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.
And with lockdown prompting an upsurge in dog ownership, some charities have warned that there has been a corresponding increase in pet thefts.
5. Meg
A female border terrier cross, Meg went missing on April 17, 2019, on fields between Chorley Road and North in Much Hoole. She is brown and tan colouring with a small amount of white fur on her rear paw. Photo: Submit
6. Alfie
Alfie is a male Labrador retriever missing from his home in the Chipping area of Preston since October 2017. He is chocolate colours with a very small white patch on his chest. Other visible markings include a scar on his right side and a chipped tooth. Photo: Submit
7. Bobo
Bobo is a long-haired Akiti. Missing from his home on Hundred End Lane, Hesketh Bank, Preston, he has been micro chipped and has a lazy eye. He went missing from the back garden and was a collar with an ID tag at the time. Photo: Submit
8. Kylo
Kylo, a male cavalier King Charles spaniel, has been missing since October 17, 2020. He has Blenheim gold and white colouring and was last seen on the Pear Tree estate in Preston. A £2,000 reward is being offered for his safe return. Photo: Submit