Termites or Dog?

[Ben Mills]

I'm currently looking at a rehab/flip in the Austin area and have been sent some pictures by the current owner.  Overall the place on the inside isn't bad at all.  There are a few doors to replace and it could use some paint but at face value it's all cosmetic.  But he sent me a picture that concerns me of the door leading to the back porch.  He claims his dog did the damage but I'm not so sure.  I'm going to attach it and would love to hear what you guys think.  I'm too new to rehabbing properties to just be able to look and know.  If it is termites what kind of costs would I be looking at potentially?  I realize there is a wide range but just having an idea would be a good starting point.

Thanks in advance for any and all responses!