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 mammal is the Blue Whale which lives in the ocean and can grow to over 80 feet long. The largest land mammal is the elephant followed by the rhino and the hippo (which does spend a lot of time in the water). The smallest mammal is the Kitty's hog-nosed bat.