老鼠拖木锨，大头在后头

老鼠拖木鍁，大頭在後頭
lǎoshǔtuōmùxiān,dàtóuzàihòutou
  1. when the mice drag a shovel, the biggest thing comes second
  2. the tip of the iceberg
  3. the cockroach principle

CEDICT

Entry Composition

1 老鼠 lǎoshǔ
  1. (archaic dialectal, Guilin Mandarin) bat (animal)
  2. (countable) mouse and rat in general (Classifier: 隻／只 m c h)
  3. bat (animal)
  4. cunning, deceitful person
  5. mouse and rat in general (Classifier: 隻／只 m c h)

classifier: 隻
=2 拖 tuō variant of 拖 tuō
=2 拖 tuō
  1. to drag
  2. to tow
  3. to trail
  4. to hang down
  5. to mop (the floor)
  6. to delay
  7. to drag on
3 木 mù
  1. (bound form) tree
  2. (bound form) wood
  3. unresponsive; numb; wooden
4 锨 xiān shovel
5 大头 dàtóu
  1. big head
  2. mask in the shape of a big head
  3. the larger end of sth
  4. the main part
  5. the lion's share
  6. dupe
  7. sucker
  8. (old) silver coin with a bust of Yuan Shikai 袁世凯 Yuán Shìkǎi on the obverse side
6 在后 zàihòu behind
7 头 tou suffix for nouns