But whatever the circumstances, a lost pet is like losing a member of the family.
For many owners, the search continues for years after the pet has come missing.
And with lockdown prompting an upsurge in dog ownership, some charities have warned that there has been a corresponding increase in pet thefts.
Here are a number of pets that remain listed as missing, from some listed in the past few weeks to some several years ago.
If you can help reunite any of these pets with their owners, visit the Lost Dogs website, and follow the links to the individual dog.
Fern went missing on February 2, 2021, after slipping her harness near Abbey Village football ground in Chorley and running towards a nearby farmers field. A female miniature Dachshund, she is described as a very nervous dog. A reward is being offered for his safe return.
Truffle is a female French bulldog stolen as a puppy from her home in Tulketh Crescent, Preston, in March 2019.
Rupert went missing in the Station Road area of Bamber Bridge on October 26, 2020. He was wearing a black harness when he went missing and is described as very timid and should not be chased or grabbed.
Female Cockerpoo, Ruby has bits of white fur on her chin and one paw. She went missing on Hudson Road, Preston, on May 21, 2022.