With December 18th almost around the corner in just 10 days I'm sure everyone is excited to see what kinds of rare pets or potentially URs they have adopted! However, it can be tricky to figure out which year your pets are from as the adoption date only shows December 18th, and not the original year.
Some veteran (or maybe even new!) users of CS might already be aware of my bot CS-Pound, a Discord bot that can automatically ping you a few minutes before pound/laf opens and can identify pets and items. You may have seen it in some CS-related Discord servers or even used it yourself to identify pets or be pinged. Most Discord users will probably be using that to identify their December 18th pets, so this solution is an alternative for those who don't use or don't like to use Discord.
Instead of asking around in forums or using Discord bots, I've created a simple website that allows you to paste in a direct link of a pet image and it will show you which year/event it came from along with a link to the CS archive of it. It's basically the identify function from my Discord bot extracted and put onto a website. It’s perfect for anyone who doesn’t use Discord or prefers a different option!
https://haruyuki.moe/dec18/
(The pink colour scheme is just a random colour scheme I thought looked nice)
(The pink colour scheme is just a random colour scheme I thought looked nice)

Example of identifiable pets:


Since the data for the new URs don't exist yet, if you enter in a link and it shows the pet doesn't exist in the database, you may have incorrectly entered the link or have a pet from this year (Some pets from 2024 are not added yet) or the new UR!

To get the direct link of a pet on Desktop right click the image of the pet and there should be something along the lines of "Copy Image Link".
For mobile users there are slight differences for whether you're on iOS or Android, but if you press down on the pet image there should be an option to "Copy" as well.
Best of luck with your December 18th pets this year!