- SEPARATION ANXIETY What is Separation Anxiety Causes or Contributors of Separation Anxiety Fear of abandonment caused by prior re-homing. Second-hand dogs, dogs adopted from animal shelters, and rescued strays, are particlarly prone to develop separation anxiety problems. Changing one's daily routine, from where the dog spends most of its day with the owner, to where he spends most of his day ...inch.com/~dogs/separationanxiety.html