What does it mean to be declared extinct?

Being declared extinct means a whole group of animals or plants has completely disappeared, like your favorite toy was lost forever and no one can find it anywhere.

Imagine you have a pet turtle named Tilly, and every day she lives in her tank at home. One day, you move to a new house, and you forget about Tilly. She stays behind, and over time, she gets lonely and sad. No one takes care of her anymore, and eventually, she passes away. If no other turtles like Tilly are found anywhere else in the world, then Tilly’s kind could be declared extinct.

Scientists look for clues, they check old pictures, search for any living members, and even dig up fossils. If they find no sign of life at all, after a long time, they say the group is officially extinct.

It’s like if you lost your favorite puzzle piece, and no one else in the world had that same piece, it would feel like it was never there to begin with!