Having become a much-loved member of the family, the absence is acutely felt and extremely difficult to deal with.
So we can only imagine how Eoin Markey and his family felt when they received a phone call saying they would be were reunited with their beloved Staffordshire Bull Terrior, Mon, after a long three years spent apart.
Having escaped from the Markey's back garden in 2012, the four-year-old dog was spotted at Yorkgate train station by eagled- eyed workers in Belfast last week.
Thanks to a tiny microchip, Mon was reunited with her rightful owner, who said: "I couldn't believe it. I had to ask if they were sure it was Mon as she'd been missing for so long. It was a bolt out of the blue."
Having plastered his local area with posters in the aftermath of Mon's disappearance, Eoin started to lose hope and decided to replace the bull terrier.
However, he was overjoyed when he received a phone call from veterinary nurse, Gemma Vance, who informed Eoin his dog had finally been located, alive and well.
Commenting on the heartwarming discovery, Gemma said: "Mon was brought to us as a stray dog and so we scanned her for a microchip. Much to our relief she had been chipped by her owner and we were able to check the database and find not only her owner's contact details, but also that she had been missing since 2012."
Thankfully, the three year separation hadn't dimmed Mon's memory who bounded towards Eoin when he arrived to collect her, with her overjoyed owner saying: "I went in and called her and she came to me. The people thought that after so long she mightn't know me but they said she really seemed to know me."
Commenting on the impact Mon's return has had on his family, Eoin said: "We always wondered if she was still alive. Anyone who has lost a pet will know how heartbreaking it is."
We're delighted for the Markey family!
