It happened on Gladstone Lane and involved a dog that was off the lead.
The dog approached a member of the public and jumped up, biting the victim on the torso, before chasing the victim down the street.
The dog was a large Boxer-type dog and was with a man aged in his late-20s to early-30s.
A spokesperson for North Yorkshire Police said: “We are requesting the public’s assistance to help establish the full circumstances surrounding the incident.
“If this was you and your dog, I urge you to get in contact to work together to prevent any further incidents of a similar nature.”
Anyone with information about the incident which occurred at about 7.50pm on Saturday, May 5 is asked to contact the force on 101 and ask for PC 1092 Nick Simpson, quoting reference number 12180078344.