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.
(William West, AFP / Getty Images). The giant squid is the world's largest invertebrate, and the largest ever measured was 59 feet long. Giant squids also have the largest eyes of any animal, each one about the size of a human head. The etruscan shrew is the smallest mammal (by weight) in the world. The smallest animal by skull size is the bumblebee bat. The sea wasp jellyfish (pictured) has enough venom to kill 60 adult humans.