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.
9. Lulu
Lulu is a female Yorkshire terrier cross. She went missing on January 19, 2020, on Knight Avenue, Buckshaw Village. She has no marks or scars but is considered very small for an adult dog. Photo: Submit
10. Nelly
A female French bulldog, Nelly went missing on March 31, 2021, from her home on Kestor Lane, Longridge. She has grey and tan colouring. Photo: Submit
11. Lola
Lola is a female Dachshund miniature with chocolate and tan colouring. Missing from her home on Oakenclough Road, Scorton, she was last seen near Salisbury Farm on Scorton around lunchtime on April 23, 2020. Photo: Submit
12. Blue
The female Staffordshire bull terror went missing on December 14, 2021, from her home in Ribbleton, Preston. Photo: Submit