Toxin
The saliva of the northern short-tailed shrew contains a kallikrein-like protease, used to paralyze and subdue its prey. The toxin is strong enough to kill small animals, up to sizes somewhat larger than the shrew itself, and results in painful bites to humans who attempt to handle the shrew. The poisonous saliva is secreted from submaxillary glands, through a duct at the base of the lower incisors, where the saliva flows along the groove formed by the two incisors, and into the prey. The toxin is very similar in structure to the one used by the Mexican beaded lizard (Heloderma horridum), but evolved independently, however, from the same precursor protein.
One of the venom components, a peptide called soricidin, has been patented and is being investigated in Canada for pain control and as an anticancer drug. Another component is being studied in Japan as an antihypertensive agent.
Read more about this topic: Northern Short-tailed Shrew