can see twice as far as a human in moonlight, torchlight, and the dark itself 

an awakened ferret has the ability to detect approaching enemies, sniff out hidden foes, and track by sense of smell. In addition they can identify familiar odors just as humans do familiar sights

Get advantage rolls when hiding

can also fit through small spaces but has the same space and reach of similar creatures of the same size

+4 racial bonus on moving silently 

+8 racial bonus on balance and climb checks

use your dex mod for climb checks

speaks common and ferret

when you damage a creature with an attack or a spell and the creatures size is is larger then yours you may choose to have the attack deal extra damage. The extra damage is equal to 1d4

You can take the disengage or hide action as a bonus action