to lower the water in a canal. 3  to reduce in amount, price, degree, force, etc. 4  to make less loud: Please lower your voice.
Biggest Whale-Basilosaurus (60 Tons). Basilosaurus (Nobu Tamura). Unlike the other mammals on this list, Basilosaurus can't lay claim to being the largest-ever of its breed--that honor belongs to the still-extant Blue Whale, which can grow to as much as 200 tons.
The Largest Animal Ever: The Blue Whale. The blue whale (Balaenoptera musculus) is a marine mammal belonging to the suborder of baleen whales. At 30 metres (98 ft) in length and 180 metric tons (200 short tons) or more in weight, it is the largest known animal to have ever existed.