Yes, we always have to be aware of risks, that includes things we might encounter on the road. If this is wildlife, then yes, the rider is taking sole responsibility. In many cities and townships there are very straight forward laws in regard to pets and the owners liability. Liability is a slippery slope that I'm sure we could debate in depth and we'd all have very different opinions come about.

Actually I just read a story about a group of riders were on a night ride, all wearing hi-vis and lights, but a driver ran into the group resulting in fatal injuries. The defense was the riders, all 100 of them, should not have been on the road at night and the driver wasn't responsible for the accident as it was the riders who were in the wrong place at the wrong time. Are the riders at fault because they opted to ride at night with reduced visibility and accepted that risk, even with lights and such, are they 'at fault' and free the driver responsibility?