Rat bite marks on chewcard.
Rats typically eat through the thickness of the card, leaving a jagged edge where chunks of the baited material have been removed. (By comparison, mice gnaw one side of the card and leave a smother edge.) Pairs of marks or holes, about 2 mm apart, may be left by the incisor teeth. They are very similar in form to those of possum but are much smaller in size.
Photograph: courtesy and © Manaaki Whenua – Landcare Research