We may be biased , but we mean the human brain is pretty special . All this workweek , mentalfloss.com is celebrate this miracle organ with aheap of brain[y ] stories , lists , and videos . It all take up toBrain Surgery Live With mental_floss , a two - time of day television event hosted by Bryant Gumbel .   The special strain Sunday , October 25 at 9 p.m. EST on the National Geographic Channel .

Brain size may not matter , but proportion for sure do . Thanks to a biology principle called Haller ’s Rule , the brain of small animal must take up more room to function . The result ? flyspeck animals have jumbo brains for their body sizing , while larger creature have hilariously small ones . emmet , for example , are 15 percent brain ! Humans ? Not even 3 pct . The fruity proportions entail some animals have unusual brains — just ask these guys .

1. TREE SHREW

The tree diagram termagant is a mystery . It ’s ratlike but closely related to prelate . scientist have fuss classifying the critter . Even more impressive ? It has the highest head - to - soundbox - flock proportion of any mammal , mystify humans .

2. SPERM WHALE

At or so 16 pounds , the spermatozoon whale ’s brain is the biggest on Edwin Herbert Land or in the sea . But do n’t be fooled . It ’s somewhat measly , considering the whale weighs 50 tons . Most of its head is filled with fatty , yellow tissue called junk .

3. GIANT SQUID

Circling around the esophagus , the giant   calamary ’s head is regulate like a donut — and weighs about as much as one , too . Since every meal passes through the calamary ’s mastermind , a large bite of food could in reality damage it .

4. CLARK’S NUTCRACKER

As with other corvids , the brain - to - trunk proportion of the Clark ’s Nutcracker rival that of dandy ape . The bird has a remarkable memory . Of the 30,000 pine tree junkie it buries a twelvemonth , it remembers where at least 70 percent of them are .

5. SPIDER

The lilliputian spider imagine on their feet — literally . Because their heads and trunk are so belittled , the primal uneasy system of small arachnid spills out of their heads … and into their leg .

Illustration by Daniel Downey. Alamy (Tree Shrew). iStock (Spider, Clark’s Nutcracker)